I C R O C LOC K MK3234 Portable System Clock Synthesizer Description Features The MK3234 is the smallest size, lowest power system clock synthesizer available. It is the ideal way to generate clocks for portable computers 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, CPU, and ISA bus (system) output clocks. • Input crystal frequency of 32.768 kHz • Lowest power solution available • Lowest profile clock solution where height is critical • Output clock frequencies up to 50 MHz • Three output clocks • 3.3V or 5.0V operation • Duty cycle of 45/55 • Eight selectable CPU frequencies • CPU clock power down • Separate battery supply pin for 32 kHz runs to 2V • IDD less than 4µA when 32 kHz running • Packaged in 16 pin narrow (0.150”) SOIC The device has an individual power down pin for the CPU clock, and a power down pin for the entire device. The MK3234 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, the upgradeability of CPU frequencies, and the power down capability are added benefits in using the part. Block Diagram VDD GND CPUS0 CPUS1 CPUS2 PDCPU PD VDD32 CPU Clock Synthesis and Control Circuitry Output Buffer CPUCLK System Clock Synthesis and Control Circuitry Output Buffer 14.318 MHz Output Buffer 32.768 kHz 32.768 kHz crystal X1 Crystal Oscillator X2 1 Revision 022798 Printed 11/16/00 MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax MDS 3234 C I C R O C LOC K Pin Assignment CPU Clock Decoding CPUS2 1 X2 X1 2 3 VDD32 VDD GND 32K GND MK3234 Portable System Clock Synthesizer 16 15 CPUS1 14 CPUCLK 4 5 13 12 VDD GND 6 7 11 14.3M 10 8 9 PD PDCPU CPUS0 CPUS2 CPUS1 CPUS0 CPUCLK (MHz) 0 0 0 8.00 0 0 1 13.00 0 1 0 16.00 0 1 1 20.00 1 0 0 40.00 1 0 1 25.00 1 1 0 50.00 1 1 1 33.33 Frequency transitions will occur smoothly. Pin Descriptions Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Name CPUS2 X2 X1 VDD32 VDD GND 32K GND PDCPU PD 14.3M GND VDD CPUCLK CPUS0 CPUS1 Type I O I P P P O P I I O P P O I I Description Select 2 for CPUCLK frequencies. See Table above. 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 13. Connect to ground. 32.768 kHz square wave clock output. Connect to ground. Power Down CPU clock output (stops low) when low. Powers Down everything but 32kHz oscillator internally. 32kHz output buffer is off. 14.318 MHz clock output. Do not use to drive video CRT controller. Connect to ground. Connect to +3.3V or +5V. Must be the same voltage as pin 5. CPUCLK output. See Table above. Select 0 for CPUCLK frequencies. See Table above. Select 1 for CPUCLK frequencies. See Table above. 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 MK3234 requires a minimum number of external components for proper operation. Decoupling capacitors of 0.1µF should be connected between VDD and GND, and VDD32 and GND, as close to the MK3234 as possible. A series resistor of 10kΩ should be used on the VDD32 supply. A series termination resistor of 33Ω 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 20pF±5% (NPO dielectric) capacitor between each crystal pin and ground. The 32.768 kHz crystal must be connected as close to the chip as possible. The 14.3 MHz output is not suitable for driving CRT displays. A separate 14.318 MHz crystal should be used at the input to the graphics controller chip. Consult MicroClock for a recommended external circuit schematic. 2 Revision 022798 Printed 11/16/00 MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax MDS 3234 C I C R O C LOC K MK3234 Portable System Clock Synthesizer Electrical Specifications Parameter Conditions Minimum Typical Maximum Units 7 VDD+0.5 70 260 150 V V °C °C °C 5.5 5.5 V V V V V V V V V V mA µA mA µA µA mA mA pF ABSOLUTE MAXIMUM RATINGS (note 1) Supply Voltage, VDD Inputs and Clock Outputs Ambient Operating Temperature Soldering Temperature Storage Temperature Referenced to GND Referenced to GND -0.5 0 Max of 30 seconds -65 DC CHARACTERISTICS (at 5.0V unless otherwise noted) Operating Voltage, VDD Operating Voltage,VDD32 Input High Voltage, VIH Input Low Voltage, VIL 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 VDD=5V VDD=5V 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, 50MHz No Load No Load, 50MHz No Load 32kHz output off. PD=0 32 kHz output CPU output 3.0 2.0 2.0 0.8 2.4 0.4 1.9 0.4 2.4 0.4 15 3.5 9 2.5 1 ±30 ±100 7 AC CHARACTERISTICS (at 5.0V unless otherwise noted) 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, CPU clock Power up time, CPU off to 50 MHz, 32k running Transition time, 8 MHz to 50 MHz Transition time, 50 MHz to 8 MHz Power on time,VDD32=0V to all clocks stable Power on time, all power down pins taken high 32.768 At VDD/2 45 At VDD32/2 20 to 50 MHz -500 VDD=3.3 or 5V VDD=3.3 or 5V VDD=3.3 or 5V 32.768kHz crystal with ESR ≤25kΩ 32.768kHz oscillator running 49 to 51 57 2 55 500 9 4 2.5 500 15 1000 kHz ns % % ps ms ms ms ms ms 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 1µA. 3 Revision 022798 Printed 11/16/00 MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax MDS 3234 C I C R O C LOC K MK3234 Portable System Clock Synthesizer Package Outline and Package Dimensions E e Symbol A b c D E H e h Q H h x 45° D Q 16 pin SOIC narrow b 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 A c Ordering Information Part/Order Number Marking Package Temperature MK3234-01S MK3234-01STR MK3234-01S MK3234-01S 16 pin SOIC Add Tape & Reel 0-70°C 0-70°C 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. 4 Revision 022798 Printed 11/16/00 MicroClock Division of ICS•1271 Parkmoor Ave.•San Jose•CA•95126•(408)295-9800tel•(408)295-9818fax MDS 3234 C