ICS841S01 Datasheet, PDF (11/16 Pages) Integrated Device Technology – PCI EXPRESS™ CLOCK GENERATOR

ICS841S01
PCI EXPRESS™ CLOCK GENERATOR
RECOMMENDATIONS FOR UNUSED INPUT PINS
INPUTS:
LVCMOS CONTROL PINS
All control pins have internal pull-ups or pull-downs; additional
resistance is not required but can be added for additional
protection. A 1kΩ resistor can be used.
OUTPUT DRIVER CURRENT
The ICS841S01 outputs are HCSL current drive with the cur-
rent
being
set
with
a
resistor
from
I
REF
to
ground.
For
a
50Ω
pc
board trace, the drive current would typically be set with a R_REF
of 475Ω which products an I_REF of 2.32mA. The I_REF is multiplied
by a current mirror to an output drive of 6*2.32mA or 13.92mA.
See Figure 3 for current mirror and output drive details.
I_REF
R_REF
R_L
R_L
FIGURE 3. HCSL CURRENT MIRROR AND OUTPUT DRIVE
PRELIMINARY
IDT^™ / ICS^™ PCI EXPRESS CLOCK GENERATOR
11
ICS841S01BG REV. B MAY 23, 2007