CDCE925

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Programmable 2-PLL VCXO Clock Synthesizer with 2.5-V or 3.3-V LVCMOS Outputs

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Product details

Parameters

Function Clock synthesizer Number of outputs 5 Output frequency (Max) (MHz) 230 Core supply voltage (V) 1.8 Output supply voltage (V) 3.3, 2.5 Input type XTAL, LVCMOS Output type LVCMOS Operating temperature range (C) -40 to 85 Features Integrated EEPROM, Multiplier or divider, Spread-spectrum clocking (SSC) Rating Catalog open-in-new Find other Clock generators

Package | Pins | Size

TSSOP (PW) 16 22 mm² 4.4 x 5 open-in-new Find other Clock generators

Features

  • 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

All other trademarks are the property of their respective owners

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Description

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.

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Technical documentation

= Top documentation for this product selected by TI
No results found. Please clear your search and try again. View all 13
Type Title Date
* Datasheet CDCE(L)925: Flexible Low Power LVCMOS Clock Generator With SSC Support for EMI Reduction datasheet (Rev. I) Oct. 27, 2016
Technical articles How to select an optimal clocking solution for your FPGA-based design Dec. 09, 2015
Technical articles Clocking sampled systems to minimize jitter Jul. 31, 2014
Technical articles Timing is Everything: How to optimize clock distribution in PCIe applications Mar. 28, 2014
Application notes VCXO Application Guideline for CDCE(L)9xx Family (Rev. A) Apr. 23, 2012
User guides CDCE(L)9XX & CDCEx06 Programming Evaluation Module Manual (Rev. A) Nov. 22, 2010
User guides CDCE(L)9xx Performance Evaluation Module (Rev. A) Jul. 07, 2010
Application notes General I2C / EEPROM usage for the CDCE(L)9xx family Jan. 26, 2010
Application notes Troubleshooting I2C Bus Protocol Oct. 19, 2009
Application notes Usage of I2C for CDCE(L)949, CDCE(L)937, CDCE(L)925, CDCE(L)913 Sep. 23, 2009
User guides CDCE(L)9XX & CDCEx06 Programming Evaluation Module Manual Dec. 09, 2008
Application notes Generating Low Phase-Noise Clocks for Audio Data Converters from Low Frequency Mar. 31, 2008
Application notes Practical consideration on choosing a crystal for CDCE(L)9xx family Mar. 24, 2008

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

EVALUATION BOARDS Download
149
Description

The CDCE925Perf-Evaluation Module allows the verification of the functionality and performance of CDCE925 and CDCEL925 with the options of crystal and 1.8 V LVCMOS inputs. The outputs can be connected to the Oscilloscope directly with SMA cables.

Features

  1. Easy-to-use evaluation module for fast prototyping and application evaluation
  2. Easy and fast device programming through TI Pro-Clock software
  3. Evaluation of multiple crystals and reference clocks due to flexible input structure
  4. EVM completely USB powered in factory default
  5. Option for USB power and (...)

EVALUATION BOARDS Download
99
Description

The clock generator CDCE(L)949 family has integrated EEPROM that allows the default frequency settings to be saved upon start up. CDCEL9XXPROGEVM is a programming board that allows a fast programming of prototyping samples or small production quantities. It applies to all 8 devices in the family (...)

EVALUATION BOARDS Download
document-generic User guide
199
Description

The DP83822EVM supports 100BASE-FX, 100BASE-TX and 10BASE-Te. This design has been tested and validated at UNH for compliance. It is also emissions Class A certified and is rated to ±8-kV IEC61000-4-2 (contact discharge).

The DP83822EVM incudes two onboard status LEDs and a 5-V USB connector with (...)

Features
  • 100BASE-TX, 100BASE-FX and 10BASE-Te compliant
  • MII, RMII master, RMII slave and RGMII MAC interfaces
  • Low-power modes: Energy-efficient Ethernet, wake-on-LAN, active sleep, passive sleep, IEEE power down, deep power down
  • IEEE 1588 start-of-frame detection
  • Supports error-free data transfer over 150 m (...)
GUIS FOR EVALUATION MODULES (EVM) Download
SCAC073F.ZIP (88940 KB)

Software development

DRIVERS & LIBRARIES Download
Linux Driver for CDCE925
CDCE925SW-LINUX The Linux driver supports the CDCE925 Programmable 2-PLL VCXO Clock Synthesizer with 2.5-V or 3.3-V LVCMOS Outputs. The Linux driver supports communication through the I2C bus.
Linux Mainline Status

Available in Linux Main line: Yes
Available through git.ti.com: N/A

Supported Devices:
  • cdce925
Linux Source (...)
DRIVERS & LIBRARIES Download
SCAC131.ZIP (77 KB)
PROGRAMMING TOOLS Download
ClockPro™ Programming Software
CLOCKPRO TI's ClockPro software allows users to program/configure the following devices in a friendly GUI interface:
  • CDCE949
  • CDCE937
  • CDCE925
  • CDCE913
  • CDCE906
  • CDCE706
  • CDCEL949
  • CDCEL937
  • CDCEL925
  • CDCEL913

It is intended to be used with the evaluation modules of the above devices.

Features
  • Easy and fast device programming through EEPROM, I2C
  • Based on Labview
SUPPORT SOFTWARE Download
SCAC119E.ZIP (4405 KB)

Design tools & simulation

SIMULATION TOOLS Download
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Features
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)

CAD/CAE symbols

Package Pins Download
TSSOP (PW) 16 View options

Ordering & quality

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