ZHCS321I June   2009  – January 2015 ISO1050


  1. 特性
  2. 应用
  3. 说明
  4. 修订历史记录
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics: Supply Current
    6. 6.6  Electrical Characteristics: Driver
    7. 6.7  Electrical Characteristics: Receiver
    8. 6.8  Switching Characteristics: Device
    9. 6.9  Switching Characteristics: Driver
    10. 6.10 Switching Characteristics: Receiver
    11. 6.11 Typical Characteristics
  7. Parameter Measurement Information
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 CAN Bus States
      2. 8.3.2 Digital Inputs and Outputs
      3. 8.3.3 Protection Features
        1. TXD Dominant Time-Out (DTO)
        2. Thermal Shutdown
        3. Undervoltage Lockout and Fail-Safe
        4. Floating Pins
        5. CAN Bus Short-Circuit Current Limiting
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. Bus Loading, Length and Number of Nodes
        2. CAN Termination
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 PCB Material
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 文档支持
      1. 12.1.1 相关文档
    2. 12.2 商标
    3. 12.3 静电放电警告
    4. 12.4 术语表
  13. 13机械封装和可订购信息


请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • DUB|8
  • DW|16
散热焊盘机械数据 (封装 | 引脚)

8 Detailed Description

8.1 Overview

The ISO1050 is a digitally isolated CAN transceiver with a typical transient immunity of 50 kV/µs. The device can operate from 3.3-V supply on side 1 and 5-V supply on side 2. This is of particular advantage for applications operating in harsh industrial environments because the 3.3 V on side 1 enables the connection to low-volt microcontrollers for power preservation, whereas the 5 V on side 2 maintains a high signal-to-noise ratio of the bus signals.

8.2 Functional Block Diagram

ISO1050 fbd_slls983.gif

8.3 Feature Description

Table 2. Isolator Characteristics(1)(2)

L(I01) Minimum air gap (Clearance) Shortest pin-to-pin distance through air, per JEDEC package dimensions DUB-8 6.1 mm
L(I02) Minimum external tracking (Creepage) Shortest pin-to-pin distance across the package surface, per JEDEC package dimensions 6.8 mm
L(I01) Minimum air gap (Clearance) Shortest pin-to-pin distance through air, per JEDEC package dimensions DW-16 8.34 mm
L(I02) Minimum external tracking (Creepage) Shortest pin-to-pin distance across the package surface, per JEDEC package dimensions 8.10 mm
Minimum Internal Gap (Internal Clearance) Distance through the insulation 0.014 mm
RIO Isolation resistance Input to output, VIO = 500 V, all pins on each side of the barrier tied together creating a two-pin device,
TA = 25°C
>1012 Ω
Input to output, VIO = 500 V, 100°C ≤TA ≤TA max >1011 Ω
CIO Barrier capacitance VI = 0.4 sin (4E6πt) 1.9 pF
CI Input capacitance to ground VI = 0.4 sin (4E6πt) 1.3 pF
(1) Creepage and clearance requirements should be applied according to the specific equipment isolation standards of an application. Care should be taken to maintain the creepage and clearance distance of a board design to ensure that the mounting pads of the isolator on the printed-circuit-board do not reduce this distance.
(2) Creepage and clearance on a printed-circuit-board become equal according to the measurement techniques shown in the Isolation Glossary. Techniques such as inserting grooves and/or ribs on a printed-circuit-board are used to help increase these specifications.

Table 3. Insulation Characteristics

VIORM Maximum working insulation voltage per DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 ISO1050DUB 560 Vpeak
ISO1050DW 1200
VPR Input to output test voltage per DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 ISO1050DUB VPR = 1.875 x VIORM, t = 1 sec (100% production)
Partial discharge < 5 pC
1050 Vpeak
ISO1050DW 2250
VIOTM Transient overvoltage per DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 t = 60 sec (qualification) 4000 Vpeak
t = 1 sec (100% production)
VISO Isolation voltage per UL 1577 ISO1050DUB - Double Protection t = 60 sec (qualification)
2500 Vrms
t = 1 sec (100% production) 3000
ISO1050DW - Single Protection t = 60 sec (qualification) 4243 Vrms
t = 1 sec (100% production) 5092
RS Isolation resistance VIO = 500 V at TS > 109 Ω
Pollution Degree 2

Table 4. IEC 60664-1 Ratings

Basic isolation group Material group II
Installation classification Rated mains voltage ≤ 150 Vrms I–IV
Rated mains voltage ≤ 300 Vrms I–III
Rated mains voltage ≤ 400 Vrms I–II
Rated mains voltage ≤ 600 Vrms (ISO1050DW only) I-II
Rated mains voltage ≤ 848 Vrms (ISO1050DW only) I

Table 5. IEC Safety Limiting Values(1)

IS Safety input, output, or supply current DUB-8 θJA = 73.3 °C/W, VI = 5.5 V, TJ = 150°C, TA = 25°C 310 mA
θJA = 73.3 °C/W, VI = 3.6 V, TJ = 150°C, TA = 25°C 474
DW-16 θJA = 76 °C/W, VI = 5.5 V, TJ = 150°C, TA = 25°C 299 mA
θJA = 76 °C/W, VI = 3.6 V, TJ = 150°C, TA = 25°C 457
TS Maximum case temperature 150 °C
(1) Safety limiting intends to prevent potential damage to the isolation barrier upon failure of input or output circuitry. A failure of the I/O can allow low resistance to ground or the supply and, without current limiting dissipate sufficient power to overheat the die and damage the isolation barrier potentially leading to secondary system failures.

The safety-limiting constraint is the absolute maximum junction temperature specified in the absolute maximum ratings table. The power dissipation and junction-to-air thermal impedance of the device installed in the application hardware determines the junction temperature. The assured junction-to-air thermal resistance in Thermal Information is that of a device installed on a High-K Test Board for Leaded Surface Mount Packages. The power is the recommended maximum input voltage times the current. The junction temperature is then the ambient temperature plus the power times the junction-to-air thermal resistance.

ISO1050 thermal1_slls983.gifFigure 21. DUB-8 θJC Thermal Derating Curve per VDE
ISO1050 thermal2_slls983.gifFigure 22. DW-16 θJC Thermal Derating Curve per VDE

Table 6. Regulatory Information

Certified according to DIN V VDE V 0884-10 (VDE V 0884-10):2006-12 & DIN EN 61010-1 Certified according to EN/UL/CSA 60950-1 Approved under CSA Component Acceptance Notice 5A Recognized under 1577 Component Recognition Program(1) Certified according to GB4943.1-2011
Basic Insulation
Transient Overvoltage, 4000 VPK
Surge Voltage, 4000 VPK
Maximum Working Voltage, 1200 VPK (ISO1050DW) and
560 VPK (ISO1050DUB)
5000 VRMS Reinforced Insulation,
400 VRMS maximum working voltage
5000 VRMS Basic Insulation,
600 VRMS maximum working voltage
2500 VRMS Reinforced Insulation,
400 VRMS maximum working voltage
2500 VRMS Basic Insulation,
600 VRMS maximum working voltage
5000 VRMS Reinforced Insulation
2 Means of Patient Protection at 125 VRMS per IEC 60601-1 (3rd Ed.)
ISO1050DUB: 2500 VRMS Double Protection
ISO1050DW: 3500 VRMS Double Protection,
4243 VRMS Single Protection
Reinforced Insulation, Altitude ≤ 5000 m, Tropical Climate, 250 VRMS maximum working voltage
Certificate number: 40016131 Certificate number: U8V 11 09 77311 008 Master contract number: 220991 File number: E181974 Certificate number: CQC14001109541
(1) Production tested ≥ 3000 VRMS (ISO1050DUB) and 5092 VRMS (ISO1050DW) for 1 second in accordance with UL 1577.

8.3.1 CAN Bus States

The CAN bus has two states during operation: dominant and recessive. A dominant bus state, equivalent to logic low, is when the bus is driven differentially by a driver. A recessive bus state is when the bus is biased to a common mode of VCC / 2 through the high-resistance internal input resistors of the receiver, equivalent to a logic high. The host microprocessor of the CAN node will use the TXD pin to drive the bus and will receive data from the bus on the RXD pin. See Figure 23 and Figure 24.

ISO1050 bus_states_llsea2.gifFigure 23. Bus States (Physical Bit Representation)
ISO1050 Simplified_Recessive_Common_Mode_Bias_and_Receiver_SLLSED7.gifFigure 24. Simplified Recessive Common Mode Bias and Receiver

8.3.2 Digital Inputs and Outputs

TXD (Input) and RXD (Output):
VCC1 for the isolated digital input and output side of the device maybe supplied by a 3.3-V or 5-V supply and thus the digital inputs and outputs are 3.3-V and 5-V compatible.


TXD is very weakly internally pulled up to VCC1. An external pullup resistor should be used to make sure that TXD is biased to recessive (high) level to avoid issues on the bus if the microprocessor doesn't control the pin and TXD floats. TXD pullup strength and CAN bit timing require special consideration when the device is used with an open-drain TXD output on the CAN controller of the microprocessor. An adequate external pullup resistor must be used to ensure that the TXD output of the microprocessor maintains adequate bit timing input to the input on the transceiver.

8.3.3 Protection Features TXD Dominant Time-Out (DTO)

TXD DTO circuit prevents the local node from blocking network communication in the event of a hardware or software failure where TXD is held dominant longer than the time-out period tTXD_DTO. The TXD DTO circuit timer starts on a falling edge on TXD. The TXD DTO circuit disables the CAN bus driver if no rising edge is seen before the time-out period expires. This frees the bus for communication between other nodes on the network. The CAN driver is re-activated when a recessive signal is seen on the TXD pin, thus clearing the TXD DTO condition. The receiver and RXD pin still reflect the CAN bus, and the bus pins are biased to recessive level during a TXD dominant time-out.


The minimum dominant TXD time allowed by the TXD DTO circuit limits the minimum possible transmitted data rate of the device. The CAN protocol allows a maximum of eleven successive dominant bits (on TXD) for the worst case, where five successive dominant bits are followed immediately by an error frame. This, along with the tTXD_DTO minimum, limits the minimum data rate. Calculate the minimum transmitted data rate by: Minimum Data Rate = 11 / tTXD_DTO.

ISO1050 example_timing_lls983.gifFigure 25. Example Timing Diagram for Devices With TXD DTO Thermal Shutdown

If the junction temperature of the device exceeds the thermal shut down threshold the device turns off the CAN driver circuits thus blocking the TXD to bus transmission path. The shutdown condition is cleared when the junction temperature drops below the thermal shutdown temperature of the device. If the fault condition is still present, the temperature may rise again and the device would enter thermal shut down again. Prolonged operation with thermal shutdown conditions may affect device reliability.


During thermal shutdown the CAN bus drivers turn off; thus no transmission is possible from TXD to the bus. The CAN bus pins are biased to recessive level during a thermal shutdown, and the receiver to RXD path remains operational. Undervoltage Lockout and Fail-Safe

The supply pins have undervoltage detection that places the device in protected or fail-safe mode. This protects the bus during an undervoltage event on VCC1 or VCC2 supply pins. If the bus-side power supply Vcc2 is lower than about 2.7V, the power shutdown circuits in the ISO1050 will disable the transceiver to prevent false transmissions due to an unstable supply. If Vcc1 is still active when this occurs, the receiver output (RXD) will go to a fail-safe HIGH (recessive) value in about 6 microseconds.

Table 7. Undervoltage Lockout and Fail-Safe

GOOD GOOD Functional Per Device State and TXD Mirrors Bus
BAD GOOD Protected Recessive High Impedance (3-state)
GOOD BAD Protected High Impedance Recessive (Fail-Safe High)


After an undervoltage condition is cleared and the supplies have returned to valid levels, the device typically resumes normal operation in 300 µs Floating Pins

Pullups and pulldowns should be used on critical pins to place the device into known states if the pins float. The TXD pin should be pulled up through a resistor to VCC1 to force a recessive input level if the microprocessor output to the pin floats. CAN Bus Short-Circuit Current Limiting

The device has several protection features that limit the short-circuit current when a CAN bus line is shorted. These include driver current limiting (dominant and recessive). The device has TXD dominant state time out to prevent permanent higher short-circuit current of the dominant state during a system fault. During CAN communication the bus switches between dominant and recessive states with the data and control fields bits, thus the short-circuit current may be viewed either as the instantaneous current during each bus state, or as a DC average current. For system current (power supply) and power considerations in the termination resistors and common-mode choke ratings, use the average short-circuit current. Determine the ratio of dominant and recessive bits by the data in the CAN frame plus the following factors of the protocol and PHY that force either recessive or dominant at certain times:

  • Control fields with set bits
  • Bit-stuffing
  • Interframe space
  • TXD dominant time-out (fault case limiting)

These ensure a minimum recessive amount of time on the bus even if the data field contains a high percentage of dominant bits.


The short-circuit current of the bus depends on the ratio of recessive to dominant bits and their respective short-circuit currents. The average short-circuit current may be calculated with the following formula:

IOS(AVG) = %Transmit × [(%REC_Bits × IOS(SS)_REC) + (%DOM_Bits × IOS(SS)_DOM)] + [%Receive × IOS(SS)_REC]


  • IOS(AVG) is the average short-circuit current.
  • %Transmit is the percentage the node is transmitting CAN messages.
  • %Receive is the percentage the node is receiving CAN messages.
  • %REC_Bits is the percentage of recessive bits in the transmitted CAN messages.
  • %DOM_Bits is the percentage of dominant bits in the transmitted CAN messages.
  • IOS(SS)_REC is the recessive steady state short-circuit current.
  • IOS(SS)_DOM is the dominant steady state short-circuit current.


Consider the short.circuit current and possible fault cases of the network when sizing the power ratings of the termination resistance and other network components.

8.4 Device Functional Modes

Table 8. Driver Function Table

TXD(1) CANH(1) CANL(1)
L H L Dominant
H Z Z Recessive
(1) H = high level, L = low level, Z = common mode (recessive) bias to VCC / 2. See Figure 23 and Figure 24 for bus state and common mode bias information.

Table 9. Receiver Function Table

Normal or Silent VID ≥ 0.9 V Dominant L
0.5 V < VID < 0.9 V ? ?
VID ≤ 0.5 V Recessive H
Open (VID ≈ 0 V) Open H
(1) H = high level, L = low level, ? = indeterminate.

Table 10. Function Table(1)

H Z Z RECESSIVE 0.5 V < VID < 0.9 V ? ?
(1) H = high level; L = low level; X = irrelevant; ? = indeterminate; Z = high impedance
(2) Logic low pulses to prevent dominant time-out.
ISO1050 io_sch_lls983.gifFigure 26. Equivalent I/O Schematics