ICS841S02BGILF datasheet(12/17 Pages) IDT

12 / 17 page

IDT™ / ICS™ PCI EXPRESS CLOCK GENERATOR

ICS841S02BGI REV. C NOVEMBER 1, 2007

ICS841S02I

PCI EXPRESS™ CLOCK GENERATOR

PRELIMINARY

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 1k

Ω resistor can be used.

RECOMMENDATIONS FOR UNUSED INPUT AND OUTPUT PINS

OUTPUTS:

HCSL OUTPUTs

All unused HCSL outputs can be left floating. We recommend

that there is no trace attached. Both sides of the differential output

pair should either be left floating or terminated.

OUTPUT DRIVER CURRENT

The ICS841S02I 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 475

Ω which products an I

REF of 2.32mA. The IREF 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.

FIGURE 3. HCSL CURRENT MIRROR AND OUTPUT DRIVE

IREF

RREF

ICS841S02BGILF Datasheet(PDF) 12 Page - Integrated Device Technology