MK2771-13
VCXO and Set-Top Clock Source
Description
Features
The MK2771-03 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 crystal input to produce multiple
output clocks including a selectable processor
clock, a selectable audio clock, a fixed 33.33 MHz
or 24.576 MHz, two low skew copies of the
27MHz, and a fixed 13.5 MHz. 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.
• Packaged in 20 pin SOIC
• Pin for pin and functional upgrade to MK2771-03
• Ideal for systems using Oak’s MPEG decoders
• On-chip patented VCXO with pull range
of 200ppm
• VCXO tuning voltage of 0 to 3V
• Processor frequency of 16.67 MHz, 20 MHz,
25 MHz, 32 MHz, 40 MHz, or 50 MHz
• Audio clocks of 8.192, 11.2896, and 12.288 MHz
• Zero ppm synthesis error in all clocks (all exactly
track 27MHz VCXO) - patented
• Uses an inexpensive 13.5 MHz crystal
• 25mA output drive capability at TTL levels
• Advanced, low power, sub-micron CMOS process
• 5V operating voltage
This chip directly replaces the MK2771-03 when a
13.5 MHz input crystal is substituted for the
14.31818 MHz used on the -03. Additionally, the
-13 adds 25 MHz to the processor clock selection,
and 24.576 MHz on the BCLK.
VDD GND
Block Diagram
3
3
2
Output
PCS1:0
ACS1:0
Processor Clock
Buffer
2
Output
Audio Clock
Buffer
Clock
Synthesis
Circuitry
BCS
VIN
Output
Buffer
33.3 MHz or
24.576 MHz
2
13.5 MHz
pullable
crystal
X1
X2
Output
Buffers
Voltage
Controlled
Crystal
27.000 MHz
13.500 MHz
Output
Buffer
÷ 2
Oscillator
MDS 2771-13 A
1
Revision 110298
Printed 11/16/00
Integrated Circuit Systems • 525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com