MK2727

Low Cost 27 MHz VCXO

Description Features

The MK2727 is MicroClock’s lowest cost, low • Packaged in 8 pin narrow SOIC
jitter, high performance VCXO and PLL clock • Uses an inexpensive 13.500 MHz external crystal
synthesizer designed to replace expensive 27MHz
VCXOs. The on-chip Voltage Controlled Crystal • On-chip VCXO (patented) with pull range of
Oscillator accepts a 0 to 3V input voltage to cause 200ppm (minimum)
the output clocks to vary by ±100 ppm. Using
• VCXO tuning voltage of 0 to 3V
MicroClock’s patented VCXO and analog Phase-
Locked Loop (PLL) techniques, the device uses an • 25mA output drive capability at TTL levels
inexpensive external 13.5 MHz pullable crystal • Advanced, low power, sub-micron CMOS process
input to produce a
27 MHz output clock. • 5V operating voltage

MicroClock manufactures the largest variety of

Set-Top Box and multimedia clock synthesizers
for all applications. If more clock outputs are
needed, see the MK2731 or MK277x family of
parts. Consult MicroClock to eliminate VCXOs,
crystals and oscillators from your board.

Block Diagram

VIN

X1
Voltage PLL/Clock
13.5 MHz Output
Controlled Synthesis 27MHz
pullable Buffer
Crystal Circuitry
crystal
X2 Oscillator

MDS 2727 B 1 Revision 111600 Printed 11/16/00

Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
 MK2727
Low Cost 27 MHz VCXO

Pin Assignment

MK2727
X1 1 8 X2

VDD 2 7 GND
VIN 3 6 VDD
GND 4 5 CLK

8 pin (150 mil) SOIC

Pin Descriptions
Number Name Description
1 X1 Crystal connection. Connect to a pullable 13.5 MHz crystal.
2 VDD VDD. Connect to +5V.
3 VIN Voltage input to VCXO. Zero to 3V analog input which controls the frequency of the VCXO.
4 GND Connect to ground.
5 CLK 27 MHz clock output.
6 VDD VDD. Connect to +5V.
7 GND Connect to ground.
8 X2 Crystal connection. Connect to a pullable 13.5 MHz crystal.

MDS 2727 B 2 Revision 111600 Printed 11/16/00

Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
 MK2727
Low Cost 27 MHz VCXO

Electrical Specifications
Parameter Conditions Minimum Typical Maximum Units
ABSOLUTE MAXIMUM RATINGS (note 1)
Supply voltage, VDD Referenced to GND 7 V
Inputs and Clock Outputs Referenced to GND -0.5 VDD+0.5 V
Ambient Operating Temperature 0 70 °C
Soldering Temperature Max of 10 seconds 260 °C
Storage temperature -65 150 °C
DC CHARACTERISTICS (VDD = 5.0V unless noted)
Operating Voltage, VDD 4.75 5.25 V
Output High Voltage, VOH IOH=-25mA 2.4 V
Output Low Voltage, VOL IOL=25mA 0.4 V
Output High Voltage, VOH, CMOS level IOH=-8mA VDD-0.4 V
Operating Supply Current, IDD No Load 20 mA
Short Circuit Current ±100 mA
VIN, VCXO control voltage 0 3 V
AC CHARACTERISTICS (VDD = 5.0V unless noted)
Input Crystal Frequency 13.50000 MHz
Input Crystal Accuracy ±30 ppm
Output Clock Rise Time 0.8 to 2.0V 1.5 ns
Output Clock Fall Time 2.0 to 0.8V 1.5 ns
Output Clock Duty Cycle At 1.4V 40 50 60 %
Maximum Absolute Jitter, short term 200 ps
27 MHz output pullability, note 2 0V ≤ VIN ≤ 3V ±100 ppm

Notes: 1. Stresses beyond those listed under Absolute Maximum Ratings could cause permanent damage to the device. Prolonged
exposure to levels above the operating limits but below the Absolute Maximums may affect device reliability.
2. With a MicroClock approved pullable crystal.

External Components
The MK2727 requires a minimum number of external components for proper operation. A decoupling
capacitor of 0.1µF should be connected between VDD and GND on pins 2 and 4, as close to the MK2727
as possible. A series termination resistor of 33Ω may be used for the clock output. The input crystal must be
connected as close to the chip as possible. The input crystal should be a parallel mode, pullable, AT cut,
13.5MHz, with 14pF load capacitance. Consult MicroClock for recommended suppliers. IMPORTANT -
read application note MAN05 before laying out the PCB.

MDS 2727 B 3 Revision 111600 Printed 11/16/00

Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com
 MK2727
Low Cost 27 MHz VCXO
Package Outline and Package Dimensions

8 pin SOIC

Inches Millimeters
Symbol Min Max Min Max
E H A 0.055 0.068 1.397 1.7272
b 0.013 0.019 0.330 0.483
Pin 1 D 0.185 0.200 4.699 5.080
E 0.150 0.160 3.810 4.064
H 0.225 0.245 5.715 6.223
e .050 BSC 1.27 BSC
h x 45° h 0.015 0.381
D Q 0.004 0.01 0.102 0.254

Q A
c
e b

Ordering Information

Part/Order Number Marking Shipping packaging Package Temperature

MK2727S MK2727S tubes 8 pin SOIC 0-70°C
MK2727STR MK2727S tape and reel 8 pin SOIC 0-70°C

CHANGE HISTORY
Version Date first published Status Comments
A 12/12/96 Advance Original
B 12/2/97 Released Updated logo & address. Corrected pkg height.

While the information presented herein has been checked for both accuracy and reliability, MicroClock Incorporated assumes no responsibility for either its use or for the
infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in
normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements
are not recommended without additional processing by MicroClock. MicroClock reserves the right to change any circuitry or specifications without notice. MicroClock does not
authorize or warrant any MicroClock product for use in life support devices or critical medical instruments.

MDS 2727 B 4 Revision 111600 Printed 11/16/00

Integrated Circuit Systems, Inc.•525 Race Street•San Jose•CA•95126•(408)295-9800tel•www.icst.com