Overview

The 94228 is a main clock synthesizer chip for AMD-K7 based systems with VIA style chipset. This provides all clocks required for such a system. The 94228 employs serial programming I2C interface as a vehicle for changing output functions, changing output frequency, configuring output strength, configuring output-to-output skew, changing spread spectrum amount, changing group divider ratio, and disabling/enabling individual clocks. This device also has propriety watchdog timer technology which will reset the frequency to a safe setting if the system becomes unstable from over-clocking.

94228 - Block Diagram
94228 - Pinout
94228 - Block Diagram
94228 - Pinout
  • 1 - Differential pair open drain CPU clocks at 2.7V
  • 1 - Differential pair push-pull CPU clocks at 2.5V
  • 11 - PCI including 1 free running and 1 early at 3.3V
  • 1 - 48MHz, at 3.3V fixed
  • 1 - 24/48MHz at 3.3V
  • 3 - REF at 3.3V, 14.318MHz
  • Programmable output frequency
  • Programmable output rise/fall time
  • Programmable slew and skew control for CPUCLK, PCICLK, AGP, REF, 48MHz, and 24_48MHz
  • Real-time system reset output
  • Spread spectrum for EMI control typically by 7dB to 8dB, with programmable spread percentage
  • Watchdog timer technology to reset the system if over-clocking causes malfunction
  • Uses an external 14.318MHz crystal

Documentation
Type Title Date
Product Change Notice
PCN# : TB1303-02 Change of Tape & Reel Packing Method for Selective Products
PDF 361 KB
1 item

Design & Development

ECAD Models

Schematic symbols, PCB footprints, and 3D CAD models from SamacSys can be found by clicking on products in the Product Options table. If a symbol or model isn't available, it can be requested directly from the website.

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Product Options

    Processing table
    Pkg. Type
    Lead Count (#)
    Temp. Grade
    Pb (Lead) Free
    Carrier Type
    Buy / Sample
    Part Number
    94228BFLFT
    circleObsolete
    memory
    view_in_ar
    		SSOP 48 C Yes Reel
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