Phase Locked Loop Devices
Semtech Corp. announces the ACS8946 and ACS8944 jitter attenuating and multiplying (JAM) phase locked loop (PLL) devices for generating low jitter output clocks for low-cost SONET/SDH and Gigabit Ethernet line cards. These devices are part of Semtech’s JAM PLL family, a sister family to the synchronous equipment timing source (SETS) product family. The ACS8946 and ACS8944 are designed for clock de-jitter applications in telecom line cards supporting speeds up to OC-12/STM-4. They deliver output jitter of 2.8 ps rms to packet framing or serializing devices — well below the Telcordia GR-253 standard of 16 ps rms for OC-12. Both JAM PLL devices offer frequency programmability to any SONET/SDH rate, including 19.44, 38.88, 77.76 and 155.52 MHz. The ACS8946 and ACS8944 also feature an integrated voltage-controlled oscillator (VCO) to reduce parts count and build cost.