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1523 - Block Diagram
1523 - Pinout


Video Clock Synthesizer With I2C Programmable Delay

The 1523 is a low-cost, high-performance frequency generator. It is well suited to general purpose phase controlled clock synthesis as well as line-locked and genlocked high-resolution video applications. Using IDT's advanced low-voltage CMOS mixed-mode technology, the 1523 is an effective phase controlled clock synthesizer and also supports video projectors and displays at resolutions from VGA to beyond UXGA. The 1523 offers clock outputs in both differential (to 250 MHz) and single-ended (to 150 MHz) formats. Dynamic Phase Adjust (DPA) allows I2C™ control of the output clock's phase relative to the input sync signal. A second, half speed set of outputs that can be separately enabled allows such applications as clocking analog-to-digital converters. The FUNC pin provides either the regenerated input from the phase-locked loop (PLL) divider chain output, or the input HSYNC after being sharpened by the Schmitt trigger. Both signals are then delayed by the DPA. The advanced PLL uses either its internal programmable feedback divider or an external divider. Either the internal or external loop filters is software selectable. The COAST input pin disables the PLL's charge pump, causing the device to idle at the current speed for short periods of time, such as vertical blanking intervals. The device is programmed by a standard I2C-bus serial interface and is available in a 24-pin, wide small-outline integrated circuit (SOIC) package.


  • Low Jitter
  • Wide input frequency range
  • 15.734 kHz to 100 MHz
  • PECL differential outputs
  • Up to 250 MHz
  • SSTL_3 Single-ended clock outputs
  • Up to 150 MHz
  • Dynamic Phase Adjust (DPA) for all outputs
  • I2C controlled phase adjustment
  • Full clock cycle down to 1/64 of a clock
  • Double-buffered control registers
  • External or internal loop filter selection
  • COAST input can disable charge pump
  • 3.3 VDD
  • 5 volt Tolerant Inputs
  • Industry Standard I2C-bus programming interface
  • PLL Lock detection via I2C or LOCK/REF output pin
  • 24-pin 300-mil SOIC package

Product Specification

Outputs (#)Output TypeOutput Freq Range (MHz)Input Freq (MHz)Inputs (#)Input TypeOutput Banks (#)Core Voltage (V)Output Voltage (V)
5SSTL, LVPECL0.000000 - 250.0000000.015734 - 100.0000002LVCMOS53.33.3

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
1523MLFLast Time BuyPSG24SOIC24CYesTubeCheck Availability
1523MLFTLast Time BuyPSG24SOIC24CYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
1523 Datasheet Datasheet PDF 241 KB Feb 8, 2011
Apps Notes & White Papers
1523 Demo Board Schematics Application Note PDF 45 KB Sep 11, 2006
PDN# : MM-15-05 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 531 KB Nov 13, 2015
PCN# : A1309-01 Changed of Traceability Mark Format Product Change Notice PDF 439 KB Oct 11, 2013
PCN# : TB1303-02 Change of Tape & Reel Packing Method for Selective Products Product Change Notice PDF 361 KB Mar 24, 2013
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PCN# : A1208-01R1 Gold to Copper Wire Product Change Notice PDF 254 KB Dec 21, 2012
PCN# : A1208-06 Changed of Assembly Location and Crystal Product Change Notice PDF 1.06 MB Nov 18, 2012
PCN# A-0607-06 MMT Thailand as Alternate Assembly Facility for PLCC, SOIC 150mil/300mil Product Change Notice PDF 223 KB Oct 6, 2006
1523 Register Tools Misc ZIP 4 KB Sep 20, 2006

Software & Tools

Title Type Format File Size Datesort icon
1523 IBIS Model - IBIS ZIP 9 KB Nov 6, 2012