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ICS841654I Datasheet, PDF (1/17 Pages) Integrated Device Technology – FEMTOCLOCKS™ CRYSTAL-TO-HCSL CLOCK GENERATOR
FEMTOCLOCKS™ CRYSTAL-TO-HCSL
CLOCK GENERATOR
GENERAL DESCRIPTION
The ICS841654I is an optimized PCIe and sRIO clock
ICS
generator and member of the HiPerClocks™ family
HiPerClockS™ of high-performance clock solutions from IDT. The
device uses a 25MHz parallel crystal to generate
100MHz and 125MHz clock signals, replacing
solutions requiring multiple oscillator and fanout buffer solutions.
The device has excellent phase jitter (< 1ps rms) suitable to clock
components requiring precise and low-jitter PCIe or sRIO or both
clock signals. Designed for telecom, networking and industrial
applications, the ICS841654I can also drive the high-speed sRIO
and PCIe SerDes clock inputs of communication processors,
DSPs, switches and bridges.
ICS841654I
FEATURES
• Four differential HCSL clock outputs: configurable for PCIe
(100MHz) and sRIO (100MHz or 125MHz) clock signals
One REF_OUT LVCMOS/LVTTL clock output
• Selectable crystal oscillator interface, 25MHz, 18pF parallel
resonant crystal or LVCMOS/LVTTL single-ended reference
clock input
• Supports the following output frequencies:
100MHz or 125MHz
• VCO: 500MHz
• PLL bypass and output enable
• RMS phase jitter at 100MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.44ps (typical)
• Full 3.3V power supply mode
• -40°C to 85°C ambient operating temperature
• Available in both standard (RoHS 5) and lead-free (RoHS 6)
packages
BLOCK DIAGRAM
XTAL_IN
XTAL_OUT
OSC 0
REF_IN Pulldown
1
REF_SEL Pulldown
IREF
BYPASS Pulldown
FSEL[0:1] Pulldown
MR/nOE Pulldown
1
FemtoClock
PLL
0
÷NA
VCO = 500MHz
M = ÷20
÷NB
nREF_OE Pullup
QA0
nQA0
QA1
nQA1
QB0
nQB0
QB1
nQB1
REF_OUT
PIN ASSIGNMENT
VDD 1
REF_OUT 2
GND 3
QA0 4
nQA0 5
VDDOA 6
GND 7
QA1 8
nQA1 9
nREF_OE 10
BYPASS 11
REF_IN 12
REF_SEL 13
VDDA 14
28 IREF
27 FSEL0
26 FSEL1
25 QB0
24 nQB0
23 VDDOB
22 GND
21 QB1
20 nQB1
19 MR/nOE
18 VDD
17 XTAL_IN
16 XTAL_OUT
15 GND
ICS841654I
28-Lead TSSOP
6.1mm x 9.7mm x 0.925mm
package body
G Package
Top View
IDT™ / ICS™ HCSL CLOCK GENERATOR
1
ICS841654AGI REV. A APRIL 17, 2008