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 Options

Orderable Part ID Part Status Pkg. Type Lead Count (#) Temp. Grade Pb (Lead) Free Carrier Type Buy Sample
Obsolete SOIC 24 C Yes Tube
Obsolete SOIC 24 C Yes Reel

Documentation & Downloads

Title Other Languages Type Format File Size Date
Datasheets & Errata
1523 Datasheet Datasheet PDF 241 KB
Application Notes & White Papers
1523 Demo Board Schematics Application Note PDF 45 KB
PDN# : MM-15-05 PRODUCT DISCONTINUANCE NOTICE Product Discontinuation Notice PDF 531 KB
PCN# : A1309-01 Changed of Traceability Mark Format Product Change Notice PDF 439 KB
PCN# : TB1303-02 Change of Tape & Reel Packing Method for Selective Products Product Change Notice PDF 361 KB
PCN# : A1208-01R1 Gold to Copper Wire Product Change Notice PDF 254 KB
PCN# : A1208-06 Changed of Assembly Location and Crystal Product Change Notice PDF 1.06 MB
PCN# A-0607-06 MMT Thailand as Alternate Assembly Facility for PLCC, SOIC 150mil/300mil Product Change Notice PDF 223 KB
1523 IBIS Model - IBIS ZIP 9 KB
1523 Register Tools Misc ZIP 4 KB