PRELIMINARY
ICS844003I-01
Integrated
Circuit
Systems, Inc.
FEMTOCLOCKS™ C RYSTAL-TO-LVDS
FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
FEATURES
The ICS844003I-01 is a 3 differential output LVDS
• Three LVDS outputs on two banks, A Bank with one LVDS
pair and B Bank with 2 LVDS output pairs
ICS
Synthesizer designed to generate Ethernet refer-
ence clock frequencies and is a member of the
HiPerClocks™family of high performance clock
solutions from ICS. Using a 19.53125MHz or
HiPerClockS™
• Using a 19.53125MHz or 25MHz crystal, the two output
banks can be independently set for 625MHz, 312.5MHz,
156.25MHz or 125MHz
25MHz, 18pF parallel resonant crystal, the following frequen-
cies can be generated based on the settings of 4 frequency
select pins (DIV_SEL[A1:A0], DIV_SEL[B1:B0]): 625MHz,
312.5MHz, 156.25MHz, and 125MHz. The 844003I-01 has 2
output banks, Bank A with 1 differential LVDS output pair and
Bank B with 2 differential LVDS output pairs.
• Selectable crystal oscillator interface or LVCMOS/LVTTL
single-ended input
• VCO range: 490MHz to 680MHz
• RMS phase jitter @ 156.25MHz (1.875MHz - 20MHz):
0.56ps (typical)
The two banks have their own dedicated frequency select • 3.3V output supply mode
pins and can be independently set for the frequencies men-
• -40°C to 85°C ambient operating temperature
tioned above. The ICS844003I-01 uses ICS’ 3rd generation
low phase noise VCO technology and can achieve 1ps or
lower typical rms phase jitter, easily meeting Ethernet jitter
requirements. The ICS844003I-01 is packaged in a small
24-pin TSSOP package.
PIN ASSIGNMENT
1
2
3
DIV_SELB0
VCO_SEL
MR
24
23
22
DIV_SELB1
VDDO_B
QB0
4
5
6
7
VDDO_A
nQB0
21
20
19
18
17
16
15
14
13
QA0
nQA0
CLK_ENB
CLK_ENA
FB_DIV
QB1
nQB1
XTAL_SEL
TEST_CLK
XTAL_IN
XTAL_OUT
GND
8
9
10
11
12
VDDA
VDD
DIV_SELA1
DIV_SELA0
ICS844003I-01
24-LeadTSSOP
BLOCK DIAGRAM
4.40mm x 7.8mm x 0.92mm
Pullup
CLK_ENA
package body
G Package
TopView
Pullup
DIV_SELA[1:0]
Pullup
VCO_SEL
QA0
0 0 ÷1
nQA0
Pulldown
0 1 ÷2
TEST_CLK
XTAL_IN
0
1
0
1
1 0 ÷3
1 1 ÷4 (default)
Phase
Detector
VCO
OSC
XTAL_OUT
XTAL_SEL
QB0
Pullup
FB_DIV
0 0 ÷2
nQB0
0 1 ÷4
0 = ÷25 (default)
1 = ÷32
1 0 ÷5
QB1
1 1 ÷8 (default)
Pulldown
Pullup
FB_DIV
DIV_SELB[1:0]
MR
nQB1
Pulldown
Pullup
CLK_ENB
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.
844003AGI-01
www.icst.com/products/hiperclocks.html
REV. A MAY 31, 2005
1