具有 2.5V 或 3.3V LVCMOS 输出的可编程 2-PLL VCXO 时钟合成器 - CDCE925

CDCE925 (正在供货)

具有 2.5V 或 3.3V LVCMOS 输出的可编程 2-PLL VCXO 时钟合成器

 

Special Note

Pre-programming of customer-specific settings is available. Contact your local Texas Instruments sales representative or local authorized distributor for more information.

描述

The CDCE925 and CDCEL925 are modular PLL-based low-cost, high-performance, programmable clock synthesizers, multipliers, and dividers. They generate up to five output clocks from a single input frequency. Each output can be programmed in-system for any clock frequency up to 230 MHz, using up to two independent configurable PLLs.

The CDCEx925 has a separate output supply pin, VDDOUT, which is 1.8 V for CDCEL925 and 2.5 V to 3.3 V for CDCE925.

The input accepts an external crystal or LVCMOS clock signal. In case of a crystal input, an on-chip load capacitor is adequate for most applications. The value of the load capacitor is programmable from 0 to 20 pF. Additionally, an on-chip VCXO is selectable which allows synchronization of the output frequency to an external control signal, that is, PWM signal.

The deep M/N divider ratio allows the generation of zero-ppm audio/video, networking (WLAN, Bluetooth, Ethernet, GPS), or interface (USB, IEEE1394, memory stick) clocks from a 27-MHz reference input frequency, for example.

All PLLs support SSC (spread-spectrum clocking). SSC can be center-spread or down-spread clocking, which is a common technique to reduce electromagnetic interference (EMI).

Based on the PLL frequency and the divider settings, the internal loop filter components are automatically adjusted to achieve high stability and optimized jitter transfer characteristic of each PLL.

The device supports nonvolatile EEPROM programming for easy customization of the device in the application. It is preset to a factory default configuration and can be reprogrammed to a different application configuration before it goes onto the PCB or reprogrammed by in-system programming. All device settings are programmable through the SDA/SCL bus, a 2-wire serial interface.

Three, free programmable control inputs, S0, S1, and S2, can be used to select different frequencies, or change the SSC setting for lowering EMI, or other control features like outputs disable to low, outputs in high-impedance state, power down, PLL bypass, and so forth.

The CDCx925 operates in a 1.8-V environment and in a temperature range of –40°C to 85°C.

特性

  • Member of Programmable Clock Generator Family
    • CDCEx913: 1-PLL, 3 Outputs
    • CDCEx925: 2-PLL, 5 Outputs
    • CDCEx925: 3-PLL, 7 Outputs
    • CDCEx949: 4-PLL, 9 Outputs
  • In-System Programmability and EEPROM
    • Serial Programmable Volatile Register
    • Nonvolatile EEPROM to Store Customer Settings
  • Flexible Input Clocking Concept
    • External Crystal: 8 MHz to 32 MHz
    • On-Chip VCXO: Pull Range ±150 ppm
    • Single-Ended LVCMOS Up to 160 MHz
  • Free Selectable Output Frequency Up to 230  MHz
  • Low-Noise PLL Core
    • PLL Loop Filter Components Integrated
    • Low Period Jitter (Typical 60 ps)
  • Separate Output Supply Pins
    • CDCE925: 3.3 V and 2.5 V
    • CDCEL925: 1.8 V
  • Flexible Clock Driver
    • Three User-Definable Control Inputs [S0/S1/S2], for Example, SSC Selection, Frequency Switching, Output Enable, or Power Down
    • Generates Highly Accurate Clocks for Video, Audio, USB, IEEE1394, RFID, Bluetooth®, WLAN, Ethernet™, and GPS
    • Generates Common Clock Frequencies Used With TI-DaVinci™, OMAP™, DSPs
    • Programmable SSC Modulation
    • Enables 0-PPM Clock Generation
  • 1.8-V Device Power Supply
  • Wide Temperature Range: –40°C to 85°C
  • Packaged in TSSOP
  • Development and Programming Kit for Easy PLL Design and Programming (TI Pro-Clock™)
  • APPLICATIONS
    • D-TVs, STBs, IP-STBs, DVD Players, DVD Recorders, and Printers

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参数 与其它产品相比 扩频时钟

 
Input Level
Output Level
Special Features
Rating
Pin/Package
Operating Temperature Range (C)
Approx. Price (US$)
Divider Ratio
Function
Jitter-Peak to Peak(P-P) or Cycle to Cycle(C-C)
No. of Outputs
Output Frequency (Max) (MHz)
Output Skew (ps)
Programmability
VCC (V)
CDCE925 CDCE913 CDCE937 CDCE949 CDCEL824 CDCEL913 CDCEL925 CDCEL937 CDCEL949
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
Crystal
LVCMOS   
LVCMOS    LVCMOS    LVCMOS    LVCMOS    LVCMOS    LVCMOS    LVCMOS    LVCMOS    LVCMOS   
Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
Integrated EEPROM
I2C
Pin Programming
Spread Spectrum Clocking (SSC)   
Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
  Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
Integrated EEPROM
Multiplier/Divider
Spread Spectrum Clocking (SSC)   
Catalog    Catalog    Catalog    Catalog    Catalog    Catalog    Catalog    Catalog    Catalog   
16TSSOP    14TSSOP    20TSSOP    24TSSOP    16TSSOP    14TSSOP    16TSSOP    20TSSOP    24TSSOP   
-40 to 85    -40 to 85    -40 to 85    -40 to 85    -40 to 85    -40 to 85    -40 to 85    -40 to 85    -40 to 85   
1.93 | 1ku    1.60 | 1ku    2.14 | 1ku    2.35 | 1ku    1.75 | 1ku    1.60 | 1ku    1.80 | 1ku    2.14 | 1ku    2.35 | 1ku   
Universal    Universal    Universal    Universal      Universal    Universal    Universal    Universal   
Clock Synthesizer    Clock Generator
Spread Spectrum Clock   
Clock Synthesizer    Clock Synthesizer    Clock Generator    Clock Synthesizer    Clock Synthesizer    Clock Synthesizer    Clock Synthesizer   
60 ps    60 ps    60 ps    60 ps    60 ps    60 ps    60 ps    60 ps    60 ps   
5    3    7    9    4    3    5    7    9   
230    230    230    230    201    230    230    230    230   
150    150    150    150    150    150    150    150    150   
EEPROM    EEPROM    EEPROM    EEPROM    EEPROM    EEPROM    EEPROM    EEPROM    EEPROM   
1.8    1.8    1.8    1.8    1.8    1.8    1.8    1.8    1.8   

特色工具和软件

WEBENCH® Designer CDCE925

Recommend Input Frequency Output Frequencies
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Input Frequency  MHz
 MHz  MHz