9FG830

IDT®

Eight Output Differential Frequency Generator for PCIe Gen3 and QPI

1680E—04/04/17

Eight Output Differential Frequency Generator

for PCIe Gen3 and QPI

1

DATASHEET

General Description:

The 9FG830 is a Frequency Timing Generator that provides 8

HCSL differential output pairs. These outputs support PCI-Express

Gen3, and QPI applications. The part supports Spread Spectrum

and synthesizes several additional output frequencies from either

a 14.31818 MHz crystal, a 25 MHz crystal or reference input clock.

The 9FG830 also outputs a copy of the reference clock. Complete

control of the device is available via strapping pins or via the

SMBus interface.

Recommended Application:

8 Output Differential Output Frequency Generator for PCIe Gen3

and QPI

Output Features:

•

8 - 0.7V current mode differential HCSL output pairs

•

1 - 3.3V LVTTL REF output

Features/Benefits:

•

Pin-to-Pin with 9FG108D; Easy upgrade to PCIe Gen3

•

Generates common frequencies from 14.318 MHz or 25

MHz; single part supports mulitple applications

•

Provides copy of reference output; eleminates need for

additional crystal or oscillator

•

Three spread spectrum modes: -0.5%, +/-0.25%, and off;

EMI reduction

•

Unused outputs may be disabled in Hi-Z; save system

power

•

Device may be configured by SMBus and/or strap pins;

can be used in systems without SMBus

Key Specifications:

•

Cycle-to-cycle jitter: < 50ps with 25MHz input

•

Output-to-output skew: <50ps

•

Phase jitter: PCIe Gen3 < 1ps rms

•

Phase jitter: QPI 9.6GB/s < 0.2ps rms

•

10 ppm synthesis error with 25MHz input and Spread Off

Functional Block Diagram

STOP

LOGIC

XIN/CLKIN

X2

DIF(7:0)

CONTROL

LOGIC

SPREAD

FS(2:0)

SDATA

SCLK

SEL14M_25M#

DIF_STOP#

PROGRAMMABLE

SPREAD PLL

8

IREF

OSC

REFOUT

OE(7:0)