9DB833
EIGHT OUTPUT DIFFERENTIAL BUFFER FOR PCIE GEN1,2,3
IDT®
EIGHT OUTPUT DIFFERENTIAL BUFFER FOR PCIE GEN1,2,3 14
9DB833 REV H 06/07/16
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 I
REF
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 >200 mV within 300 µs of PD# de-assertion.
