Description

The ZL38004GGG2 is a special purpose audio IC that is designed for carrier-grade network equipment. It is a highly integrated device that provides all the necessary functionality for a central timing card. This card includes features such as input reference monitoring, automatic input reference selection, support for external timing and line timing modes, hitless reference switching, wander and jitter filtering, master/slave crossover for minimizing phase alignment between redundant timing cards, and independent derived output timing path for support of the SETS functionality.

Specifications and features

- Supports the requirements of ITU-T G.8262 for synchronous Ethernet Equipment slave Clocks (EEC option 1 and 2)
- Supports the requirements of Telcordia GR-1244 Stratum 3 and GR-253, ITU-T G.813, and G.781 SETS
- Supports ITU-T G.823, G.824 and G.8261 for 2048 kbit/s and 1544 kbit/s interfaces
- Meets the SONET/SDH jitter generation requirements up to OC-48/STM-16
- Synchronizes to telecom reference clocks (2 kHz, N*8 kHz up to 77.76 MHz, 155.52 MHz) or to Ethernet reference clocks (25 MHz, 50 MHz, 62.5 MHz, 125 MHz)
- Supports composite clock inputs (64 kHz, 64 kHz + 8 kHz, 64kHz + 8 kHz + 400 Hz)
- Generates standard SONET/SDH clock rates (e.g., 19.44 MHz, 38.88 MHz, 77.76 MHz, 155.52 MHz, 622.08 MHz) or Ethernet clock rates (e.g., 25 MHz, 50 MHz, 125 MHz, 156.25 MHz, 312.5 MHz) for synchronizing Gigabit Ethernet PHYs
- Programmable output synthesizers (P0, P1) generate telecom clock frequencies from any multiple of 8 kHz up to 100 MHz
- Generates several styles of telecom frame pulses with selectable pulse width, polarity, and frequency
- Provides two DPLLs which are independently configurable through a serial interface
- Internal state machine automatically controls mode of operation (free-run, locked, holdover)
- Flexible input reference monitoring automatically disqualifies references based on frequency and phase irregularities
- Provides automatic reference switching and holdover during loss of reference input
- Supports master/slave configuration and dynamic input to output delay compensation for AdvancedTCA™
- Configurable input to output delay and output to output phase alignment

Application Scenarios

- ITU-T G.8262 System Timing Cards which support 1 GbE and 10 GbE interfaces
- Telcordia GR-253 Carrier Grade SONET/SDH Stratum 3 System Timing Cards
- System Timing Cards which supports ITU-T G.781 SETS (SDH Equipment Timing Source)

Comparison

- Highly integrated device with all necessary functionality for a central timing card
- Supports various industry standards and requirements
- Synchronizes to telecom and Ethernet reference clocks
- Configurable input and output options
- Flexible input reference monitoring
- Automatic reference switching and holdover functionality
- Supports master/slave configuration and dynamic input to output delay compensation

- Requires expertise in network equipment and timing cards to fully utilize its features
- May not be suitable for applications outside of carrier-grade network equipment