AD9508 Datasheet, PDF (1/40 Pages) Analog Devices – 1.65 GHz Clock Fanout Buffer with Output Dividers and Delay Adjust

Data Sheet
1.65 GHz Clock Fanout Buffer with
Output Dividers and Delay Adjust
AD9508
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
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.
FUNCTIONAL BLOCK DIAGRAM
AD9508
CLK
CLK
DIV/Φ
DIV/Φ
DIV/Φ
SCLK/SCL/SC0
SDIO/SDA/S1
SDO/S3
CS/C2
CONTROL
INTERFACE
SPI/I²C/PINS
DIV/Φ
OUT0
OUT0
OUT1
OUT1
OUT2
OUT2
OUT3
OUT3
PIN CONTROL RESET
Figure 1.
SYNC
Each output has a programmable divider that can be bypassed
or be set to divide by any integer up to 1024. In addition, the
AD9508 supports a coarse output phase adjustment between the
outputs.
The device can also be pin programmed for various fixed
configurations at power-up without the need for SPI or I2C
programming.
The AD9508 is available in a 24-lead LFCSP and operates from
a either a single 2.5 V or 3.3 V supply. The temperature range is
−40°C to +85°C.
Rev. A
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