MK3234-01STR

I C R O C LOC K Description 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. 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. MK3234 Portable System Clock Synthesizer Features 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 Block Diagram VDD GND CPUS0 CPUS1 CPUS2 PDCPU CPU Clock Synthesis and Control Circuitry Output Buffer CPUCLK PD VDD32 32.768 kHz crystal X1 Crystal Oscillator X2 System Clock Synthesis and Control Circu...