ACS8522T

Overview

The ACS8522T is a Synchronous Equipment Timing Source (SETS) IC designed for SONET/SDH network elements. It generates SEC and synchronization clocks using Digital Phase Locked Loops (DPLLs). The device accepts four independent TTL input reference clocks and produces four output clocks, including one differential PECL/LVDS port and three TTL ports. Operating on a single 3.3 V supply with 5 V tolerant inputs, it supports Stratum 3, 4E, 4, and SMC applications. Key electrical parameters include a 12.8 MHz reference clock input, an operating voltage range of 3.0 V to 3.6 V, and a commercial temperature range of -40 °C to +85 °C.

Feature Summary

• Generates independent T0 and T4 paths for node timing and equipment synchronization
• Accepts up to four independent input SEC reference sources with quality monitoring
• Supports Free-run, Locked, and Holdover modes with automatic or forced switching
• Includes SPI-compatible serial interface and IEEE 1149.1 JTAG boundary scan support

Applications

• SONET/SDH Network Element timing
• Stratum 3, 4E, and 4 synchronization systems
• SONET Minimum Clock (SMC) applications

Procurement Notes

Verify the ordering suffix 'T' indicates the lead-free, RoHS, and WEEE compliant version of the ACS8522. Confirm package type is LQFP 64-pin. Ensure external oscillator selection (TCXO or OCXO) matches required Stratum performance specifications.

Selection Notes

Select based on required Stratum level and holdover stability needs. The device allows choice between TCXO or OCXO to define performance. Verify input frequency compatibility (2 kHz to 100 MHz) and output requirements (PECL/LVDS vs TTL). Check if T0 path advanced features like hit-less switching are necessary versus the simpler T4 path.

Part Context

The ACS8522T is part of the Semtech ACS8522 SETS LITE family. It serves as a single-chip solution for synchronous equipment timing in telecommunications infrastructure, replacing traditional analog PLL solutions with digital synthesis for consistent performance across temperature and voltage variations.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.