GENERAL DESCRIPTION

The AD9520-51 provides a multioutput clock distribution function with subpicosecond jitter performance, along with an on-chip PLL that can be used with an external VCO.

The AD9520-5 serial interface supports both SPI and I²C ports. An in-package EEPROM, which can be programmed through the serial interface, can store user-defined register settings for power-up and chip reset.

The AD9520-5 features 12 LVPECL outputs in four groups. Any of the 1.6 GHz LVPECL outputs can be reconfigured as two 250 MHz CMOS outputs. If an application requires LVDS drivers instead of LVPECL drivers, refer to the AD9522-5.

Each group of three outputs has a divider that allows both the divide ratio (from 1 to 32) and the phase offset or coarse time delay to be set.

The AD9520-5 is available in a 64-lead LFCSP and can be operated from a single 3.3 V supply. The external VCO can have an operating voltage of up to 5.5 V. A separate output driver power supply can be from 2.375 V to 3.465 V.

The AD9520-5 is specified for operation over the standard industrial range of −40°C to +85°C.

FEATURES

Low phase noise, phase-locked loop (PLL)

Optional external 3.3 V/5 V VCO/VCXO to 2.4 GHz

1 differential or 2 single-ended reference inputs

Accepts CMOS, LVDS, or LVPECL references to 250 MHz

Accepts 16.62 MHz to 33.3 MHz crystal for reference input

Optional reference clock doubler

Reference monitoring capability

Automatic/ manual reference holdover and reference

switchover modes, with revertive switching

Glitch-free switchover between references

Automatic recovery from holdover

Digital or analog lock detect, selectable

Optional zero delay operation

Twelve 1.6 GHz LVPECL outputs divided into 4 groups

Each group of 3 outputs shares a 1-to-32 divider with

phase delay

Additive output jitter as low as 225 fs rms

Channel-to-channel skew grouped outputs < 16 ps

Each LVPECL output can be configured as 2 CMOS outputs

(for fOUT ≤ 250 MHz)

Automatic synchronization of all outputs on power-up

Manual output synchronization available

SPI- and I²C-compatible serial control port

64-lead LFCSP

Nonvolatile EEPROM stores configuration settings

APPLICATIONS

Low jitter, low phase noise clock distribution

Clock generation and translation for SONET, 10Ge, 10GFC,

Synchronous Ethernet, OTU2/3/4

Forward error correction (G.710)

Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs

High performance wireless transceivers

ATE and high performance instrumentation

Broadband infrastructures