PECL Clock Synthesizer - Integrated Circuit Systems
Description
ICS507-01/02 PECL Clock Synthesizer
Description
The ICS507-01 and ICS507-02 are inexpensive ways to generate a low jitter 155.
52 MHz (or other high speed) differential PECL clock output from a low frequency crystal input.
Using Phase-LockedLoop (PLL) techniques, the devices use a standard fundamental mode crystal to produce output clocks up to 200 MHz.
Stored in each chip’s ROM is the ability to generate a selection of different multiples of the input reference frequency, including an exact 155.
52 MHz clock from common crystals.
For lowest jitter and phase noise on a 155.
52 MHz clock, a 19.
44 MHz crystal and the x8 selection can be used.
Features
• Packaged as 16 pin narrow SOIC or die • Input crystal frequency of 5 - 27 MHz • Input clock frequency of 5 - 52 MHz • Uses low-cost crystal • Differential PECL output clock frequencies up to 200 MHz • Duty cycle of 49/51 • 3.
3 V or 5.
0 V±10% operating supply • Ideal for SONET applications and oscillator manufacturers • Advanced, low power CMOS process • Industrial temperature versions available
Block Diagram
GND
VDD
1.
1kΩ RES
S0:1
2 Clock Synthesis and Control Circuitry
Clock Buffer/ Crystal Oscillator
Output Buffer
270 Ω
PECL
62 Ω VDD 62 Ω
Crystal or clock
X1
Output Buffer
PECL
270 Ω
X2
Output resistor values shown are for unterminated lines.
Refer to MAN09 for additional information.
Output Enable (both outputs)
1 Revision 042600 Printed 11/13/00 Integrated Circuit Systems, Inc.
• 525 Race Street • San Jose •CA •95126• (408)295-9800tel • www.
icst.
com
MDS 507 C
ICS507-01/02 PECL Clock Synthesizer
Pin Assignment ICS507-01/02
X1/ICLK VDD VDD S1 GND GND NC PECL 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 X2 NC S0 OE NC NC RES PECL
Clock Multiplier Select Table
S1 0 0 0 M M M 1 1 1 S0 0 M 1 0 M 1 0 M 1 Multiplier 9.
72X* 10X 12X 6.
25X 8X 5X 2X 3X 4X
*Use this selection to get 155.
52 MHz from a 16 MHz input.
For lowest phase noise generation of 155.
52 MHz, use a 19.
44 MHz crystal and the 8X selection.
16 pin n...
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