ICS844004I-01 Datasheet, PDF (1/12 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO-LVDS FREQUENCY SYNTHESIZER

Integrated
Circuit
Systems, Inc.
PRELIMINARY
ICS844004I-01
FEMTOCLOCKS™ CRYSTAL-TO-
LVDS FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
The ICS844004I-01 is a 4 output LVDS Synthesizer
ICS
optimized to generate Ethernet reference clock
HiPerClockS™ _{frequencies and is a member of the HiPerClocks}TM
family of high performance clock solutions from
ICS. Using a 25MHz 18pF parallel resonant crystal,
the following frequencies can be generated based on the 2
frequency select pins (F_SEL[1:0]): 156.25MHz, 125MHz and
62.5MHz. The ICS844004I-01 uses ICS’ 3^rd generation
low phase noise VCO technology and can achieve <1ps
typical rms phase jitter, easily meeting Ethernet jitter
requirements. The ICS844004I-01 is packaged in a small 24-
pin TSSOP package.
FEATURES
• Four LVDS outputs
• Selectable crystal oscillator interface
or LVCMOS/LVTTL single-ended input
• Supports the following output frequencies: 156.25MHz,
125MHz, 62.5MHz
• VCO range: 560MHz - 680MHz
• RMS phase jitter @ 156.25MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.41ps (typical)
• Full 3.3V or 2.5V supply modes
• -40°C to 85°C ambient operating temperature
FREQUENCY SELECT FUNCTION TABLE
F_SEL1
0
F_SEL0
0
M Divider
Value
25
N Divider
Value
4
M/N Divider
Value
6.25
Output
Frequency
(25MHz Ref.)
156.5
0
1
25
5
5
125
1
0
25
10
2.5
62.5
1
1
25
Not Used
Not Used
BLOCK DIAGRAM
F_SEL[1:0] ^Pulldown
nPLL_SEL ^Pulldown
TEST_CLK ^Pulldown
1
25MHz
XTAL_IN
OSC
0
XTAL_OUT
nXTAL_SEL ^Pulldown
2
Phase
Detector
1
VCO
625MHz
0
(w/25MHz
Reference)
M = 25 (fixed)
MR ^Pulldown
F_SEL[1:0]
0 0 ÷4
0 1 ÷5
1 0 ÷10
1 1 not used
PIN ASSIGNMENT
nQ1 1
Q1 2
VDDo 3
Q0 4
nQ0 5
MR ⁶
nPLL_SEL ⁷
nc ⁸
VDDA ⁹
F_SEL0 ¹⁰
VDD ¹¹
F_SEL1 ¹²
24 nQ2
23 Q2
22 VDDO
21 Q3
20 nQ3
19 GND
18 VDD
17 nXTAL_SEL
16 _{TEST_CLK}
15 _GND
14 _{XTAL_IN}
13 _{XTAL_OUT}
ICS844004I-01
24-Lead TSSOP
4.40mm x 7.8mm x 0.92mm
package body
G Package
Q0
Top View
nQ0
Q1
nQ1
Q2
nQ2
Q3
nQ3
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.
844004AGI-01
www.icst.com/products/hiperclocks.html
REV. A JUNE 15, 2005
1