MK2771-15 Datasheet, PDF (1/4 Pages) Integrated Circuit Systems – VCXO and Set-Top Clock Source

MK2771-15
VCXO and Set-Top Clock Source
Description
The MK2771-15 is a low cost, low jitter, high
performance VCXO and clock synthesizer
designed for set-top boxes. The on-chip Voltage
Controlled Crystal Oscillator accepts a 0 to 3V
input voltage to cause the output clocks to vary by
±100 ppm. Using ICS/MicroClock’s patented
VCXO and analog Phase-Locked Loop (PLL)
techniques, the device uses an inexpensive
13.5 MHz pullable crystal input to produce
multiple output clocks including two selectable
processor clocks, a selectable audio clock, two
communications clocks, and three fixed clocks. All
clocks are frequency locked to the 27.00MHz
output (and to each other) with zero ppm error, so
any output can be used as the VCXO output.
Features
• Packaged in 28 pin SSOP (QSOP)
• Ideal for systems using Oak’s MPEG decoders
• On-chip patented VCXO with pull range
of 200ppm
• VCXO tuning voltage of 0 to 3 V
• Processor frequencies include 33.3, 40, 50, 66.6,
81, and 100 MHz
• Audio clocks of 8.192 MHz, 11.2896 MHz,
12.288 MHz and 18.432 MHz
• Zero ppm synthesis error in all clocks (all exactly
track 27 MHz VCXO)
• Uses an inexpensive 13.5 MHz pullable crystal
• Full CMOS output swings with 25 mA output
drive capability at TTL levels
• Advanced, low power, sub-micron CMOS process
• 5 V operating voltage with 3.3 V capable I/O
Block Diagram
VDD GND
VDDIO
PCS2:0
3
ACS1:0
2
SC
VIN
13.5 MHz X1
Voltage
pullable
Controlled
crystal
Crystal
X2 Oscillator
Output
Buffers
2
Processor Clocks
Clock
Synthesis
Circuitry
Output
Buffer
Audio Clock
Output
Buffers
2
Comm. Clocks
Output
Buffer
54.00 MHz
÷ 2 ^Output
Buffer
27.000 MHz
÷2
Output
Buffer
13.500 MHz
MDS 2771-15 E
1
Revision 122899
Printed 11/16/00
Integrated Circuit Systems, Inc.• 525 Race Street • San Jose • CA • 95126 •[phone]tel• www.icst.com