General Description

The 9LPRS477D 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.

Recommended Application

ATI RS780/RS790/RD790/RS880 systems using AMD K8

processors

Output Features

? 2 - Greyhound compatible K8 CPU pairs

? 6 - low-power differential SRC pairs

? 2 - low-power differential SouthBridge SRC pairs

? 4 - low-power differential ATIG pairs

? 1 - Selectable low-power differential 100MHz non-spread

SATA/ SRC output

? 1 - Selectable 100MHz low-power differential/ 66 MHz

single-ended HTT clock

? 2 - 48MHz USB clocks

? 3 - 14.318MHz Reference clocks

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