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