Postage-Stamp Size Timing Module Prepares To Run On Line Cards

Measuring just 1" x 1", the ZL30462 claims to be the industry's most compact timing module for high-speed line cards. Packing both digital and analog PLL technology and a 20 MHz master oscillator, the compact, tiny module is suitable for line cards in SDH/SONET edge equipment, such as media gateways, uplink systems, and edge switches, as well as in master timing cards for SDH access equipment. Clocking frequencies include jitter-attenuated 155.52-MHz LVPECL and 19.44-MHz CMOS, two 8-kHz frame pulses, and clocks operating at 2.048, 8.192 and 16.384 MHz. The module accepts frequency references from two independent sources, and each input is programmable for operation at 8 kHz and 1.544, 2.048 or 19.44 MHz. Reliability features include time-interval error correction and automatic holdover. Should the primary input reference become unstable, the holdover circuitry maintains network synchronization while the module automatically switches to the secondary reference. The ZL30462 in a surface-mount, 40-pin DIL costs $101.05 each/100. ZARLINK SEMICONDUCTOR, Ottawa, Canada. (613) 270-7115.