MK2731-02A
Low Cost VCXO
MDS2731-02AD 1Revision 12037 Printed 12/3/97
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
ICROCLOCK
Block Diagram
Description Features
The MK2731-02 is a low cost, low jitter, high
performance VCXO and PLL clock synthesizer
designed to replace expensive discrete VCXOs.
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 MicroClock’s
proprietary VCXO and analog Phase-Locked
Loop (PLL) techniques (patents pending), the
device uses an inexpensive 12.288 MHz or
13.5 MHz pullable crystal input to produce up to
three output clocks.
MicroClock manufactures the largest variety of
Set-Top Box and multimedia clock synthesizers
for all applications. Consult MicroClock to
eliminate VCXOs, crystals and oscillators from
your board.
• Packaged in 16 pin narrow SOIC
• Uses an inexpensive 12.288 or 13.50 MHz crystal
• On-chip VCXO (patent pending) with pull range
of 200ppm (minimum)
• VCXO tuning voltage of 0 to 3V
• Zero ppm synthesis error in all clocks
• 25mA output drive capability at TTL levels
• Advanced, low power, sub-micron CMOS process
• 5V operating voltage
Voltage
Controlled
Crystal
Oscillator
PLL/Clock
Synthesis
Circuitry
12.288 MHz or
13.5 MHz
pullable
crystal
X1
X2
VIN Output
Buffer
Output
Buffer
OE (all outputs)
CLK2
CLK3
S2:0 3Output
Buffer CLK1
MK2731-02A
Low Cost VCXO
MDS2731-02AD 2Revision 12037 Printed 12/3/97
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
ICROCLOCK
Pin Descriptions
Key: I = Input, O = output, P = power supply connection, VI = analog voltage input
Pin Assignment
Number Name Type Description
1X2 XO Crystal connection. Connect to a pullable 12.288 or 13.5 MHz crystal.
2X1 XI Crystal connection. Connect to a pullable 12.288 or 13.5 MHz crystal.
3VDD P VDD. Connect to +5V.
4VIN VI Voltage Input to VCXO. Zero to 3V signal which controls the frequency of the VCXO.
5GND P Connect to ground.
6 GND P Connect to ground.
7 OE I Output Enable. Active high. Tri-states all outputs when low.
8CLK1 O Clock output 1 determined by status of S2, S1, S0. See table above.
9S0 I Clock Select 0. Selects outputs per table above.
10 S1 I Clock Select 1. Selects outputs per table above.
11 CLK2 O Clock output 2 determined by status of S2, S1, S0. See table above.
12 NC - No Connect. Nothing is connected internally to this pin.
13 CLK3 O Clock output 3 determined by status of S2, S1, S0. See table above.
14 S2 I Clock Select 2. Selects outputs per table above.
15 NC - No Connect. Nothing is connected internally to this pin.
16 VDD P Connect to +5V.
Output Clock Select Table (MHz)
16
15
14
13
16 pin narrow (150 mil) SOIC
12
11
10
9
1
2
3
4
5
6
7
8
MK2731-02
VDD
GND
X2
X1
VIN
CLK1
GND
OE S1
S0
CLK2
NC
VDD
S2
Input S2 S1 S0 CLK1 CLK2 CLK3
12.288 0 0 0 Off 98.304 Off
12.288 0 0 1 28.672 Off Off
12.288 0 1 0 3.584 Off Off
13.5 0 1 1 19.5 117 Off
13.5 1 0 0 19.44 Off Off
13.5 1 0 1 27 54 27
13.5 1 1 0 27 27 27
13.5 1 1 1 27 27 Off
CLK3
NC
MK2731-02A
Low Cost VCXO
MDS2731-02AD 3Revision 12037 Printed 12/3/97
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
ICROCLOCK
Parameter Conditions Minimum Typical Maximum Units
ABSOLUTE MAXIMUM RATINGS (note 1)
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)
DC CHARACTERISTICS (VDD = 5.0V unless noted)
Operating Voltage, VDD 4.75 5.25 V
Input High Voltage, VIH, X1 pin only 3.5 2.5 V
Input Low Voltage, VIL, X1 pin only 2.5 1.5 V
Input High Voltage, VIH 2 V
Input Low Voltage, VIL 0.8 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, note 2 24 mA
Short Circuit Current Each output ±100 mA
Input Capacitance S2, S1, S0, OE 7 pF
Frequency synthesis error All clocks 0 ppm
VIN, VCXO control voltage 0 3 V
AC CHARACTERISTICS (VDD = 5.0V unless noted)
AC CHARACTERISTICS (VDD = 5.0V unless noted)
Input Crystal Frequency 12.288 or 13.5 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 60 %
Maximum Absolute Jitter, short term 200 ps
27 MHz output pullability, note 3 0V ≤ VIN ≤ 3V ±100 ppm
Electrical Specifications
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 CLK1, CLK3 = 27MHz, and CLK2 = 54MHz.
3. With a MicroClock approved pullable crystal.
External Components
The MK2731-02 requires a minimum number of external components for proper operation. Decoupling
capacitors of 0.1µF should be connected between VDD and GND on pins 3 and 5, as close to the
MK2731-02 as possible. A series termination resistor of 33Ω may be used for each 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, with 14pF load capacitance. Consult MicroClock for recommended suppliers.
IMPORTANT - consult the application note MAN05 for layout guidelines.
MK2731-02A
Low Cost VCXO
MDS2731-02AD 4Revision 12037 Printed 12/3/97
MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax
ICROCLOCK
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.
Package Outline and Package Dimensions
Ordering Information
Part/Order Number Marking Shipping packaging Package Temperature
MK2731-02S MK2731-02S tubes 16 pin SOIC 0-70°C
MK2731-02STR MK2731-02S tape and reel 16 pin SOIC 0-70°C
b
D
E H
e
Qc
h x 45°
A
16 pin SOIC narrow
Inches
Inches
Millimeters
Millimeters
Symbol Min Max Min Max
A0.055 0.070 1.397 1.778
b 0.013 0.019 0.330 0.483
c 0.007 0.010 0.190 0.254
D 0.385 0.400 9.779 10.160
E 0.150 0.160 3.810 4.064
H 0.225 0.245 5.715 6.223
e
.050 BSC
.050 BSC
1.27 BSC
1.27 BSC
h 0.016 0.406
Q 0.004 0.01 0.102 0.254
