Compact OCXOs Called Most Stable SMT Frequency Source

The first true SMT oscillators capable of bettering the Stratum IIIE holdover stability requirement are said to be the CFPO-11 series oven-controlled crystal oscillators (OCXOs). The devices are intended for use as a reference frequency source in GSM and other cellular base stations, as well as in fixed-line SDH/SONET switching systems.Measuring just 25 mm x 22 mm x 14 mm and weighing less than 10 g, the devices offer stability to within ±5 parts per billion (ppb) over a temperature range of -10°C to 70°C. Stabilities down to ±2 ppb are available on special order.The best performers in the series, designated CFPO-11 H, offer output frequencies from 8.192 MHz to 13 MHz. Stability with respect to load and supply voltage variations is around ±1 ppb with aging/day down to ±0.07 ppb. The devices' compact oven reaches steady state within 5 minutes.