ICS843004-01 Datasheet, PDF (1/15 Pages) Integrated Circuit Systems – FEMTOCLOCKS-TM CRYSTAL-TO- 3.3V LVPECL FREQUENCY SYNTHESIZER

Integrated
Circuit
Systems, Inc.
ICS843004-01
FEMTOCLOCKS™ CRYSTAL-TO-
3.3V LVPECL FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
The ICS843004-01 is a 4 output LVPECL
ICS
synthesizer optimized to generate Ethernet
HiPerClockS™ _{reference clock 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 settings of 2 frequency select pins (F_SEL[1:0]):
156.25MHz, 125MHz, 62.5MHz. The ICS843004-01 uses
ICS’ 3^rd generation low phase noise VCO technology and can
achieve 1ps or lower typical rms phase jitter, easily meeting
Ethernet jitter requirements. The ICS843004-01 is packaged
in a small 24-pin TSSOP package.
FEATURES
• Four 3.3V LVPECL outputs
• Selectable crystal oscillator interface
or LVCMOS/LVTTL single-ended input
• Supports the following output frequencies:
156.25MHz, 125MHz and 62.5MHz
• VCO range: 560MHz - 680MHz
• RMS phase jitter @ 156.25MHz, using a 25MHz crystal
(1.875MHz - 20MHz): 0.57ps (typical)
• RMS phase noise at 156.25MHz (typical)
Phase noise:
Offset
Noise Power
100Hz ............... -95.5 dBc/Hz
1KHz ................ -118 dBc/Hz
10KHz ................ -126 dBc/Hz
100KHz .............. -126.6 dBc/Hz
• Full 3.3V supply mode
• -30°C to 85°C ambient operating temperature
FREQUENCY SELECT FUNCTION TABLE
F_SEL1
0
F_SEL0
0
Inputs
M Divider N Divider
Value
Value
25
4
M/N
Divider Value
6.25
Output Frequency
(25MHz Ref.)
156.25
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
(w/25MHz
0
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
VCCo 3
Q0 4
nQ0 5
MR ⁶
nPLL_SEL ⁷
nc 8
VCCA ⁹
F_SEL0 ¹⁰
VCC ¹¹
F_SEL1 ¹²
24 nQ2
23 Q2
2 2 VCCO
21 Q3
20 nQ3
19 VEE
18 VCC
17 nXTAL_SEL
16 _{TEST_CLK}
15 _VEE
14 _{XTAL_IN}
13 _{XTAL_OUT}
ICS843004-01
24-Lead TSSOP
4.40mm x 7.8mm x 0.92mm
package body
G Package
Q0
Top View
nQO
Q1
nQ1
Q2
nQ2
Q3
nQ3
843004AG-01
www.icst.com/products/hiperclocks.html
1
REV. B MAY 6, 2005