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Texas Instruments CDCV857B, CDCV857BI Data Handbook / Specifications Guide

Summary

The CDCV857B is a high-performance, low-jitter clock buffer and differential signal driver designed to distribute a single input clock to ten reliable output pairs. Featuring ultra-low skew and advanced power management, this module ensures optimal stability across frequencies ranging from 60 MHz to 200 MHz. The comprehensive manual outlines its crystal-clear operation, detailing technical specifications, functional block diagrams, pin configurations, and low-power modes for electrical engineers developing complex digital systems requiring precise clock distribution solutions.

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查询CDCV857B供应商

SCAS689 − FEBRUARY 2003

Phase-Lock Loop Clock Driver for Double Enters Low-Power Mode When No CLK Data-Rate Synchronous DRAM Input Signal Is Applied or PWRDWN Is Low Applications

Operates From Dual 2.5-V Supplies

Spread Spectrum Clock Compatible

Available in a 48-Pin TSSOP Package or Operating Frequency: 60 MHz to 200 MHz 56-Ball Micro Star Junior BGA Package

Low Jitter (cycle-cycle): ±50 ps Consumes < 100-µA Quiescent Current Low Static Phase Offset: ±50 ps External Feedback Pins (FBIN, FBIN) Are

Used to Synchronize the Outputs to the

Low Jitter (Period): ±35 ps

Input Clocks

Distributes One Differential Clock Input to

Meets/Exceeds the Latest DDR JEDEC

10 Differential Outputs

Spec JESD82−1

description The CDCV857B is a high-performance, low-skew, low-jitter zero delay buffer that distributes a differential clock input pair (CLK, CLK) to 10 differential pairs of clock outputs (Y[0:9], Y[0:9]) and one differential pair of feedback clock outputs (FBOUT, FBOUT). The clock outputs are controlled by the clock inputs (CLK, CLK), the feedback clocks (FBIN, FBIN), and the analog power input (AVDD). When PWRDWN is high, theoutputs switch in phase and frequency with CLK. When PWRDWN is low, all outputs are disabled to a high-impedance state (3-state) and the PLL is shut down (low-power mode). The device also enters this low-power mode when the input frequency falls below a suggested detection frequency that is below 20 MHz (typical 10 MHz). An input frequency detection circuit detects the low frequency condition and, after applying a >20-MHz input signal, this detection circuit turns the PLL on and enables the outputs. When AVDD is strapped low, the PLL is turned off and bypassed for test purposes. The CDCV857B is also able to track spread spectrum clocking for reduced EMI. Since the CDCV857B is based on PLL circuitry, it requires a stabilization time to achieve phase-lock of the PLL. This stabilization time is required following power up. The CDCV857B is characterized for both commercial and industrial temperature ranges.

AVAILABLE OPTIONS

TA TSSOP (DGG) Micro Star Junior BGA (GQL) 0°C to 85°C CDCV857BDGG CDCV857BGQL −40°C to 85°C CDCV857BIGG

FUNCTION TABLE (Select Functions)

INPUTS OUTPUTS PLL

AVDD PWRDWN CLK CLK Y[0:9] Y[0:9] FBOUT FBOUT GND Bypassed/Off GND Bypassed/Off

Off Off

2.5 V (nom) On 2.5 V (nom) On 2.5 V (nom) <20 MHz <20 MHz Off

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

Micro Star Junior is a trademark of Texas Instruments Incorporated.

1POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

Page Summary Contents For Texas Instruments CDCV857B, CDCV857BI Data Handbook / Specifications Guide

Page 1 查询CDCV857B供应商 SCAS689 − FEBRUARY 2003 Phase-Lock Loop Clock Driver for Double Enters Low-Power Mode When No CLK Data-Rate Synchronous DRAM Input Signal Is Applied or PWRDWN Is Low Applications Operate...
Page 2 SCAS689 − FEBRUARY 2003 Micro Star Junior (GQL) Package (TOP VIEW) DGG PACKAGE (TOP VIEW) GND GND Y0 Y5 Y0 Y5 VDDQ VDDQ GND GND NC NC GND GND GND GND GND GND NC NC VDDQ VDDQ VDDQ PWRDWN NC VDDQ PWRDN...
Page 3 SCAS689 − FEBRUARY 2003 functional block diagram PWRDWN Power Down Y1 AVDD and Test Logic Y2 Y2 FBOUT FBOUT 3POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 4 SCAS689 − FEBRUARY 2003 Terminal Functions TERMINAL DESCRIPTION NAME DGG GQL AGND H1 Ground for 2.5-V analog supply AVDD G2 2.5-V Analog supply CLK, CLK 13, 14 F1, F2 Differential clock input FBIN, FB...
Page 5 SCAS689 − FEBRUARY 2003 recommended operating conditions (see Note 4) MIN TYP MAX UNIT VDDQ 2.3 2.7 Supply voltage AVDD VDDQ − 0.12 2.7 CLK, CLK, FBIN, FBIN VDDQ/2 – 0.18 Low-level input voltage, VIL ...
Page 6 SCAS689 − FEBRUARY 2003 electrical characteristics over recommended operating free-air temperature range (unless otherwise noted) (continued) PARAMETER TEST CONDITIONS MIN TYP† MAX UNIT f O = 170 MHz ...
Page 7 SCAS689 − FEBRUARY 2003 PARAMETER MEASUREMENT INFORMATION R = 60 Ω VDD/2 CDCV857B Figure 1. IBIS Model Output Load VDD/2 CDCV857B −VDD/2 SCOPE R = 50 Ω V(TT) C = 14 p F R = 50 Ω V(TT) −VDD/2 V(TT) = G...
Page 8 SCAS689 − FEBRUARY 2003 CDCV857B PROBEC = 14 p F V(TT) V(TT) V(TT) = GND Figure 3. Output Load Test Circuit for Crossing Point Yx, FBOUT Yx, FBOUT tc(n) tc(n+1) tjit(cc) = tc(n) − tc(n+1) Figure 4. Cy...
Page 9 SCAS689 − FEBRUARY 2003 PARAMETER MEASUREMENT INFORMATION CLK (N &gt; 1000 Samples) Figure 5. Phase Offset Yx, FBOUT Yx, FBOUT tsk(o) Figure 6. Output Skew 9POST OFFICE BOX 655303 • DALLAS, TEXAS 7526...
Page 10 SCAS689 − FEBRUARY 2003 PARAMETER MEASUREMENT INFORMATION Yx, FBOUT Yx, FBOUT tc(n) Yx, FBOUT Yx, FBOUT tjit(per) = tcn − f O = Average input frequency measured at CLK/CLK fo Figure 7. Period Jitter Y...
Page 11 PACKAGE OPTION ADDENDUM www.ti.com 4-Mar-2005 PACKAGING INFORMATION Orderable Device Status Package Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Type Drawing Qty CDCV857BDGG ACTIVE TSS...
Page 13 MECHANICAL DATA MTSS003D – JANUARY 1995 – REVISED JANUARY 1998 DGG (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 48 PINS SHOWN 6,00 7,90 0,15 NOM Gage Plane Seating Plane 1,20 MAX PINS ** DIM A MAX 12,60...
Page 14 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and servic...

Manual Details

Brand Texas Instruments
Pages 14
File Size 269.22 KB
Published June 02, 2026
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Frequently Asked Questions

What are the primary outputs distributed by the CDCV857B?

It distributes one differential clock input pair (CLK, CLK) to 10 differential pairs of clock outputs (Y[0:9]) and one feedback output pair (FBOUT, FBOUT).

How can I enter a low-power or disabled state?

Setting PWRDWN low disables all outputs to a high-impedance state, shutting down the PLL. Alternatively, it enters this mode if the input frequency falls below 20 MHz.

Is there a required time after power-up?

Yes, since the CDCV857B utilizes PLL circuitry, it requires a mandatory stabilization time following initial power up to achieve phase-lock.