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I C R O C LOC K
Description
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.
MK3235 Handheld System Clock Synthesizer
Features
* 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
Block Diagram
VDD GND
PD14
14.318MHz Clock Synthesis and Control Circuitry
Output Buffer
14.3 MHz
PDCOMM PD VDD32 32.768 kHz crystal X1 Crystal Oscillator
X2
Communications Clock Synthesis and Control Circuitry
Output Buffer
1.843 or 3.686 MHz
Output Buffer
32.768 kHz
MDS 3235 D
1 Revision 092397 Printed 11/16/00 Integrated Circuit Systems, Inc.*525 Race Street*San Jose*CA*95126*(408)295-9800tel*www.icst.com
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Pin Assignment
X2 X1 VDD32 VDD GND COMMCLK 32K PDCOMM 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 GND GND VDD PD14 GND 14.3M PD GND
MK3235 Handheld System Clock Synthesizer
Pin Descriptions
Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Name X2 X1 VDD32 VDD GND COMMCLK 32K PDCOMM GND PD 14.3M GND PD14 VDD GND GND Type O I P P P O O I P I O P I P P P Description Crystal connection. Connect to 32.768 kHz crystal. Crystal connection. Connect to 32.768 kHz crystal. Separate power supply connection for 32.768kHz clock. Will operate to 2.0V. Connect to +3.3V or +5V. Must be the same voltage as pin 14. Connect to ground. Serial communications (1.84 on -01 version, or 3.68MHz on -02 version) clock output. 32.768 kHz square wave clock output. Power Down serial Communications and 14.3M clock outputs (stop low) when low. Connect to ground. Powers Down everything but 32kHz oscillator internally. 32kHz output buffer is off. 14.318 MHz output clock. Connect to ground. Power Down 14.318MHz clock output (stops low) when low. Connect to +3.3V or +5V. Must be the same voltage as pin 4. Connect to ground. Connect to ground.
Type: I = Input, O = output, P = power supply connection Power Down status: Output clocks will stop in a low state when powered down
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.
MDS 3235 D
2 Revision 092397 Printed 11/16/00 Integrated Circuit Systems, Inc.*525 Race Street*San Jose*CA*95126*(408)295-9800tel*www.icst.com
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Electrical Specifications
Parameter Supply Voltage, VDD Inputs and Clock Outputs Ambient Operating Temperature Soldering Temperature Storage Temperature Operating Voltage, VDD Operating Voltage,VDD32 Input High Voltage, VIH Input Low Voltage, VIL Output High Voltage, VOH, 3.3V or 5V Output High Voltage, VOH Output Low Voltage, VOL Input High Voltage, VIH Input Low Voltage, VIL Output High Voltage, VOH Output Low Voltage, VOL IDD Operating Supply Current, 5V IDD32 with only 32 kHz running, 5V IDD Operating Supply Current, 3.3V IDD32 with only 32 kHz output running, 3.3V IDD32, only 32 kHz osc. running, 3.3V, note 2 Short Circuit Current, 5V Short Circuit Current, 5V Input Capacitance Input Frequency Output Clock Rise and Fall Time, 0.2 to 0.8VDD Output Clock Duty Cycle, all MHz clocks 32.768 kHz Clock Duty Cycle Absolute Clock Period Jitter Power up time, to all clocks stable, 32k running Power on time,VDD32=0V to all clocks stable Power on time, all power down pins taken high
MK3235 Handheld System Clock Synthesizer
Minimum Typical Maximum 7 VDD+0.5 70 260 150 5.5 5.5 0.8 VDD-0.4 2.4 0.4 1.9 0.4 2.4 0.4 9 3.5 6 2.5 1 30 80 7 32.768 Units V V C C C V V V V V V V V V V V mA A mA A A mA mA pF kHz ns % % ps ms ms ms
Conditions Referenced to GND Referenced to GND Max of 30 seconds
ABSOLUTE MAXIMUM RATINGS (note 1)
-0.5 0 -65 3.0 2.0 2.0
DC CHARACTERISTICS (at 5.0V unless otherwise noted)
VDD=5V VDD=5V IOH=-4mA VDD=5V, IOH=-25mA VDD=5V, IOL=25mA VDD=3.3V VDD=3.3V VDD=3.3V, IOH=-8mA VDD=3.3V, IOL=8mA No Load No Load No Load No Load 32kHz output off. PD=0 32kHz output 14, 1.8MHz outputs
AC CHARACTERISTICS (at 5.0V unless otherwise noted)
2 55 500 9 500 15 1000
At VDD/2 45 At VDD32/2 14.318 MHz -500 VDD=3.3 or 5V 32.768kHz crystal with ESR 25k 32.768kHz oscillator running
49 to 51 57
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.
MDS 3235 D
3 Revision 092397 Printed 11/16/00 Integrated Circuit Systems, Inc.*525 Race Street*San Jose*CA*95126*(408)295-9800tel*www.icst.com
I C R O C LOC K
Package Outline and Package Dimensions
MK3235 Handheld System Clock Synthesizer
16 pin SOIC narrow
Symbol A b c D E H e h Q Inches Min Max 0.055 0.068 0.013 0.019 0.007 0.010 0.385 0.400 0.150 0.160 0.225 0.245 .050 BSC 0.016 0.004 0.01 Millimeters Min Max 1.397 1.7272 0.330 0.483 0.191 0.254 9.779 10.160 3.810 4.064 5.715 6.223 1.27 BSC 0.406 0.102 0.254
E
H
D Q e c
h x 45 A
b
Ordering Information
Part/Order Number MK3235-01S MK3235-02S MK3235-01STR MK3235-02STR Marking MK3235-01S MK3235-02S MK3235-01S MK3235-02S Communications Clock 1.843 MHz 3.686 MHz 1.843 MHz 3.686 MHz Package 16 pin SOIC 16 pin SOIC Add Tape & Reel Add Tape & Reel Temperature 0-70C 0-70C 0-70C 0-70C
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 3235 D
4 Revision 092397 Printed 11/16/00 Integrated Circuit Systems, Inc.*525 Race Street*San Jose*CA*95126*(408)295-9800tel*www.icst.com

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