High Speed, Correlated Double Sampler
with Integrated Timing Driver
AD9940
FEATURES
GENERAL DESCRIPTION
56 MSPS correlated double sampler (CDS) with 6 dB gain
On-chip horizontal and RG timing driver
Single-supply operation (2.7 V min )
Precision Timing™ core with 0.37 ns resolution at 56 MSPS
Low power CMOS: 105 mW at 2.7 V (115 mW at 3.0 V)
48-lead LQFP and 48-lead LFCSP packages
The AD9940 is a high speed, correlated double sampler for
high speed digital imaging applications. Integrated with a
programmable timing driver using the Precision Timing
core, the AD9940 features a 56 MHz CDS amplifier with
6 dB of fixed gain, an internal voltage reference supply,
and timing control for all the high speed clocks necessary
for CCD imaging systems. The Precision Timing core allows
adjustment of high speed clocks with a resolution of 0.37 ns.
Output buffers are also included, providing drive strength for
PCB traces and direct connection to an image signal processor
such as the AD9941.
APPLICATIONS
Professional HDTV camcorders
Professional/high end digital cameras
Broadcast cameras
Industrial high speed cameras
High speed data-acquisition systems
The AD9940 is ideal for applications that need to place the
CDS and VGA/ADC circuits on separate PC boards. The fully
differential outputs of the AD9940 provide good signal integ-
rity when interfaced with the differential input AD9941. The
AD9940 operates from a single 2.7 V power supply, typically
dissipates 105 mW (excluding the H/RG drive current), and is
packaged in 48-lead LQFP and 48-lead LFCSP packages.
FUNCTIONAL BLOCK DIAGRAM
REFT REFB
AD9940
V
REF
DIFFN
DIFFP
CCDIN
CDS
BUF
INTERNAL
CLOCKS
RG
HL
PRECISION
TIMING
GENERATOR
HORIZONTAL
DRIVERS
RST
4
H1 TO H4
SYNC
INTERNAL
GENERATOR
REGISTERS
CLI
HD SHP SHD
SL
SCK SDI
.
Figure 1.
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2005 Analog Devices, Inc. All rights reserved.