The MK1442/3 are the ideal way to generate clocks for desktop computer motherboards and LAN workstations. Using analog Phase-Locked Loop (PLL) techniques, the devices accept a 14.318 MHz crystal input to produce multiple output clocks up to 100 MHz. They provide 2XCPU, CPU, floppy controller, keyboard, system, SCSI and Ethernet clocks. The MK1442/3 are perfect for new Pentium™ Processor, PCI bus and 486 systems. The devices can operate at 5V or 3.3V up to and including 80MHz on the CPU clock. The devices are identical except the MK1442 has an Output Enable (OE) pin that tri-states all outputs when taken low, and the MK1443 has an extra 14.318 MHz clock.
The MK1442 and MK1443 are clock‑generator ICs designed for desktop computer motherboards and LAN workstations. They accept a 14.318 MHz crystal input and synthesize multiple output clocks (CPU, 2XCPU, SCSI, Ethernet, floppy, keyboard, etc.) up to 100 MHz. The MK1442 includes an Output Enable pin that can tri‑state all outputs, while the MK1443 adds a second 14.318 MHz clock output.
The devices are supplied in a 16‑pin narrow SOIC package, operate from either 5 V or 3.3 V, and feature low‑power CMOS construction. Electrical specifications include a supply voltage range of 3.0‑5.5 V, typical operating current of 35 mA at 80 MHz, and frequency accuracy of ±1 ppm when proper crystals and capacitors are used.
| Supply voltage (VDD) | 3.0 V – 5.5 V |
|---|---|
| Maximum output clock frequency | 100 MHz |
| Output drive capability | 25 mA at TTL levels |
| Operating temperature range | 0 °C – 70 °C |
| Skew of 2XCPU to CPU | ±250 ps |
The device operates from a supply voltage between 3.0 V and 5.5 V.
It can provide seven or eight output clocks, including CPU, 2XCPU, SCSI, Ethernet, floppy, and keyboard clocks.
The typical supply current at 80 MHz with no load is 35 mA.