
MK3754
MDS 3754 H
1
Revision 072805
Integrat ed Circuit Systems ● 525 Race Stre et, San Jo se, CA 9 5126 ● te l (40 8 ) 2 97-12 01 ● www.ics t.co m
LOW COST 54 MHZ 3.3 VOLT VCXO
Description
The MK3754D and MK3754B are drop-in replacements
for the MK3754S device. Compared to these earlier
devices the MK3754D and MK3754B offer a wider
operating frequency range and improved power supply
noise rejection.
The MK3754 is ICS’ lowest cost, low jitter, high
performance 3.3 Volt VCXO and PLL clock synthesizer
designed to replace expensive 54 MHz VCXOs. The
on-chip Voltage Controlled Crystal Oscillator accepts a
0 to 3.3 V input voltage to vary the output clocks by
±100 ppm. Using ICS’ patented VCXO and
analog/digital Phase-Locked Loop (PLL) techniques,
the device uses an inexpensive external 13.5 MHz
pullable crystal input to produce a 54 MHz output clock.
The MK3754D exhibits a moderate VCXO gain of
120 ppm/V typical, when used with a high quality
external pullable quartz crystal. The MK3754B offers a
higher VCXO gain of 150 ppm/V. The higher intrinsic
VCXO gain of the MK3754B may help compensate for
the reduced pullability of a low quality crystal used in
some applications. However, higher VCXO gain may
also increase clock output phase noise.
The frequency of the on-chip VCXO is adjusted by an
external control voltage input into pin VIN. Because
VIN is a high impedance input, it can be driven directly
from an PWM RC integrator circuit. Frequency output
increases with VIN voltage input. The usable range of
VIN is 0 to 3 V.
Features
MK3754D and MK3754B are drop-in upgrades to the
earlier MK3754S device
Packaged in 8-pin SOIC
Available in Pb (lead) free package
Operating voltage of 3.3 V
Uses an inexpensive 13.500 MHz external crystal
On-chip VCXO (patented) with pull range of 200 ppm
(minimum)
VCXO turning voltage of 0 to 3.3V
12 mA output drive capability at TTL levels
Advanced, low power, sub-micron CMOS process
MK3754D is Recommended for New Designs.
Block Diagram
54 M H z
X1
X2
Vo ltage
Con trolled
C rystal
O scillator
VIN
13.5 M H z
Pullable
C rystal
PL L/Clo ck
Syn thesis
Circu itry
VD D
GND