Clock-management devices target multiple frequencies
By Robert Cravotta -- EDN, December 25, 2003
To address the increasing frequencies for MIPS-processor-based embedded designs, PMC-Sierra offers the 1-GHz RM9000 family of clock-management devices. The clock-management devices include flexible clock generators and low-skew buffers. Flexible clock generators, such as the CM5371 GEN-M7K and CM5391L GEN-M9K, allow selection of multiple clock frequencies with less space, cost, and power and include spread-spectrum technology to reduce EMI (electromagnetic interference). The CM74CB218 LSB-2x9 low-skew buffer provides buffering of outputs for applications that need more copies of signals than the flexible clock generators support.
The CM74CB218 dual 1-to-8 low-skew buffer device can distribute a clock source at operation as fast as 200 MHz with less than a ±250-psec output-to-output skew. The CM5371 flexible clock generator supports RM5K and RM7K MIPS processors with four LVTTL (low-voltage-transistor-to-transistor-logic) clock interfaces. The CM5391L flexible clock generator supports RM9K MIPS processors with one LVDS (low-voltage-differential-signaling) and two LVTTL clock interfaces. The CM5371 and CM5391L accept 10-, 14.318-, 16-, and 25-MHz input frequencies and can provide 50-, 66.67-, 83.33-, 100-, 125-, 133.33-, 166.67-, or 200-MHz output frequencies. The devices are available for sampling now in 28-pin SSOP or 20-pin TSSOP packages and sell for $3.45 to $7.50 (10,000). All of the devices are available in lead-free packaging.
PMC Sierra, www.pmc-sierra.com.
