ICS844251-14 Datasheet, PDF (1/16 Pages) Integrated Device Technology – FEMTOCLOCK™ CRYSTAL-TO-LVDS CLOCK GENERATOR

FEMTOCLOCK™ CRYSTAL-TO-LVDS
CLOCK GENERATOR
General Description
The ICS844251-14 is an Ethernet Clock Generator
ICS
and a member of the HiPerClocks^TM family of high
HiPerClockS™ _{performance devices from IDT. The ICS844251-14}
uses an 18pF parallel resonant crystal over the
range of 23.2MHz – 30MHz. For Ethernet
applications, a 25MHz crystal is used. The device has excellent
<1ps phase jitter performance, over the 1.875MHz – 20MHz
integration range. The ICS844251-14 is packaged in a small 8-pin
TSSOP, making it ideal for use in systems with limited board
space.
ICS844251-14
Features
• One differential LVDS output pair
• Crystal oscillator interface designed for 18pF, parallel resonant
crystal (23.2MHz – 30MHz)
• Output frequency ranges: 145MHz – 187.5MHz and
580MHz – 750MHz
• VCO range: 580MHz – 750MHz
• RMS phase jitter at 156.25MHz, using a 25MHz crystal
(1.875MHz – 20MHz): 0.53ps (typical)
• Full 3.3V or 2.5V output supply modes
• 0°C to 70°C ambient operating temperature
• Available in lead-free (RoHS 6) package
Common Configuration Table
Inputs
Crystal Frequency (MHz) FREQ_SEL
M
25
1
25
26.67
1
25
25 (default)
0
25
Output Frequency Range
N
Multiplication Value M/N
(MHz)
1
25
625
1
25
666.67
4
6.25
156.25
Block Diagram
FREQ_SEL ^Pulldown
XTAL_IN
XTAL_OUT
OSC
Phase
Detector
VCO
580MHz - 750MHz
FREQ_SEL N
0 (default) ÷4
1
÷1
Q
nQ
M = ÷25 (fixed)
Pin Assignment
VDDA 1
GND 2
XTAL_OUT 3
XTAL_IN 4
8 VDD
7Q
6 nQ
5 FREQ_SEL
ICS844251-14
8 Lead TSSOP
4.40mm x 3.0mm x 0.925mm
package body
G Package
Top View
IDT™ / ICS™ LVDS CLOCK GENERATOR
1
ICS844251BG-14 REV. A MAY 1, 2009