ZHCSDR9D July   2012  – May 2015 DS125BR401

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用范围
  3. 3 说明
  4. 4 典型应用
  5. 5 修订历史记录
  6. 6 说明（续）
  7. 7 Pin Configuration and Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Electrical Characteristics — Serial Management Bus Interface
    7. 8.7 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Typical 4-Level Input Thresholds
    4. 9.4 Device Functional Modes
      1. 9.4.1 Pin Control Mode
      2. 9.4.2 SMBUS Mode
    5. 9.5 Programming
      1. 9.5.1 PCIe Signal Integrity
        1. 9.5.1.1 RX-Detect in SAS/SATA (up to 6 Gbps) Applications
          1. 9.5.1.1.1 Signal Detect Control for Datarates Above 8 Gbps
        2. 9.5.1.2 MODE Operation With SMBus Registers
      2. 9.5.2 SMBUS Master Mode
      3. 9.5.3 System Management Bus (SMBus) and Configuration Registers
        1. 9.5.3.1 Transfer of Data Through the SMBus
        2. 9.5.3.2 SMBus Transactions
        3. 9.5.3.3 Writing a Register
        4. 9.5.3.4 Reading a Register
    6. 9.6 Register Maps
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 3.3-V or 2.5-V Supply Mode Operation
    2. 11.2 Power Supply Bypassing
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 PCB Layout Considerations for Differential Pairs
    2. 12.2 Layout Example
  13. 13器件和文档支持
    1. 13.1 文档支持
      1. 13.1.1 相关文档
    2. 13.2 Community Resources
    3. 13.3 商标
    4. 13.4 静电放电警告
    5. 13.5 术语表
  14. 14机械、封装和可订购信息

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

9 Detailed Description

9.1 Overview

The DS125BR401 device compensates for lossy printed-circuit-board (PCB) backplanes and balanced cables.

The DS125BR401 compensates for lossy FR-4 PCB backplanes and balanced cables. The DS125BR401 operates in 3 modes: Pin Control Mode (ENSMB = 0), SMBus Slave Mode (ENSMB = 1) and SMBus Master Mode (ENSMB = float) to load register informations from external EEPROM; refer to SMBUS Master Mode for additional information.

9.2 Functional Block Diagram

DS125BR401 30198786.gif
Figure 8. Block Diagram - Detail View Of Channel (1 Of 8)

9.3 Feature Description

The 4-level input pins use a resistor divider to help set the 4 valid levels and provide a wider range of control settings when ENSMB=0. There is an internal 30-kΩ pullup and a 60-kΩ pulldown connected to the package pin. These resistors, together with the external resistor connection combine to achieve the desired voltage level. Using the 1-kΩ pullup, 1-kΩ pulldown, no connect, and 20-kΩ pulldown provide the optimal voltage levels for each of the four input states.

Table 1. 4–Level Control Pin Settings

LEVEL SETTING 3.3-V MODE 2.5-V MODE
0 Tie 1 kΩ to GND 0.10 V 0.08 V
R Tie 20 kΩ to GND 1/3 × VIN 1/3 × VDD
Float Float (leave pin open) 2/3 × VIN 2/3 × VDD
1 Tie 1 kΩ to VIN or VDD VIN – 0.05 V VDD – 0.04 V

9.3.1 Typical 4-Level Input Thresholds

  • Level 1 - 2 = 0.2 × VIN or VDD
  • Level 2 - 3 = 0.5 × VIN or VDD
  • Level 3 - 4 = 0.8 × VIN or VDD

To minimize the start-up current associated with the integrated 2.5-V regulator, TI recommends using the 1-kΩ pullup and pulldown resistors. If several 4-level inputs require the same setting, it is possible to combine two or more 1-kΩ resistors into a single lower value resistor. As an example; combining two inputs with a single 500-Ω resistor is a good way to save board space.

9.4 Device Functional Modes

9.4.1 Pin Control Mode

When in pin mode (ENSMB = 0), equalization and de-emphasis can be selected through pin for each side independently. When de-emphasis is asserted VOD is automatically adjusted per Table 3. For PCIe applications, the RXDET pins provides automatic and manual control for input termination (50 Ω or >50 kΩ). MODE setting is also pin controllable with pin selections (PCIe Gen-1, PCIe Gen-2, auto detect, and PCIe Gen-3). The receiver electrical idle detect threshold is also adjustable through the SD_TH pin.

9.4.2 SMBUS Mode

When in SMBus mode (ENSMB = 1), the VOD (output amplitude), equalization, de-emphasis, and termination disable features are all programmable on a individual lane basis, instead of grouped by A or B as in the pin mode case. Upon assertion of ENSMB, the EQx and DEMx functions revert to register control immediately. The EQx and DEMx pins are converted to AD0-AD3 SMBus address inputs. The other external control pins (MODE, RXDET and SD_TH) remain active unless their respective registers are written to and the appropriate override bit is set, in which case they are ignored until ENSMB is driven low (pin mode). On power up and when ENSMB is driven low all registers are reset to their default state. If PWDN is asserted while ENSMB is high, the registers retain their current state.

Equalization settings accessible through the pin controls were chosen to meet the needs of most high speed applications. If additional fine tuning or adjustment is needed, additional equalization settings can be accessed through the SMBus registers. Each input has a total of 256 possible equalization settings. System Management Bus (SMBus) and Configuration Registers show the 16 setting when the device is in pin mode. When using SMBus mode, the equalization, VOD and de-emphasis levels are set by registers.

9.5 Programming

9.5.1 PCIe Signal Integrity

When using the DS125BR401 in PCIe Gen-3 systems, there are specific signal integrity settings to ensure signal integrity margin. The settings were optimized by extensive testing. Contact your field representative for more information regarding the testing completed to achieve these settings.

For tuning the in the downstream direction (from CPU to EP).

  • EQ: use the guidelines outlined in Table 2.
  • De-Emphasis: use the guidelines outlined in Table 3.
  • VOD: use the guidelines outlined in Table 3.

For tuning in the upstream direction (from EP to CPU).

  • EQ: use the guidelines outlined in Table 2.
  • De-Emphasis:
    • For trace lengths < 15 in set to –3.5 dB
    • For trace lengths > 15 in set to –6 dB
  • VOD: set to 900 mV

Table 2. Equalizer Settings

LEVEL EQA1
EQB1		 EQA0
EQB		 EQ – 8 bits [7:0] dB at
1.5 GHz		 dB at
2.5 GHz		 dB at
4 GHz		 dB at
6 GHz		 SUGGESTED USE(1)
1 0 0 0000 0000 = 0x00 2.5 3.5 3.8 3.1 FR4 < 5-inch trace
2 0 R 0000 0001 = 0x01 3.8 5.4 6.7 6.7 FR4 5- to 10-inch trace
3 0 Float 0000 0010 = 0x02 5 7 8.4 8.4 FR4 10-inch trace
4 0 1 0000 0011 = 0x03 5.9 8 9.3 9.1 FR4 15- to 20-inch trace
5 R 0 0000 0111 = 0x07 7.4 10.3 12.8 13.7 FR4 20- to 30-inch trace
6 R R 0001 0101 = 0x15 6.9 10.2 13.9 16.2 FR4 25- to 30-inch trace
7 R Float 0000 1011 = 0x0B 9 12.4 15.3 15.9 FR4 25- to 30-inch trace
8 R 1 0000 1111 = 0x0F 10.2 13.8 16.7 17 8-m, 30-AWG cable
9 Float 0 0101 0101 = 0x55 8.5 12.6 17.5 20.7 > 8-m cable
10 Float R 0001 1111 = 0x1F 11.7 16.2 20.3 21.8
11 Float Float 0010 1111 = 0x2F 13.2 18.3 22.8 23.6
12 Float 1 0011 1111 = 0x3F 14.4 19.8 24.2 24.7
13 1 0 1010 1010 = 0xAA 14.4 20.5 26.4 28
14 1 R 0111 1111 = 0x7F 16 22.2 27.8 29.2
15 1 Float 1011 1111 = 0xBF 17.6 24.4 30.2 30.9
16 1 1 1111 1111 = 0xFF 18.7 25.8 31.6 31.9
(1) Cable and FR4 lengths are for reference only. FR4 lengths based on a 100-Ω differential stripline with 5-mil traces and 8-mil trace separation. Optimal EQ setting should be determined through simulation and prototype verification.

Table 3. Output Voltage and De-Emphasis Settings

LEVEL DEMA1
DEMB1		 DEMA0
DEMB0		 VOD Vp-p DEM dB(1) INNER AMPLITUDE
Vp-p		 SUGGESTED USE(2)
1 0 0 0.8 0 0.8 FR4 <5-inch trace
2 0 R 0.9 0 0.9 FR4 <5-inch trace
3 0 Float 0.9 –3.5 0.6 FR4 10-inch trace
4 0 1 1 0 1 FR4 <5-inch trace
5 R 0 1 –3.5 0.7 FR4 10-inch trace
6 R R 1 –6 0.5 FR4 15-inch trace
7 R Float 1.1 0 1.1 FR4 <5-inch trace
8 R 1 1.1 –3.5 0.7 FR4 10-inch trace
9 Float 0 1.1 –6 0.6 FR4 15-inch trace
10 Float R 1.2 0 1.2 FR4 <5-inch trace
11 Float Float 1.2 –3.5 0.8 FR4 10-inch trace
12 Float 1 1.2 –6 0.6 FR4 15-inch trace
13 1 0 1.3 0 1.3 FR4 <5-inch trace
14 1 R 1.3 –3.5 0.9 FR4 10-inch trace
15 1 Float 1.3 –6 0.7 FR4 15-inch trace
16 1 1 1.3 –9 0.5 FR4 20-inch trace
(1) The VOD output amplitude and DEM de-emphasis levels are set with the DEMA/B[1:0] pins.
The de-emphasis levels are also available in PCIe Gen-3 mode when MODE = 1 (tied to VDD).
(2) FR4 lengths are for reference only. FR4 lengths based on a 100-Ω differential stripline with 5-mil traces and 8-mil trace separation. Optimal DEM settings should be determined through simulation and prototype verification.

Table 4. RX-Detect Settings

PWDN
(PIN 52)		 RXDET
(PIN 22)		 SMBus REG
bit[3:2]		 INPUT TERMINATION RECOMMENDED USE COMMENTS
0 0 00 Hi-Z X Manual RX-Detect, input is high impedance mode
0 Tie 20 kΩ
to GND		 01 Pre Detect: Hi-Z
Post Detect: 50 Ω		 PCIe only Auto RX-Detect, outputs test every 12 msec for 600 msec then stops; termination is Hi-Z until RX detection; once detected input termination is 50 Ω

Reset function by pulsing PWDN high for 5 usec then low again
0 Float
(Default)		 10 Pre Detect: Hi-Z
Post Detect: 50 Ω		 PCIe only Auto RX-Detect, outputs test every 12 msec until detection occurs; termination is Hi-Z until RX detection; once detected input termination is 50 Ω
0 1 11 50 Ω All Others Manual RX-Detect, input is 50 Ω
1 X High Impedance X Power-down mode, input is Hi-Z, output drivers are disabled

Used to reset RX-Detect State Machine when held high for 5 usec

9.5.1.1 RX-Detect in SAS/SATA (up to 6 Gbps) Applications

Unlike PCIe systems, SAS/SATA (up to 6 Gbps) systems use a low speed Out-Of-Band or OOB communications sequence to detect and communicate between Controllers/Expanders and target drives. This communication eliminates the need to detect for endpoints like PCIe. For SAS/SATA systems, TI recommends tying the RXDET pin high. This will ensure any OOB sequences sent from the Controller/Expander will reach the target drive without any additional latency due to the termination detection sequence defined by PCIe.

Table 5. Signal Detect Threshold Level(1)

SD_TH (PIN 26) SMBus REG bit [3:2] and [1:0] ASSERT LEVEL (TYP) DEASSERT LEVEL (TYP)
0 10 210 mVp-p 150 mVp-p
R 01 160 mVp-p 100 mVp-p
F (default) 00 180 mVp-p 110 mVp-p
1 11 190 mVp-p 130 mVp-p
(1) VDD = 2.5V, 25°C and 0101 pattern at 8 Gbps

9.5.1.1.1 Signal Detect Control for Datarates Above 8 Gbps

Signal detect bandwidth limitations combined with high levels of signal attenuation can result in intermittent data loss above 8 Gbps. This data loss can be eliminated by disabling automatic detection and forcing the Signal Detect function to be always "on". This programming requires SMBus control over the DS125BR401 to be present. The Signal Detect function is controlled for each channel independently. The register programming sequence is shown below:

  1. Write register 0x06 = 0x18 //* Enable SMBus register programming
  2. Write registers 0x0D[1]= 1'b, 0x14[1] = 1'b, 0x1B[1] = 1'b, 0x22[1] = 1'b //* CH0 - CH3
  3. Write registers 0x2A[1]= 1'b, 0x31[1] = 1'b, 0x38[1] = 1'b, 0x3F[1] = 1'b //* CH4 - CH7

Table 6. MODE Operation with Pin Control

MODE
(PIN 21)		 Driver Characteristics PCIe SAS
SATA		 10G-KR 10GbE CPRI
OBSAI		 SRIO
(R)XAUI		 Interlaken
Infiniband
0 Limiting X X X X X
R Nonlimiting without DE
F (default) Automatic X
1 Nonlimiting with DE X

Note: Automatic operation allows input to sense the incoming data rate and use a Nonlimiting output driver for operation at or above 8 Gbps.

Note: SAS/SATA up to 6 Gbps.

9.5.1.2 MODE Operation With SMBus Registers

When in SMBus mode (Slave or Master), the MODE pin retains control of the output driver characteristics. In order to override this control function, Register 0x08[2] must be written with a "1". Writing this bit enables MODE control of each channel individually using the channel registers defined in Table 7.

9.5.2 SMBUS Master Mode

The DS125BR401 device supports reading directly from an external EEPROM device by implementing SMBus Master mode. When using the SMBus master mode, the DS125BR401 will read directly from specific location in the external EEPROM. When designing a system for using the external EEPROM, the user must follow these specific guidelines. For additional information, refer to SNLA228.

  • Set ENSMB = Float — enable the SMBUS master mode.
  • The external EEPROM device address byte must be 0xA0 and capable of 1-MHz operation at 2.5-V and 3.3-V supply.
  • Set the AD[3:0] inputs for SMBus address byte. When the AD[3:0] = 0000'b, the device address byte is 0xB0.

When tying multiple DS125BR401 devices to the SDA and SCL bus, use these guidelines to configure the devices.

  • Use SMBus AD[3:0] address bits so that each device can loaded it's configuration from the EEPROM. Example below is for four devices.
    • U1: AD[3:0] = 0000 = 0xB0,
    • U2: AD[3:0] = 0001 = 0xB2,
    • U3: AD[3:0] = 0010 = 0xB4,
    • U4: AD[3:0] = 0011 = 0xB6
  • Use a pullup resistor on SDA and SCL; value = 2 kΩ
  • Daisy-chain READ_EN (pin 26) and ALL_DONE (pin 27) from one device to the next device in the sequence so that they do not compete for the EEPROM at the same time.
    1. Tie READ_EN of the first device in the chain (U1) to GND
    2. Tie ALL_DONE of U1 to READ_EN of U2
    3. Tie ALL_DONE of U2 to READ_EN of U3
    4. Tie ALL_DONE of U3 to READ_EN of U4
    5. Optional: Tie ALL_DONE output of U4 to a LED to show the devices have been loaded successfully

Below is an example of a 2 kbits (256 x 8-bit) EEPROM in hex format for the DS125BR401 device. The first 3 bytes of the EEPROM always contain a header common and necessary to control initialization of all devices connected to the I2C bus. CRC enable flag to enable/disable CRC checking. If CRC checking is disabled, a fixed pattern (8’hA5) is written/read instead of the CRC byte from the CRC location, to simplify the control. There is a MAP bit to flag the presence of an address map that specifies the configuration data start in the EEPROM. If the MAP bit is not present the configuration data start address is derived from the DS125BR401 address and the configuration data size. A bit to indicate an EEPROM size > 256 bytes is necessary to properly address the EEPROM. There are 37 bytes of data size for each DS125BR401 device. For additional information on EEPROM programming, refer to SNLA228.

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

NOTE

The maximum EEPROM size supported is 8-kbits (1024 × 8 bits).

Table 7. EEPROM Register Map - Single Device With Default Value

EEPROM Address Byte Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 BIt 0
Description 0x00 CRC EN Address Map Present EEPROM > 256 Bytes Reserved DEVICE COUNT[3] DEVICE COUNT[2] DEVICE COUNT[1] DEVICE COUNT[0]
Default Value 0x00 0 0 0 0 0 0 0 0
Description 0x01 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved
Default Value 0x00 0 0 0 0 0 0 0 0
Description 0x02 Max EEPROM Burst size[7] Max EEPROM Burst size[6] Max EEPROM Burst size[5] Max EEPROM Burst size[4] Max EEPROM Burst size[3] Max EEPROM Burst size[2] Max EEPROM Burst size[1] Max EEPROM Burst size[0]
Default Value 0x00 0 0 0 0 0 0 0 0
Description 0x03 PWDN_ch7 PWDN_ch6 PWDN_ch5 PWDN_ch4 PWDN_ch3 PWDN_ch2 PWDN_ch1 PWDN_ch0
SMBus Register 0x01 [7] 0x01 [6] 0x01 [5] 0x01 [4] 0x01 [3] 0x01 [2] 0x01 [1] 0x01 [0]
Default Value 0x00 0 0 0 0 0 0 0 0
Description 0x04 lpbk_1 lpbk_0 PWDN_INPUTS PWDN_OSC Ovrd_PWDN Reserved Reserved Reserved
SMBus Register 0x02 [5] 0x02 [4] 0x02 [3] 0x02 [2] 0x02 [0] 0x04 [7] 0x04 [6] 0x04 [5]
Default Value 00 0 0 0 0 0 0 0 0
Description 0x05 Reserved Reserved Reserved Reserved Reserved rxdet_btb_en Ovrd_idle_th Ovrd_RES
SMBus Register 0x04 [4] 0x04 [3] 0x04 [2] 0x04 [1] 0x04 [0] 0x06 [4] 0x08 [6] 0x08 [5]
Default Value 04 0 0 0 0 0 1 0 0
Description 0x06 Ovrd_IDLE Ovrd_RX_DET Ovrd_MODE Ovrd_RES Ovrd_RES rx_delay_sel_2 rx_delay_sel_1 rx_delay_sel_0
SMBus Register 0x08 [4] 0x08 [3] 0x08 [2] 0x08 [1] 0x08 [0] 0x0B [6] 0x0B [5] 0x0B [4]
Default Value 07 0 0 0 0 0 1 1 1
Description 0x07 RD_delay_sel_3 RD_delay_sel_2 RD_delay_sel_1 RD_delay_sel_0 ch0_Idle_auto ch0_Idle_sel ch0_RXDET_1 ch0_RXDET_0
SMBus Register 0x0B [3] 0x0B [2] 0x0B [1] 0x0B [0] 0x0E [5] 0x0E [4] 0x0E [3] 0x0E [2]
Default Value 00 0 0 0 0 0 0 0 0
Description 0x08 ch0_BST_7 ch0_BST_6 ch0_BST_5 ch0_BST_4 ch0_BST_3 ch0_BST_2 ch0_BST_1 ch0_BST_0
SMBus Register 0x0F [7] 0x0F [6] 0x0F [5] 0x0F [4] 0x0F [3] 0x0F [2] 0x0F [1] 0x0F [0]
Default Value 2F 0 0 1 0 1 1 1 1
Description 0x09 ch0_Sel_scp ch0_Sel_mode ch0_RES_2 ch0_RES_1 ch0_RES_0 ch0_VOD_2 ch0_VOD_1 ch0_VOD_0
SMBus Register 0x10 [7] 0x10 [6] 0x10 [5] 0x10 [4] 0x10 [3] 0x10 [2] 0x10 [1] 0x10 [0]
Default Value AD 1 0 1 0 1 1 0 1
Description 0x0A ch0_DEM_2 ch0_DEM_1 ch0_DEM_0 ch0_Slow ch0_idle_tha_1 ch0_idle_tha_0 ch0_idle_thd_1 ch0_idle_thd_0
SMBus Register 0x11 [2] 0x11 [1] 0x11 [0] 0x12 [7] 0x12 [3] 0x12 [2] 0x12 [1] 0x12 [0]
Default Value 40 0 1 0 0 0 0 0 0
Description 0x0B ch1_Idle_auto ch1_Idle_sel ch1_RXDET_1 ch1_RXDET_0 ch1_BST_7 ch1_BST_6 ch1_BST_5 ch1_BST_4
SMBus Register 0x15 [5] 0x15 [4] 0x15 [3] 0x15 [2] 0x16 [7] 0x16 [6] 0x16 [5] 0x16 [4]
Default Value 02 0 0 0 0 0 0 1 0
Description 0x0C ch1_BST_3 ch1_BST_2 ch1_BST_1 ch1_BST_0 ch1_Sel_scp ch1_Sel_mode ch1_RES_2 ch1_RES_1
SMBus Register 0x16 [3] 0x16 [2] 0x16 [1] 0x16 [0] 0x17 [7] 0x17 [6] 0x17 [5] 0x17 [4]
Default Value FA 1 1 1 1 1 0 1 0
Description 0x0D ch1_RES_0 ch1_VOD_2 ch1_VOD_1 ch1_VOD_0 ch1_DEM_2 ch1_DEM_1 ch1_DEM_0 ch1_Slow
SMBus Register 0x17 [3] 0x17 [2] 0x17 [1] 0x17 [0] 0x18 [2] 0x18 [1] 0x18 [0] 0x19 [7]
Default Value 2F 1 1 0 1 0 1 0 0
Description 0x0E ch1_idle_tha_1 ch1_idle_tha_0 ch1_idle_thd_1 ch1_idle_thd_0 ch2_Idle_auto ch2_Idle_sel ch2_RXDET_1 ch2_RXDET_0
SMBus Register 0x19 [3] 0x19 [2] 0x19 [1] 0x19 [0] 0x1C [5] 0x1C [4] 0x1C [3] 0x1C [2]
Default Value 00 0 0 0 0 0 0 0 0
Description 0x0F ch2_BST_7 ch2_BST_6 ch2_BST_5 ch2_BST_4 ch2_BST_3 ch2_BST_2 ch2_BST_1 ch2_BST_0
SMBus Register 0x1D [7] 0x1D [6] 0x1D [5] 0x1D [4] 0x1D [3] 0x1D [2] 0x1D [1] 0x1D [0]
Default Value 2F 0 0 1 0 1 1 1 1
Description 0x10 ch2_Sel_scp ch2_Sel_mode ch2_RES_2 ch2_RES_1 ch2_RES_0 ch2_VOD_2 ch2_VOD_1 ch2_VOD_0
SMBus Register 0x1E [7] 0x1E [6] 0x1E [5] 0x1E [4] 0x1E [3] 0x1E [2] 0x1E [1] 0x1E [0]
Default Value AD 1 0 1 0 1 1 0 1
Description 0x11 ch2_DEM_2 ch2_DEM_1 ch2_DEM_0 ch2_Slow ch2_idle_tha_1 ch2_idle_tha_0 ch2_idle_thd_1 ch2_idle_thd_0
SMBus Register 0x1F [2] 0x1F [1] 0x1F [0] 0x20 [7] 0x20 [3] 0x20 [2] 0x20 [1] 0x20 [0]
Default Value 40 0 1 0 0 0 0 0 0
Description 0x12 ch3_Idle_auto ch3_Idle_sel ch3_RXDET_1 ch3_RXDET_0 ch3_BST_7 ch3_BST_6 ch3_BST_5 ch3_BST_4
SMBus Register 0x23 [5] 0x23 [4] 0x23 [3] 0x23 [2] 0x24 [7] 0x24 [6] 0x24 [5] 0x24 [4]
Default Value 02 0 0 0 0 0 0 1 0
Description 0x13 ch3_BST_3 ch3_BST_2 ch3_BST_1 ch3_BST_0 ch3_Sel_scp ch3_Sel_mode ch3_RES_2 ch3_RES_1
SMBus Register 0x24 [3] 0x24 [2] 0x24 [1] 0x24 [0] 0x25 [7] 0x25 [6] 0x25 [5] 0x25 [4]
Default Value FA 1 1 1 1 1 0 1 0
Description 0x14 ch3_RES_0 ch3_VOD_2 ch3_VOD_1 ch3_VOD_0 ch3_DEM_2 ch3_DEM_1 ch3_DEM_0 ch3_Slow
SMBus Register 0x25 [3] 0x25 [2] 0x25 [1] 0x25 [0] 0x26 [2] 0x26 [1] 0x26 [0] 0x27 [7]
Default Value D4 1 1 0 1 0 1 0 0
Description 0x15 ch3_idle_tha_1 ch3_idle_tha_0 ch3_idle_thd_1 ch3_idle_thd_0 ovrd_fast_idle en_high_idle_th_n en_high_idle_th_s en_fast_idle_n
SMBus Register 0x27 [3] 0x27 [2] 0x27 [1] 0x27 [0] 0x28 [6] 0x28 [5] 0x28 [4] 0x28 [3]
Default Value 09 0 0 0 0 0 0 0 1
Description 0x16 en_fast_idle_s eqsd_mgain_n eqsd_mgain_s ch4_Idle_auto ch4_Idle_sel ch4_RXDET_1 ch4_RXDET_0 ch4_BST_7
SMBus Register 0x28 [2] 0x28 [1] 0x28 [0] 0x2B [5] 0x2B [4] 0x2B [3] 0x2B [2] 0x2C [7]
Default Value 80 1 0 0 0 0 0 0 0
Description 0x17 ch4_BST_6 ch4_BST_5 ch4_BST_4 ch4_BST_3 ch4_BST_2 ch4_BST_1 ch4_BST_0 ch4_Sel_scp
SMBus Register 0x2C [6] 0x2C [5] 0x2C [4] 0x2C [3] 0x2C [2] 0x2C [1] 0x2C [0] 0x2D [7]
Default Value 5F 0 1 0 1 1 1 1 1
Description 0x18 ch4_Sel_mode ch4_RES_2 ch4_RES_1 ch4_RES_0 ch4_VOD_2 ch4_VOD_1 ch4_VOD_0 ch4_DEM_2
SMBus Register 0x2D [6] 0x2D [5] 0x2D [4] 0x2D [3] 0x2D [2] 0x2D [1] 0x2D [0] 0x2E [2]
Default Value 5A 0 1 0 1 1 0 1 0
Description 0x19 ch4_DEM_1 ch4_DEM_0 ch4_Slow ch4_idle_tha_1 ch4_idle_tha_0 ch4_idle_thd_1 ch4_idle_thd_0 ch5_Idle_auto
SMBus Register 0x2E [1] 0x2E [0] 0x2F [7] 0x2F [3] 0x2F [2] 0x2F [1] 0x2F [0] 0x32 [5]
Default Value 80 1 0 0 0 0 0 0 0
Description 0x1A ch5_Idle_sel ch5_RXDET_1 ch5_RXDET_0 ch5_BST_7 ch5_BST_6 ch5_BST_5 ch5_BST_4 ch5_BST_3
SMBus Register 0x32 [4] 0x32 [3] 0x32 [2] 0x33 [7] 0x33 [6] 0x33 [5] 0x33 [4] 0x33 [3]
Default Value 05 0 0 0 0 0 1 0 1
Description 0x1B ch5_BST_2 ch5_BST_1 ch5_BST_0 ch5_Sel_scp ch5_Sel_mode ch5_RES_2 ch5_RES_1 ch5_RES_0
SMBus Register 0x33 [2] 0x33 [1] 0x33 [0] 0x34 [7] 0x34 [6] 0x34 [5] 0x34 [4] 0x34 [3]
Default Value F5 1 1 1 1 0 1 0 1
Description 0x1C ch5_VOD_2 ch5_VOD_1 ch5_VOD_0 ch5_DEM_2 ch5_DEM_1 ch5_DEM_0 ch5_Slow ch5_idle_tha_1
SMBus Register 0x34 [2] 0x34 [1] 0x34 [0] 0x35 [2] 0x35 [1] 0x35 [0] 0x36 [7] 0x36 [3]
Default Value A8 1 0 1 0 1 0 0 0
Description 0x1D ch5_idle_tha_0 ch5_idle_thd_1 ch5_idle_thd_0 ch6_Idle_auto ch6_Idle_sel ch6_RXDET_1 ch6_RXDET_0 ch6_BST_7
SMBus Register 0x36 [2] 0x36 [1] 0x36 [0] 0x39 [5] 0x39 [4] 0x39 [3] 0x39 [2] 0x3A [7]
Default Value 00 0 0 0 0 0 0 0 0
Description 0x1E ch6_BST_6 ch6_BST_5 ch6_BST_4 ch6_BST_3 ch6_BST_2 ch6_BST_1 ch6_BST_0 ch6_Sel_scp
SMBus Register 0x3A [6] 0x3A [5] 0x3A [4] 0x3A [3] 0x3A [2] 0x3A [1] 0x3A [0] 0x3B [7]
Default Value 5F 0 1 0 1 1 1 1 1
Description 0x1F ch6_Sel_mode ch6_RES_2 ch6_RES_1 ch6_RES_0 ch6_VOD_2 ch6_VOD_1 ch6_VOD_0 ch6_DEM_2
SMBus Register 0x3B [6] 0x3B [5] 0x3B [4] 0x3B [3] 0x3B [2] 0x3B [1] 0x3B [0] 0x3C [2]
Default Value 5A 0 1 0 1 1 0 1 0
Description 0x20 ch6_DEM_1 ch6_DEM_0 ch6_Slow ch6_idle_tha_1 ch6_idle_tha_0 ch6_idle_thd_1 ch6_idle_thd_0 ch7_Idle_auto
SMBus Register 0x3C [1] 0x3C [0] 0x3D [7] 0x3D [3] 0x3D [2] 0x3D [1] 0x3D [0] 0x40 [5]
Default Value 80 1 0 0 0 0 0 0 0
Description 0x21 ch7_Idle_sel ch7_RXDET_1 ch7_RXDET_0 ch7_BST_7 ch7_BST_6 ch7_BST_5 ch7_BST_4 ch7_BST_3
SMBus Register 0x40 [4] 0x40 [3] 0x40 [2] 0x41 [7] 0x41 [6] 0x41 [5] 0x41 [4] 0x41 [3]
Default Value 05 0 0 0 0 0 1 0 1
Description 0x22 ch7_BST_2 ch7_BST_1 ch7_BST_0 ch7_Sel_scp ch7_Sel_mode ch7_RES_2 ch7_RES_1 ch7_RES_0
SMBus Register 0x41 [2] 0x41 [1] 0x41 [0] 0x42 [7] 0x42 [6] 0x42 [5] 0x42 [4] 0x42 [3]
Default Value F5 1 1 1 1 0 1 0 1
Description 0x23 ch7_VOD_2 ch7_VOD_1 ch7_VOD_0 ch7_DEM_2 ch7_DEM_1 ch7_DEM_0 ch7_Slow ch7_idle_tha_1
SMBus Register 0x42 [2] 0x42 [1] 0x42 [0] 0x43 [2] 0x43 [1] 0x43 [0] 0x44 [7] 0x44 [3]
Default Value A8 1 0 1 0 1 0 0 0
Description 0x24 ch7_idle_tha_0 ch7_idle_thd_1 ch7_idle_thd_0 Reserved Reserved Reserved Reserved Reserved
SMBus Register 0x44 [2] 0x44 [1] 0x44 [0] 0x47 [3] 0x47 [2] 0x47 [2] 0x47 [0] 0x48 [7]
Default Value 00 0 0 0 0 0 0 0 0
Description 0x25 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved
SMBus Register 0x48 [6] 0x4C [7] 0x4C [6] 0x4C [5] 0x4C [4] 0x4C [3] 0x4C [0] 0x59 [0]
Default Value 00 0 0 0 0 0 0 0 0
Description 0x26 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved
SMBus Register 0x5A [7] 0x5A [6] 0x5A [5] 0x5A [4] 0x5A [3] 0x5A [2] 0x5A [1] 0x5A [0]
Default Value 54 0 1 0 1 0 1 0 0
Description 0x27 Reserved Reserved Reserved Reserved Reserved Reserved Reserved Reserved
SMBus Register 0x5B [7] 0x5B [6] 0x5B [5] 0x5B [4] 0x5B [3] 0x5B [2] 0x5B [1] 0x5B [0]
Default Value 54 0 1 0 1 0 1 0 0

Table 8. Example of EEPROM for Four Devices Using Two Address Maps

EEPROM Address Address (Hex) EEPROM Data Comments
0 00 0x43 CRC_EN = 0, Address Map = 1, >256 bytes = 0, Device Count[3:0] = 3
1 01 0x00
2 02 0x08 EEPROM Burst Size
3 03 0x00 CRC not used
4 04 0x0B Device 0 Address Location
5 05 0x00 CRC not used
6 06 0x0B Device 1 Address Location
7 07 0x00 CRC not used
8 08 0x30 Device 2 Address Location
9 09 0x00 CRC not used
10 0A 0x30 Device 3 Address Location
11 0B 0x00 Begin Device 0, 1 - Address Offset 3
12 0C 0x00
13 0D 0x04
14 0E 0x07
15 0F 0x00
16 10 0x00 EQ CHB0 = 00
17 11 0xAB VOD CHB0 = 1 V
18 12 0x00 DEM CHB0 = 0 (0 dB)
19 13 0x00 EQ CHB1 = 00
20 14 0x0A VOD CHB1 = 1 V
21 15 0xB0 DEM CHB1 = 0 (0 dB)
22 16 0x00
23 17 0x00 EQ CHB2 = 00
24 18 0xAB VOD CHB2 = 1 V
25 19 0x00 DEM CHB2 = 0 (0 dB)
26 1A 0x00 EQ CHB3 = 00
27 1B 0x0A VOD CHB3 = 1 V
28 1C 0xB0 DEM CHB3 = 0 (0 dB)
29 1D 0x01
30 1E 0x80
31 1F 0x01 EQ CHA0 = 00
32 20 0x56 VOD CHA0 = 1 V
33 21 0x00 DEM CHA0 = 0 (0 dB)
34 22 0x00 EQ CHA1 = 00
35 23 0x15 VOD CHA1 = 1 V
36 24 0x60 DEM CHA1 = 0 (0 dB)
37 25 0x00
38 26 0x01 EQ CHA2 = 00
39 27 0x56 VOD CHA2 = 1 V
40 28 0x00 DEM CHA2 = 0 (0 dB)
41 29 0x00 EQ CHA3 = 00
42 2A 0x15 VOD CHA3 = 1 V
43 2B 0x60 DEM CHA3 = 0 (0 dB)
44 2C 0x00
45 2D 0x00
46 2E 0x54
47 2F 0x54 End Device 0, 1 - Address Offset 39
48 30 0x00 Begin Device 2, 3 - Address Offset 3
49 31 0x00
50 32 0x04
51 33 0x07
52 34 0x00
53 35 0x00 EQ CHB0 = 00
54 36 0xAB VOD CHB0 = 1 V
55 37 0x00 DEM CHB0 = 0 (0 dB)
56 38 0x00 EQ CHB1 = 00
57 39 0x0A VOD CHB1 = 1 V
58 3A 0xB0 DEM CHB1 = 0 (0 dB)
59 3B 0x00
60 3C 0x00 EQ CHB2 = 00
61 3D 0xAB VOD CHB2 = 1 V
62 3E 0x00 DEM CHB2 = 0 (0 dB)
63 3F 0x00 EQ CHB3 = 00
64 40 0x0A VOD CHB3 = 1 V
65 41 0xB0 DEM CHB3 = 0 (0 dB)
66 42 0x01
67 43 0x80
68 44 0x01 EQ CHA0 = 00
69 45 0x56 VOD CHA0 = 1 V
70 46 0x00 DEM CHA0 = 0 (0 dB)
71 47 0x00 EQ CHA1 = 00
72 48 0x15 VOD CHA1 = 1 V
73 49 0x60 DEM CHA1 = 0 (0 dB)
74 4A 0x00
75 4B 0x01 EQ CHA2 = 00
76 4C 0x56 VOD CHA2 = 1 V
77 4D 0x00 DEM CHA2 = 0 (0 dB)
78 4E 0x00 EQ CHA3 = 00
79 4F 0x15 VOD CHA3 = 1 V
80 50 0x60 DEM CHA3 = 0 (0 dB)
81 51 0x00
82 52 0x00
83 53 0x54
84 54 0x54 End Device 2, 3 - Address Offset 39

Note: CRC_EN = 0, Address Map = 1, >256 byte = 0, Device Count[3:0] = 3. This example has all eight channels set to EQ = 00 (min boost), VOD = 1 V, DEM = 0 (0 dB) and multiple device can point to the same address map. Maximum EEPROM size is 8Kb (1024 × 8 bits).

9.5.3 System Management Bus (SMBus) and Configuration Registers

The System Management Bus interface is compatible to SMBus 2.0 physical layer specification. ENSMB = 1 kΩ to VDD to enable SMBus slave mode and allow access to the configuration registers.

The DS125BR401 has the AD[3:0] inputs in SMBus mode. These pins are the user set SMBUS slave address inputs. The AD[3:0] pins have internal pulldown. When left floating or pulled low the AD[3:0] = 0000'b, the device default address byte is 0xB0. Based on the SMBus 2.0 specification, the DS125BR401 has a 7-bit slave address. The LSB is set to 0'b (for a WRITE). The device supports up to 16 address byte, which can be set with the AD[3:0] inputs. Table 9 shows the 16 addresses.

Table 9. Device Slave Address Bytes

AD[3:0] Settings Address Bytes (HEX)
0000 B0
0001 B2
0010 B4
0011 B6
0100 B8
0101 BA
0110 BC
0111 BE
1000 C0
1001 C2
1010 C4
1011 C6
1100 C8
1101 CA
1110 CC
1111 CE

The SDA, SCL pins are 3.3-V tolerant, but are not 5-V tolerant. External pullup resistor is required on the SDA. The resistor value can be from 1 kΩ to 5 kΩ depending on the voltage, loading and speed. The SCL may also require an external pullup resistor and it depends on the Host that drives the bus.

9.5.3.1 Transfer of Data Through the SMBus

During normal operation the data on SDA must be stable during the time when SCL is High.

There are three unique states for the SMBus:

START: A High-to-Low transition on SDA while SCL is High indicates a message START condition.

STOP: A Low-to-High transition on SDA while SCL is High indicates a message STOP condition.

IDLE: If SCL and SDA are both High for a time exceeding tBUF from the last detected STOP condition or if they are High for a total exceeding the maximum specification for tHIGH then the bus will transfer to the IDLE state.

9.5.3.2 SMBus Transactions

The device supports WRITE and READ transactions. See Table 10 for register address, type (Read/Write, Read Only), default value and function information.

9.5.3.3 Writing a Register

To write a register, the following protocol is used (see SMBus 2.0 specification).

  1. The Host drives a START condition, the 7-bit SMBus address, and a “0” indicating a WRITE.
  2. The Device (Slave) drives the ACK bit (“0”).
  3. The Host drives the 8-bit Register Address.
  4. The Device drives an ACK bit (“0”).
  5. The Host drive the 8-bit data byte.
  6. The Device drives an ACK bit (“0”).
  7. The Host drives a STOP condition.

The WRITE transaction is completed, the bus goes IDLE and communication with other SMBus devices may now occur.

9.5.3.4 Reading a Register

To read a register, the following protocol is used (see SMBus 2.0 specification).

  1. The Host drives a START condition, the 7-bit SMBus address, and a 0 indicating a WRITE.
  2. The Device (Slave) drives the ACK bit (0).
  3. The Host drives the 8-bit Register Address.
  4. The Device drives an ACK bit (0).
  5. The Host drives a START condition.
  6. The Host drives the 7-bit SMBus Address, and a 1 indicating a READ.
  7. The Device drives an ACK bit 0.
  8. The Device drives the 8-bit data value (register contents).
  9. The Host drives a NACK bit 1 indicating end of the READ transfer.
  10. The Host drives a STOP condition.

The READ transaction is completed, the bus goes IDLE and communication with other SMBus devices may now occur.

See Table 10 for more information.

9.6 Register Maps

Table 10. SMBUS Slave Mode Register Map

Address Register Name Bit Field Type Default EEPROM Bit Description
0x00 Device Address Observation 7 Reserved R/W 0x00 Set bit to 0.
6:3 Address Bit
AD[3:0]		 R Observation of AD[3:0] bits
[6]: AD3
[5]: AD2
[4]: AD1
[3]: AD0
2 EEPROM Read Done R 1: Device completed the read from external EEPROM.
1:0 Reserved R/W Set bits to 0.
0x01 PWDN Channels 7:0 PWDN CHx R/W 0x00 Yes Power Down per Channel
[7]: CH7 – CHA_3
[6]: CH6 – CHA_2
[5]: CH5 – CHA_1
[4]: CH4 – CHA_0
[3]: CH3 – CHB_3
[2]: CH2 – CHB_2
[1]: CH1 – CHB_1
[0]: CH0 – CHB_0
0x00 = all channels enabled
0xFF = all channels disabled
Note: override PWDN pin.
0x02 Override PWDN,
LPBK Control		 7:6 Reserved R/W 0x00 Set bits to 0.
5:4 LPBK
Control		 Yes 00: Use LPBK pin control
01: INA_n to OUTB_n loopback
10: INB_n to OUTA_n loopback
11: Disable loopback and ignore LPBK pin.
3:1 Reserved Set bits to 0.
0 Override PWDN
pin		 Yes 1: Block PWDN pin control
0: Allow PWDN pin control
0x03 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x04 Reserved 7:0 Reserved R/W 0x00 Yes Set bits to 0
0x05 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x05 Reserved 7:0 Reserved R/W 0x00 Reserved
0x06 Slave Register Control 7:5 Reserved R/W 0x10 Set bits to 0.
4 Reserved Yes Set bit to 1.
3 Register Enable 1 = Enable SMBus Register Control
0 = Disable SMBus Register Control
Note: In order to change VOD, DEM, and EQ of the channels in slave mode, this bit must be set to 1.
0x07 Digital Reset and Control 7 Reserved R/W 0x01 Set bit to 0.
6 Reset Registers Self clearing bit, set to 1 to reset the register to default values
5 Reset SMBus Master Self clearing reset to SMBus master state machine
4:0 Reserved Set bits to 0 0001'b.
0x08 Override
Pin Control 		7 Reserved R/W 0x00 Set bit to 0.
6 Override SD_TH Yes 1: Block SD_TH pin control
0: Allow SD_TH pin control
5 Reserved Yes Set bit to 0.
4 Override IDLE Yes 1: IDLE control by registers
0: IDLE control by signal detect
3 Override RXDET Yes 1: Block RXDET pin control
0: Allow RXDET pin control
2 Override MODE Yes 1: Block MODE pin control
0: Allow MODE pin control
1 Reserved Set bit to 0.
0 Reserved Set bit to 0.
0x09 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x0A Signal Detect Monitor 7:0 SD_TH Status R 0x00 CH7 - CH0 Internal Signal Detector Indicator
[7]: CH7 - CHA_3
[6]: CH6 - CHA_2
[5]: CH5 - CHA_1
[4]: CH4 - CHA_0
[3]: CH3 - CHB_3
[2]: CH2 - CHB_2
[1]: CH1 - CHB_1
[0]: CH0 - CHB_0
0 = Signal detected at input (active data)
1 = Signal not detected at input (idle state)
NOTE: These bits only function when RATE pin = FLOAT
0x0B Reserved 7 Reserved R/W 0x00 Set bits to 0
6:0 Reserved R/W 0x70 Yes Set bits to 111 0000'b
0x0C Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x0D CH0 - CHB0
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x0E CH0 - CHB0
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x0F CH0 - CHB0
EQ		 7:0 EQ Control R/W 0x2F Yes IB0 EQ Control - total of 256 levels.
See Table 2.
0x10 CH0 - CHB0
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OB0 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x11 CH0 - CHB0
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH0 - CHB0.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH0 - CHB0.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OB0 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x12 CH0 - CHB0
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x13 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x14 CH1 - CHB1
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x15 CH1 - CHB1
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is high-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x16 CH1 - CHB1
EQ		 7:0 EQ Control R/W 0x2F Yes IB1 EQ Control - total of 256 levels.
See Table 2.
0x17 CH1 - CHB1
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OB1 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x18 CH1 - CHB1
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH1 - CHB1.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH1 - CHB1.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OB1 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x19 CH1 - CHB1
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x1A Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x1B CH2 - CHB2
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x1C CH2 - CHB2
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x1D CH2 - CHB2
EQ		 7:0 EQ Control R/W 0x2F Yes IB2 EQ Control - total of 256 levels.
See Table 2.
0x1E CH2 - CHB2
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OB2 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x1F CH2 - CHB2
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH2 - CHB2.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH2 - CHB2.
00: PCIe Gen-1 (2.5 G)
01: PCIe Gen-2 (5 G)
11: PCIe Gen-3 (8 G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OB2 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x20 CH2 - CHB2
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x21 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x22 CH3 - CHB3
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x23 CH3 - CHB3
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x24 CH3 - CHB3
EQ		 7:0 EQ Control R/W 0x2F Yes IB3 EQ Control - total of 256 levels.
See Table 2.
0x25 CH3 - CHB3
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OB0 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x26 CH3 - CHB3
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH3 - CHB3.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH3 - CHB3.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OB3 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x27 CH3 - CHB3
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x28 Signal Detect Control 7:6 Reserved R/W 0x0C Set bits to 0.
5:4 High IDLE Yes Enable higher range of Signal Detect Thresholds
[5]: CH0 - CH3
[4]: CH4 -CH7
3:2 Fast IDLE Yes Enable Fast OOB response
[3]: CH0 - CH3
[2]: CH4 -CH7
1:0 Reduced SD Gain Yes Enable reduced Signal Detect Gain
[1]: CH0 - CH3
[0]: CH4 -CH7
0x29 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x2A CH4 - CHA0
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x2B CH4 - CHA0
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x2C CH4 - CHA0
EQ		 7:0 EQ Control R/W 0x2F Yes IA0 EQ Control - total of 256 levels.
See Table 2.
0x2D CH4 - CHA0
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OA0 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x2E CH4 - CHA0
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH4 - CHA0.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH4 - CHA0.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OA0 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x2F CH4 - CHA0
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x30 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x31 CH5 - CHA1
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x32 CH5 - CHA1
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x33 CH5 - CHA1
EQ		 7:0 EQ Control R/W 0x2F Yes IA1 EQ Control - total of 256 levels.
See Table 2.
0x34 CH5 - CHA1
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OA1 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x35 CH5 - CHA1
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH5 - CHA1.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH5 - CHA1.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OA1 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x36 CH5 - CHA1
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x37 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x38 CH6 - CHA2
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x39 CH6 - CHA2
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x3A CH6 - CHA2
EQ		 7:0 EQ Control R/W 0x2F Yes IA2 EQ Control - total of 256 levels.
See Table 2.
0x3B CH6 - CHA2
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OA2 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x3C CH6 - CHA2
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH6 - CHA2.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH6 - CHA2.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OA2 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x3D CH6 - CHA2
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x3E Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x3F CH7 - CHA3
Signal Detect		 7:3 Reserved R/W 0x00 Set bits to 0.
2 SD Reset 1: Force signal detect "off"
0: Normal operation
1 SD Preset 1: Force signal detect "on"
0: Normal operation
0 Reserved Set bit to 0.
0x40 CH7 - CHA3
IDLE, RXDET		 7:6 Reserved R/W 0x00 Set bits to 0.
5 IDLE_AUTO Yes 1 = Allow IDLE_SEL control in bit 4
0 = Automatic IDLE detect
Note: override IDLE control.
4 IDLE_SEL Yes 1: Output is MUTED (electrical idle)
0: Output is ON
Note: override IDLE control.
3:2 RXDET Yes 00: Input is hi-z impedance
01: Auto RX-Detect,
outputs test every 12 ms for 600 ms (50 times) then stops; termination is hi-z until detection; once detected input termination is 50 Ω
10: Auto RX-Detect,
outputs test every 12 ms until detection occurs; termination is hi-z until detection; once detected input termination is 50 Ω
11: Input is 50 Ω
Note: override RXDET pin.
1:0 Reserved Set bits to 0.
0x41 CH7 - CHA3
EQ		 7:0 EQ Control R/W 0x2F Yes IA3 EQ Control - total of 256 levels.
See Table 2.
0x42 CH7 - CHA3
VOD 		7 Short Circuit Protection R/W 0xAD Yes 1: Enable the short circuit protection
0: Disable the short circuit protection
6 MODE_SEL Yes 1: PCIe Gen-1 or PCIe Gen-2
0: PCIe Gen-3
Note: override the MODE pin.
5:3 Reserved Yes Set bits to default value - 101.
2:0 VOD Control Yes OA3 VOD Control
000: 0.7 V
001: 0.8 V
010: 0.9 V
011: 1 V
100: 1.1 V
101: 1.2 V (default)
110: 1.3 V
111: 1.4 V
0x43 CH7 - CHA3
DEM		 7 RXDET STATUS R 0x02 Observation bit for RXDET CH7 - CHA3.
1: RX = detected
0: RX = not detected
6:5 MODE_DET STATUS R Observation bit for MODE_DET CH7 - CHA3.
00: PCIe Gen-1 (2.5G)
01: PCIe Gen-2 (5G)
11: PCIe Gen-3 (8G+)
Note: Only functions when MODE Pin = Automatic
4:3 Reserved R/W Set bits to 0.
2:0 DEM Control R/W Yes OA3 DEM Control
000: 0 dB
001: –1.5 dB
010: –3.5 dB (default)
011: –5 dB
100: –6 dB
101: –8 dB
110: –9 dB
111: –12 dB
0x44 CH7 - CHA3
IDLE Threshold		 7:4 Reserved R/W 0x00 Set bits to 0.
3:2 IDLE tha Yes Assert threshold
00 = 180 mVp-p (default)
01 = 160 mVp-p
10 = 210 mVp-p
11 = 190 mVp-p
Note: override the SD_TH pin.
1:0 IDLE thd Yes Deassert threshold
00 = 110 mVp-p (default)
01 = 100 mVp-p
10 = 150 mVp-p
11 = 130 mVp-p
Note: override the SD_TH pin.
0x45 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x46 Reserved 7:0 Reserved R/W 0x38 Set bits to 0x38
0x47 Reserved 7:4 Reserved R/W 0x00 Set bits to 0
3:0 Reserved R/W Yes Set bits to 0
0x48 Reserved 7:6 Reserved R/W 0x05 Yes Set bits to 0
5:0 Reserved R/W Set bits to 00 0101'b
0x49 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x4A Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x4B Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x4C Reserved 7:3 Reserved R/W 0x00 Yes Set bits to 0
2:1 Reserved R/W Set bits to 0
0 Reserved R/W Yes Set bits to 0
0x4D Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x4E Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x4F Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x50 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x51 Device ID 7:5 VERSION R 0x44 010'b
4:0 ID 00100'b
0x52 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x53 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x54 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x55 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x56 Reserved 7:0 Reserved R/W 0x10 Set bits to 0x10
0x57 Reserved 7:0 Reserved R/W 0x64 Set bits to 0x64
0x58 Reserved 7:0 Reserved R/W 0x21 Set bits to 0x21
0x59 Reserved 7:1 Reserved R/W 0x00 Set bits to 0
0 Reserved Yes Set bit to 0
0x5A Reserved 7:0 Reserved R/W 0x54 Yes Set bits to 0x54
0x5B Reserved 7:0 Reserved R/W 0x54 Yes Set bits to 0x54
0x5C Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x5D Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x5E Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x5F Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x60 Reserved 7:0 Reserved R/W 0x00 Set bits to 0
0x61 Reserved 7:0 Reserved R/W 0x00 Set bits to 0