844002AGI www.icst.com/products/hiperclocks.html REV. A JANUARY 16, 2006
1
Integrated
Circuit
Systems, Inc.
ICS844002I
FEMTOCLOCKS™ C RYSTAL-TO-
LVDS FREQUENCY SYNTHESIZER
PRELIMINARY
GENERAL DESCRIPTION
The ICS844002I is a 2 output LVDS Synthesizer
optimized to generate Fibre Channel reference
clock frequencies and is a member of the
HiPerClocks
TM
family of high performance clock
solutions from ICS. Using a 26.5625MHz 18pF
parallel resonant crystal, the following frequencies can be
generated based on the 2 frequency select pins (F_SEL[1:0]):
212.5MHz, 187.5MHz, 159.375MHz, 106.25MHz and
53.125MHz. The ICS844002I uses ICS’ 3
rd
generation
low phase noise VCO technology and can achieve <1ps
typical rms phase jitter, easily meeting Fibre Channel jitter
requirements. The ICS844002I is packaged in a small 20-pin
TSSOP package.
FEATURES
• Two LVDS outputs
• Selectable crystal oscillator interface
or LVCMOS/LVTTL single-ended input
• Supports the following output frequencies: 212.5MHz,
187.5MHz, 159.375MHz, 106.25MHz and 53.125MHz
• VCO range: 560MHz - 680MHz
• RMS phase jitter @ 212.5MHz, using a 26.5625MHz crystal
(637kHz - 10MHz): 0.65ps (typical)
• Full 3.3V or 2.5V supply modes
• -40°C to 85°C ambient operating temperature
• Available in both standard and lead-free RoHS compliant
packages
HiPerClockS™
ICS
11
0
1
0
Phase
Detector
VCO
637.5MHz
(w/26.5625MHz
Reference)
M = 24 (fixed)
F_SEL[1:0]
0 0 ÷3
0 1 ÷4
1 0 ÷6
1 1 ÷12
2
OSC
BLOCK DIAGRAM
stupnI
tuptuO
ycneuqerF
)zHM(
tupnI
ycneuqerF
)zHM(
1LES_F0LES_F
rediviDM
eulaV
rediviDN
eulaV
rediviDN/M
eulaV
5265
.6200423 8 5.212
5265.6201424 6 573.951
5265.6210426 4 52.601
5265.621142212 521.35
5734.3200423 8 5.781
FREQUENCY SELECT FUNCTION TABLE
F_SEL[1:0]
nPLL_SEL
REF_CLK
XTAL_IN
XTAL_OUT
nXTAL_SEL
MR
Q0
nQ0
Q1
nQ1
Pulldown
Pulldown
26.5625MHz
Pulldown
Pulldown
Pulldown
ICS844002I
20-Lead TSSOP
6.5mm x 4.4mm x 0.92mm
package body
G Package
Top View
nc
V
DDO
Q0
nQ0
MR
nPLL_SEL
nc
V
DDA
F_SEL0
V
DD
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
DDO
Q1
nQ1
GND
V
DD
nXTAL_SEL
REF_CLK
XTAL_IN
XTAL_OUT
F_SEL1
PIN ASSIGNMENT
The Preliminary Information presented herein represents a product in prototyping or pre-production. The noted characteristics are based on initial
product characterization. Integrated Circuit Systems, Incorporated (ICS) reserves the right to change any circuitry or specifications without notice.
