The 10 clock outputs of the AD9542 are synchronized to any one of up to four input references. The digital phase-locked loops (DPLLs) reduce timing jitter associated with the external references. The digitally controlled loop and holdover circuitry continuously generate a low jitter output signal, even when all reference inputs fail.
The AD9542 is available in a 48-lead LFCSP (7 mm × 7 mm) package and operates over the −40°C to +85°C temperature range.
Note that throughout this data sheet, multifunction pins, such as SDO/M5, are referred to either by the entire pin name or by a single function of the pin, for example, M5, when only that function is relevant.
Applications
SyncE jitter cleanup and synchronization
Optical transport networks (OTN), SDH, and macro and small cell base stations
OTN mapping/demapping with jitter cleaning
Small base station clocking, including baseband and radio
Stratum 2, Stratum 3e, and Stratum 3 holdover, jitter cleanup, and phase transient control
JESD204B support for analog-to-digital converter (ADC) and digital-to-analog converter (DAC) clocking
Cable infrastructures
Carrier Ethernet
### Features and Benefits
Dual DPLL synchronizes 2 kHz to 750 MHz physical layer clocks providing frequency translation with jitter cleaning of noisy references
Complies with ITU-T G.8262 and Telcordia GR-253
Supports Telcordia GR-1244, ITU-T G.812, G.813, G.823, G.824, and G.825
Continuous frequency monitoring and reference validation for frequency deviation as low as 50 ppb
Both DPLLs feature a 24-bit fractional divider with 24-bit programmable modulus
Programmable digital loop filter bandwidth: 10−4 Hz to 1850 Hz
Automatic and manual holdover and reference switchover, providing zero delay, hitless, or phase buildout operation
Programmable priority-based reference switching with manual, automatic revertive, and automatic nonrevertive modes supported
5 pairs of clock output pins with each pair useable as differential LVDS/HCSL/CML or as 2 single-ended outputs (1 Hz to 500 MHz)
2 differential or 4 single-ended input references
Crosspoint mux interconnects reference inputs to PLLs
Provides internal capability to combine the low phase noise of a crystal resonator or crystal oscillator with the frequency stability and accuracy of a TCXO or OCXO
External EEPROM support for autonomous initialization
Single 1.8 V power supply operation with internal regulation
Built in temperature monitor/alarm and temperature compensation for enhanced zero delay performance
