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Programmable System Clock Chip for ATI RS790 - K8 Based Systems

The 9LPRS477 is a main clock synthesizer chip that provides all clocks required for ATI RD7xx-based systems using AMD processors. An SMBus interface allows full control of the device.


  • Features/Benefits
    • CPU, ATIG, SB_SRC and SRC outputs are independently programmable for frequency
    • Spread Spectrum for EMI reduction 
    • Outputs may be disabled via SMBus
    • External crystal load capacitors for maximum frequency accuracy
    • Meets PCIEX Gen2 specifications
    • Meets 30kHz to 33kHz SRC modulation rate specification for USB3.0
  • Key Specifications 
    • CPU outputs cycle-to-cycle jitter < 85ps
    • SRC outputs cycle-to-cycle jitter < 125ps
    • ATIG outputs cycle-to-cycle jitter < 125ps
    • ± 300ppm frequency accuracy on CPU, SRC & ATIG clocks

Product Specification

Chipset ManufacturerChipset NameCore Voltage (V)Input Freq (MHz)Outputs (#)Spread Spectrum
ATI, AMDRS880, RD790, RS790, RS7803.314.32000021Yes

Product Options

Orderable Part IDPart StatusPkg. CodePkg. TypeLead Count (#)Temp. GradePb (Lead) FreeCarrier TypeSample & Buy
9LPRS477CKLFActiveNLG64VFQFPN64CYesTrayCheck Availability
9LPRS477CKLFTActiveNLG64VFQFPN64CYesReelCheck Availability
9LPRS477DKLFActiveNLG64P2VFQFPN64CYesTrayCheck Availability
9LPRS477DKLFTActiveNLG64P2VFQFPN64CYesReelCheck Availability


Technical Documentation

Title Type Format File Size Datesort icon
Datasheets & Errata
9LPRS477D Datasheet Datasheet PDF 353 KB Jan 7, 2015
9LPRS477C Datasheet Datasheet PDF 269 KB Jan 29, 2014
PCN# : TB1504-01R1 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 95 KB Oct 22, 2015
PCN# : TB1504-01 Qty per Reel Standardization for Selective Packages Product Change Notice PDF 50 KB Jul 21, 2015
PCN# : A1311-03R1 Alternate Assembly Locations Product Change Notice PDF 43 KB Feb 16, 2014