MK3235
Handheld System Clock Synthesizer
MDS 3235 D
1
Revision 092397
Printed 11/16/00
Integrated Circuit Systems, Inc.525
Race StreetSan JoseCA95126(408)295-9800telwww.icst.com
I C R O
C
LOC K
Input crystal frequency of 32.768 kHz
Lowest power solution available
Lowest profile clock solution where height is critical
Three output clocks
3.3V or 5.0V operation
Duty cycle of 45/55
14.3MHz or 14.3MHz+Comm clock power downs
Separate battery supply pin for 32 kHz runs to 2V
IDD less than 4A when 32 kHz running
Packaged in 16 pin narrow SOIC
The MK3235 is the smallest size, lowest power system
clock synthesizer available. It is the ideal way to
generate clocks for handheld computers, such as PDAs,
PICs, and other devices where low power is required.
Using analog Phase-Locked Loop (PLL) techniques,
the device operates from a single 32.768 kHz crystal to
produce the 32.768kHz, 14.318MHz, and serial
communications output clocks.
The device has three power down modes for the
14.3MHz, communications, and 32.768kHz clocks.
The MK3235 can save board space and cost even if it
only replaces the 32kHz oscillator circuitry and one
additional surface mount crystal or oscillator. The
extremely low IDD, the ease of surface mounting, and
the power down capability are added benefits in using
the part.
Description
Features
Crystal
Oscillator
VDD
GND
14.318MHz
Clock Synthesis
and Control
Circuitry
14.3 MHz
32.768 kHz
1.843 or
3.686 MHz
Output
Buffer
Output
Buffer
Output
Buffer
32.768 kHz
crystal
Block Diagram
VDD32
PDCOMM
PD14
PD
X1
X2
Communications
Clock Synthesis
and Control
Circuitry
MK3235
Handheld System Clock Synthesizer
MDS 3235 D
2
Revision 092397
Printed 11/16/00
Integrated Circuit Systems, Inc.525
Race StreetSan JoseCA95126(408)295-9800telwww.icst.com
I C R O
C
LOC K
Pin Assignment
Number
Name
Type
Description
1
X2
O
Crystal connection. Connect to 32.768 kHz crystal.
2
X1
I
Crystal connection. Connect to 32.768 kHz crystal.
3
VDD32
P
Separate power supply connection for 32.768kHz clock. Will operate to 2.0V.
4
VDD
P
Connect to +3.3V or +5V. Must be the same voltage as pin 14.
5
GND
P
Connect to ground.
6
COMMCLK
O
Serial communications (1.84 on -01 version, or 3.68MHz on -02 version) clock output.
7
32K
O
32.768 kHz square wave clock output.
8
PDCOMM
I
Power Down serial Communications and 14.3M clock outputs (stop low) when low.
9
GND
P
Connect to ground.
10
PD
I
Powers Down everything but 32kHz oscillator internally. 32kHz output buffer is off.
11
14.3M
O
14.318 MHz output clock.
12
GND
P
Connect to ground.
13
PD14
I
Power Down 14.318MHz clock output (stops low) when low.
14
VDD
P
Connect to +3.3V or +5V. Must be the same voltage as pin 4.
15
GND
P
Connect to ground.
16
GND
P
Connect to ground.
Pin Descriptions
Type: I = Input, O = output, P = power supply connection
Power Down status: Output clocks will stop in a low state when powered down
1
8
9
16
2
3
4
5
6
7
10
11
12
13
14
15
GND
PDCOMM
PD14
14.3M
PD
GND
VDD
GND
GND
32K
X2
GND
COMMCLK
VDD32
VDD
X1
External Components
The MK3235 requires a minimum number of external components for proper operation. Decoupling
capacitors of 0.1F should be connected between VDD and GND, and VDD32 and GND, as close to the
MK3235 as possible. A series resistor should be used on the VDD32 supply. A series termination resistor of
33
may be used for each clock output, except the 32.768 kHz. For tuning the real time clock output, use
a 32.768 kHz crystal with a load capacitance of 12.5pF, and connect a 20pF5% (NPO dielectric)
capacitor between each crystal pin and ground. The 32.768 kHz crystal must be connected as close to the
chip as possible. Consult MicroClock for a recommended external circuit schematic.
MK3235
Handheld System Clock Synthesizer
MDS 3235 D
3
Revision 092397
Printed 11/16/00
Integrated Circuit Systems, Inc.525
Race StreetSan JoseCA95126(408)295-9800telwww.icst.com
I C R O
C
LOC K
Note 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.
Note 2: When PD=0 (low) and VDD32 is greater than 2.0V, then the 32kHz oscillator will continue to run on the chip, but the
output is turned off. This allows for a quick power-up (<20ms), while the chip is only consuming approximately 1A.
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 30 seconds
260
C
Storage Temperature
-65
150
C
DC CHARACTERISTICS (at 5.0V unless otherwise noted)
DC CHARACTERISTICS (at 5.0V unless otherwise noted)
Operating Voltage, VDD
3.0
5.5
V
Operating Voltage,VDD32
2.0
5.5
V
Input High Voltage, VIH
VDD=5V
2.0
V
Input Low Voltage, VIL
VDD=5V
0.8
V
Output High Voltage, VOH, 3.3V or 5V
IOH=-4mA
VDD-0.4
V
Output High Voltage, VOH
VDD=5V, IOH=-25mA
2.4
V
Output Low Voltage, VOL
VDD=5V, IOL=25mA
0.4
V
Input High Voltage, VIH
VDD=3.3V
1.9
V
Input Low Voltage, VIL
VDD=3.3V
0.4
V
Output High Voltage, VOH
VDD=3.3V, IOH=-8mA
2.4
V
Output Low Voltage, VOL
VDD=3.3V, IOL=8mA
0.4
V
IDD Operating Supply Current, 5V
No Load
9
mA
IDD32 with only 32 kHz running, 5V
No Load
3.5
A
IDD Operating Supply Current, 3.3V
No Load
6
mA
IDD32 with only 32 kHz output running, 3.3V
No Load
2.5
A
IDD32, only 32 kHz osc. running, 3.3V, note 2
32kHz output off. PD=0
1
A
Short Circuit Current, 5V
32kHz output
30
mA
Short Circuit Current, 5V
14, 1.8MHz outputs
80
mA
Input Capacitance
7
pF
AC CHARACTERISTICS (at 5.0V unless otherwise noted)
AC CHARACTERISTICS (at 5.0V unless otherwise noted)
Input Frequency
32.768
kHz
Output Clock Rise and Fall Time, 0.2 to 0.8VDD
2
ns
Output Clock Duty Cycle, all MHz clocks
At VDD/2
45
49 to 51
55
%
32.768 kHz Clock Duty Cycle
At VDD32/2
57
%
Absolute Clock Period Jitter
14.318 MHz
-500
500
ps
Power up time, to all clocks stable, 32k running
VDD=3.3 or 5V
9
ms
Power on time,VDD32=0V to all clocks stable
32.768kHz crystal with ESR
25k
32.768kHz crystal with ESR
25k
500
1000
ms
Power on time, all power down pins taken high
32.768kHz oscillator running
32.768kHz oscillator running
15
ms
Electrical Specifications
MK3235
Handheld System Clock Synthesizer
MDS 3235 D
4
Revision 092397
Printed 11/16/00
Integrated Circuit Systems, Inc.525
Race StreetSan JoseCA95126(408)295-9800telwww.icst.com
I C R O
C
LOC K
b
D
E
H
e
Q
c
A
h x 45
Package Outline and Package Dimensions
Ordering Information
16 pin SOIC narrow
Inches
Inches
Millimeters
Millimeters
Symbol
Min
Max
Min
Max
A
0.055
0.068
1.397
1.7272
b
0.013
0.019
0.330
0.483
c
0.007
0.010
0.191
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
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.
Part/Order Number
Marking
Communications Clock
Package
Temperature
MK3235-01S
MK3235-01S
1.843 MHz
16 pin SOIC
0-70C
MK3235-02S
MK3235-02S
3.686 MHz
16 pin SOIC
0-70C
MK3235-01STR
MK3235-01S
1.843 MHz
Add Tape & Reel
0-70C
MK3235-02STR
MK3235-02S
3.686 MHz
Add Tape & Reel
0-70C
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