9DB433

FOUR OUTPUT DIFFERENTIAL BUFFER FOR PCIE GEN1–3

IDT®

FOUR OUTPUT DIFFERENTIAL BUFFER FOR PCIE GEN1–3

13

9DB433

MAY 25, 2018

PD#, Power Down

The PD# pin cleanly shuts off all clocks and places the device into a power saving mode. PD# must be asserted before

shutting off the input clock or power to insure an orderly shutdown. PD is asynchronous active-low input for both powering

down the device and powering up the device. When PD# is asserted, all clocks will be driven high, or tri-stated (depending

on the PD# drive mode and Output control bits) before the PLL is shut down.

PD# Assertion

When PD# is sampled low by two consecutive rising edges of DIF#, all DIF outputs must be held High, or tri-stated

(depending on the PD# drive mode and Output control bits) on the next High-Low transition of the DIF# outputs. When the

PD# drive mode bit is set to ‘0’, all clock outputs will be held with DIF driven High with 2 x IREF and DIF# tri-stated. If the

PD# drive mode bit is set to ‘1’, both DIF and DIF# are tri-stated.

PD# De-assertion

Power-up latency is less than 1 ms. This is the time from de-assertion of the PD# pin, or VDD reaching 3.3V, or the time from

valid SRC_IN clocks until the time that stable clocks are output from the device (PLL Locked). If the PD# drive mode bit is

set to ‘1’, all the DIF outputs must driven to a voltage of >200mV within 300µs of PD# de-assertion.