AD9557 Datasheet

• Supports GR-1244 Stratum 3 stability in holdover mode
• Supports smooth reference switchover with virtually no disturbance on output phase
• Supports Telcordia GR-253 jitter generation, transfer, and tolerance for SONET/SDH up to OC-192 systems
• Supports ITU-T G.8262 synchronous Ethernet slave clocks
• Supports ITU-T G.823, G.824, G.825, and G.8261
• Auto/manual holdover and reference switchover
• 2 reference inputs (single-ended or differential)
• Input reference frequencies: 2 kHz to 1250 MHz
• Reference validation and frequency monitoring (1 ppm)
• Programmable input reference switchover priority
• 20-bit programmable input reference divider
• 2 pairs of clock output pins, with each pair configurable as a single differential LVDS/HSTL output or as 2 single-ended CMOS outputs
• Output frequencies: 360 kHz to 1250 MHz
• Programmable 17-bit integer and 23-bit fractional feedback divider in digital PLL
• Programmable digital loop filter covering loop bandwidths from 0.1 Hz to 5 kHz (2 kHz maximum for <0.1 dB of peaking)
• Low noise system clock multiplier
• Frame sync support
• Adaptive clocking
• Optional crystal resonator for system clock input
• On-chip EEPROM to store multiple power-up profiles
• Pin program function for easy frequency translation configuration
• Software controlled power-down
• 40-lead, 6 mm × 6 mm, LFCSP package

• Network synchronization, including synchronous Ethernet and SDH to OTN mapping/demapping
• Cleanup of reference clock jitter
• SONET/SDH/OTN clocks up to 100 Gbps, including FEC
• Stratum 3 holdover, jitter cleanup, and phase transient control
• Wireless base station controllers
• Cable infrastructure
• Data communications

The AD9557 is a low loop bandwidth clock multiplier that provides jitter cleanup and synchronization for many systems, including synchronous optical networks (OTN/SONET/SDH). The AD9557 generates an output clock synchronized to up to four external input references. The digital PLL allows for reduction of input time jitter or phase noise associated with the external references. The digitally controlled loop and holdover circuitry of the AD9557 continuously generates a low jitter output clock even when all reference inputs have failed.

The AD9557 operates over an industrial temperature range of −40°C to +85°C. If more inputs/outputs are needed, refer to the AD9558 for the four-input/six-output version of the same device.