
Analog Devices
GENERAL DESCRIPTION
The AD9508 provides clock fanout capability in a design that emphasizes low jitter to maximize system performance. This device benefits applications like clocking data converters with demanding phase noise and low jitter requirements.
There are four independent differential clock outputs, each with various types of logic levels available. Available logic types include LVDS (1.65 GHz), HSTL (1.65 GHz), and 1.8 V CMOS (250 MHz). In 1.8 V CMOS output mode, the differential output becomes two CMOS single-ended signals. The CMOS outputs are 1.8 V logic levels, regardless of the operating supply voltage.
FEATURES
1.65 GHz differential clock inputs/outputs
10-bit programmable dividers, 1 to 1024, all integers
Up to 4 differential outputs or 8 CMOS outputs
Pin strapping capability for hardwired programming at
power-up
<115 fs rms broadband random jitter (see Figure 25)
Additive output jitter: 41 fs rms typical (12 kHz to 20 MHz)
Excellent output-to-output isolation
Automatic synchronization of all outputs
Single 2.5 V/3.3 V power supply
Internal LDO (low drop-out) voltage regulator for enhanced
power supply immunity
Phase offset select for output-to-output coarse delay adjust
3 programmable output logic levels, LVDS, HSTL, and CMOS
Serial control port (SPI/I2C) or pin-programmable mode
Space-saving 24-lead LFCSP
APPLICATIONS
Low jitter, low phase noise clock distribution
Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs
High performance wireless transceivers
High performance instrumentation
Broadband infrastructure