ICS840004I-01 Datasheet, PDF (1/16 Pages) Integrated Circuit Systems – FEMTOCLOCKS™ CRYSTAL-TO LVCMOS/LVTTL FREQUENCY SYNTHESIZER

ICS840004I-01
FEMTOCLOCKS™ CRYSTAL-TO-
LVCMOS/LVTTL FREQUENCY SYNTHESIZER
GENERAL DESCRIPTION
FEATURES
The ICS840004I-01 is a 4 output LVCMOS/LVTTL
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 IDT. Using a 25MHz, 18pF
parallel resonant crystal, the following frequencies can be
generated based on the 2 frequency select pins (F_SEL1:0):
156.25MHz, 125MHz, and 62.5MHz. The ICS840004I-01 uses
IDT’s 3^rd generation low phase noise VCO technology and can
achieve 1ps or lower typical random rms phase jitter, easily
meeting Ethernet jitter requirements. The ICS840004I-01 is
packaged in a small 20-pin TSSOP package.
• Four LVCMOS/LVTTL outputs,
17Ω typical output impedance
• Selectable crystal oscillator interface
or LVCMOS single-ended input
• Supports the following output frequencies: 156.25MHz,
125MHz and 62.5MHz
• VCO range: 560MHz - 700MHz
• RMS phase jitter @ 156.25MHZ (1.875MHz - 20MHz):
0.52ps (typical)
• Output supply modes:
Core/Output
3.3V/3.3V
3.3V/2.5V
2.5V/2.5V
• -40°C to 85°C ambient operating temperature
• Available in both standard (RoHS 5) and lead-free RoHS
(6) packages
FREQUENCY SELECT FUNCTION TABLE
F_SEL1
0
F_SEL0
0
Inputs
M Divider N Divider
Value
Value
25
4
0
1
25
5
1
0
25
10
1
1
25
5
M/N
Ratio Value
6.25
5
2.5
5
Output Frequency (MHz)
(25MHz Ref.)
156.25
125
62.5
125 (default)
BLOCK DIAGRAM
OE ^Pullup
F_SEL1:0 ^{Pullup:Pullup}
nPLL_SEL ^Pulldown
nXTAL_SEL ^Pulldown
XTAL_IN ^25MHz
OSC ⁰
XTAL_OUT
REF_CLK ^Pulldown
1
2
Phase
Detector
VCO
F_SEL1:0
1
N
0 0 ÷4
0 1 ÷5
0
1 0 ÷10
1 1 ÷5 (default)
M = ÷25 (fixed)
PIN ASSIGNMENT
F_SEL0 1 20 F_SEL1
nc ^{2 19} GND
nXTAL_SEL ^{3 18} Q0
REF_CLK ^{4 17} Q1
OE ⁵
1 6 _VDDO
MR ^{6 15} Q2
nPLL_SEL ^{7 14} Q3
VDDA ⁸
13 _GND
nc ^{9 12} XTAL_IN
Q0
VDD ^{10 11} XTAL_OUT
ICS840004I-01
Q1
20-Lead TSSOP
6.5mm x 4.4mm x 0.92mm
Q2
package body
G Package
Q3
Top View
MR ^Pulldown
840004AGI-01
1
REV. A OCTOBER 22, 2007