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