873990AY

www.icst.com/products/hiperclocks.html

REV. B

JUNE 13, 2005

1

Integrated

Circuit

Systems, Inc.

ICS873990

The ICS873990 is a low voltage, low skew, 3.3V

LVPECL/ECL Clock Generator and a member

of the HiPerClockS™ family of High Performance

Clock Solutions from ICS. The ICS873990 has

two selectable clock inputs. The XTAL1 and

XTAL2 are used to interface to a crystal and the TEST_CLK

pin can accept a LVCMOS or LVTTL input. This device has a

fully integrated PLL along with frequency configurable out-

puts. An external feedback input and output regenerates

clocks with “zero delay”.

The four independent banks of outputs each have their own

output dividers, which allow the device to generate a multi-

tude of different bank frequency ratios and output-to-input

frequency ratios. The output frequency range is 25MHz to

400MHz and the input frequency range is 6.25MHz to

125MHz. The PLL_SEL input can be used to bypass the PLL

for test and system debug purposes. In bypass mode, the

input clock is routed around the PLL and into the internal out-

put dividers.

The ICS873990 also has a SYNC output which can be used

for system synchronization purposes. It monitors Bank A and

Bank C outputs for coincident rising edges and signals a pulse

per the timing diagrams in this data sheet. This feature is used

primarily in applications where Bank A and Bank C are run-

ning at different frequencies, and is particularly useful when

they are running at non-integer multiples of each other.

Example Applications:

1. Line Card Multiplier: Multiply 19.44MHz from a back-plane

to 77.76MHz on the line card ASIC and Serdes.

2. Zero Delay Buffer: Fan out up to thirteen 100MHz copies

from a reference clock to multiple processing units on an

embedded system.

• 14 differential LVPECL outputs

• Selectable crystal oscillator interface or TEST_CLK inputs

• TEST_CLK accepts the following input levels:

LVCMOS, LVTTL

• Output frequency: 400MHz (maximum)

• Crystal input frequency range: 10MHz to 25MHz

• VCO range: 200MHz to 800MHz

• Output skew: 250ps (maximum)

• Cycle-to-cyle jitter: ±50ps (typical)

• LVPECL mode operating voltage supply range:

V

• ECL mode operating voltage supply range:

V

• 0°C to 70°C ambient operating temperature

• Industrial temperature available upon request

• Lead-Free package fully RoHS compliant

HiPerClockS™

ICS

52-Lead LQFP

10mm x 10mm x 1.4mm package body

Y package

Top View

nQB3

QB3

nQA0

QA0

nQA1

QA1

nQA2

QA2

nQA3

QA3

SYNC_SEL

VCO_SEL

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QC1

nQC1

QC0

nQC0

QD1

nQD1

QD0

nQD0

QFB

nQFB

ICS873990