844002 Datasheet, PDF (1/16 Pages) Integrated Device Technology – Two LVDS outputs

FemtoClock^® Crystal-to-LVDS
Frequency Synthesizer
844002
DATASHEET
GENERAL DESCRIPTION
The 844002 is a 2 output LVDS Synthesizer optimized to generate
Fibre Channel reference clock frequencies. Using a 26.5625MHz
18pF parallel resonant crystal, the following frequencies can be
generated based on the 2 frequency select pins (F_SEL[1:0]):
212.5MHz, 187.5MHz, 159.375MHz, 106.25MHz and 53.125MHz.
The 844002 uses IDT’s 3^rd generation low phase noise VCO
technology and can achieve <1ps typical rms phase jitter, easily
meeting Fibre Channel jitter requirements. The 844002 is packaged
in a small 20-pin TSSOP package.
FEATURES
• Two LVDS outputs
• Selectable crystal oscillator interface
or LVCMOS/LVTTL single-ended input
• Supports the following output frequencies: 212.5MHz,
187.5MHz, 159.375MHz, 106.25MHz and 53.125MHz
• VCO range: 560MHz - 680MHz
• RMS phase jitter @ 212.5MHz, using a 26.5625MHz crystal
(637kHz - 10MHz): 0.65ps (typical)
• Full 3.3V or 2.5V supply modes
• 0°C to 70°C ambient operating temperature
• Available in lead-free (RoHS 6) package
FREQUENCY SELECT FUNCTION TABLE
Input
Frequency
(MHz)
26.5625
26.5625
26.5625
26.5625
23.4375
Inputs
F_SEL1
F_SEL0
M Divider
Value
N Divider
Value
M/N Divider
Value
0
0
24
3
8
0
1
24
4
6
1
0
24
6
4
1
1
24
12
2
0
0
24
3
8
Output
Frequency
(MHz)
212.5 (default)
159.375
106.25
53.125
187.5 (default)
BLOCK DIAGRAM
Pulldown
F_SEL[1:0]
nPLL_SEL ^Pulldown
REF_CLK ^Pulldown
1
26.5625MHz
XTAL_IN
OSC
0
XTAL_OUT
nXTAL_SEL ^Pulldown
2
Phase
Detector
1
VCO
637.5MHz
(w/26.5625MHz
0
Reference)
F_SEL[1:0]
0 0 ÷3
0 1 ÷4
1 0 ÷6
1 1 ÷12
PIN ASSIGNMENT
844002
20-Lead TSSOP
6.5mm x 4.4mm x 0.925mm
package body
G Package
Top View
Q0
nQ0
Q1
nQ1
M = 24 (fixed)
MR ^Pulldown
844002 REVISION B 6/9/15
1
©2015 Integrated Device Technology, Inc.