19-Output Differential Zbuffer for PCIe Gen2/3
and QPI
9ZX21901C
DATASHEET
General Description
Features/Benefits
The 9ZX21901 is Intel DB1900Z Differential Buffer suitable for
PCI-Express Gen3 or QPI applications. The part is backwards
compatible to PCIe Gen1 and Gen2. A fixed external feedback
maintains low drift for critical QPI applications. In bypass
mode, the 9ZX21901 can provide outputs up to 400MHz.
• Fixed feedback path/ 0ps input-to-output delay
• 9 Selectable SMBus addresses; Multiple devices can share
same SMBus segment
• 8 dedicated OE# pins; hardware control of outputs
• PLL or bypass mode; PLL can dejitter incoming clock
• Selectable PLL BW; minimizes jitter peaking in downstream
Recommended Application
• 19-output PCIe Gen3/QPI buffer with fixed feedback for
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Romley platforms
Output Features
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• 19 – 0.7V current mode differential HCSL output pairs
Key Specifications
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PLL's
Spread spectrum compatible; tracks spreading input clock
for EMI reduction
SMBus Interface; unused outputs can be disabled
100MHz & 133.33MHz PLL mode; legacy QPI support
Undriven differential outputs in Power Down mode for
maximum power savings
Cycle-to-cycle jitter: < 50ps
Output-to-output skew:
