
Analog Devices
GENERAL DESCRIPTION
The AD9524 provides a low power, multi-output, clock distribution function with low jitter performance, along with an on-chip PLL and VCO. The on-chip VCO tunes from 3.6 GHz to 4.0 GHz. The AD9524 is defined to support the clock requirements for long term evolution (LTE) and multicarrier GSM base station designs. It relies on an external VCXO to provide the reference jitter cleanup to achieve the restrictive low phase noise require ments necessary for acceptable data converter SNR performance.
FEATURES
Output frequency: <1 MHz to 1 GHz
Start-up frequency accuracy: <±100 ppm (determined by VCXO reference accuracy)
Zero delay operation
Input-to-output edge timing: <±150 ps
6 outputs: configurable LVPECL, LVDS, HSTL, and LVCMOS
6 dedicated output dividers with jitter-free adjustable delay
Adjustable delay: 63 resolution steps of ½ period of VCO output divider
Output-to-output skew: <±50 ps
Duty-cycle correction for odd divider settings
Automatic synchronization of all outputs on power-up
Absolute output jitter: <200 fs at 122.88 MHz
Integration range: 12 kHz to 20 MHz
Distribution phase noise floor: −160 dBc/Hz
Digital lock detect
Nonvolatile EEPROM stores configuration settings
SPI- and I²C-compatible serial control port
Dual PLL architecture
PLL1
Low bandwidth for reference input clock cleanup with external VCXO
Phase detector rate of 300 kHz to 75 MHz
Redundant reference inputs
Auto and manual reference switchover modes
Revertive and nonrevertive switching
Loss of reference detection with holdover mode
Low noise LVCMOS output from VCXO used for RF/IF synthesizers
PLL2
Phase detector rate of up to 250 MHz
Integrated low noise VCO
APPLICATIONS
LTE and multicarrier GSM base stations
Wireless and broadband infrastructure
Medical instrumentation
Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs
Low jitter, low phase noise clock distribution
Clock generation and translation for SONET, 10Ge, 10G FC, and other 10 Gbps protocols
Forward error correction (G.710)
High performance wireless transceivers
ATE and high performance instrumentation