ICS841664I Datasheet, PDF (1/16 Pages) Integrated Device Technology – FEMTOCLOCK™ CRYSTAL-TO-HCSL CLOCK GENERATOR

PRELIMINARY
FEMTOCLOCK™ CRYSTAL-TO-HCSL
CLOCK GENERATOR
GENERAL DESCRIPTION
The ICS841664I is an optimized sRIO clock
ICS
generator and member of the HiPerClocks™ family
HiPerClockS™ _{of high-perfor mance clock solutions from IDT.}
The device uses a 25MHz parallel crystal to gen-
erate 125MHz and 156.25MHz clock signals,
replacing solutions requiring multiple oscillator and fanout buffer
solutions. The device has excellent phase jitter (< 1ps rms) suit-
able to clock components requiring precise and low-jitter sRIO
clock signals. Designed for telecom, networking and industrial
applications, the ICS841664I can also drive the high-speed
sRIO SerDes clock inputs of communication processors, DSPs,
switches and bridges.
ICS841664I
FEATURES
• Four differential HCSL clock outputs: configurable for sRIO
(125MHz or 156.25MHz) 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:
125MHz or 156.25MHz
• VCO: 625MHz
• PLL bypass and output enable
• RMS phase jitter, using a 25MHz crystal (1.875MHz - 20MHz):
0.35ps (typical) @ 125MHz
• 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 = 625MHz
M = ÷25
÷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
ICS841664I
28-Lead TSSOP
6.1mm x 9.7mm x 0.925mm
package body
G Package
Top View
The Preliminary Information presented herein represents a product in pre-production. The noted characteristics are based on initial product characterization
and/or qualification. Integrated Device Technology, Incorporated (IDT) reserves the right to change any circuitry or specifications without notice.
IDT^™ / ICS^™ HCSL CLOCK GENERATOR
1
ICS841664AGI REV. A JANUARY 30, 2009