CCD Signal Processor with Vertical Driver
and Precision Timing ™ Generator
AD9925
FEATURES
GENERAL DESCRIPTION
Integrated 10-channel V-driver
The AD9925 is a complete 36 MHz front end solution for digi-
tal still camera and other CCD imaging applications. Based on
the AD9995 product, the AD9925 includes the analog front end
and a fully programmable timing generator (AFETG), combined
with a 10-channel vertical driver (V-driver). A Precision Timing
core allows adjustment of high speed clocks with approximately
600 ps resolution at 36 MHz operation.
Register-compatible with the AD9991 and AD9995
3-field (6-phase) vertical clock support
2 additional vertical outputs for advanced CCDs
Complete on-chip timing generator
Precision Timing core with <600 ps resolution
Correlated double sampler (CDS)
6 dB to 42 dB 10-bit variable gain amplifier (VGA)
12-bit 36 MHz ADC
Black level clamp with variable level control
On-chip 3 V horizontal and RG drivers
2-phase and 4-phase H-clock modes
The on-chip V-driver supports up to 10 channels for use with
3-field (6-phase) CCDs. Two additional vertical outputs can be
used with CCDs that contain advanced video readout modes.
Voltage levels of up to +15 V and −8 V are supported.
Electronic and mechanical shutter support
On-chip driver for external crystal
On-chip sync generator with external sync input
8 mm × 8 mm CSPBGA package with 0.65 mm pitch
The analog front end includes black level clamping, CDS, VGA,
and a 12-bit ADC. The timing generator and V-driver provide
all the necessary CCD clocks: RG, H-clocks, vertical clocks,
sensor gate pulses, substrate clock, and substrate bias control.
The internal registers are programmed using a 3-wire serial
interface.
APPLICATIONS
Digital still cameras
Digital video camcorders
CCD camera modules
Packaged in an 8 mm × 8 mm CSPBGA, the AD9925 is speci-
fied over an operating temperature range of −25°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM
REFT REFB
AD9925
6dB TO 42dB
VGA
0dB, –2dB, –4dB
CDS
VREF
12
12-BIT
ADC
CCDIN
DOUT
DCLK
CLAMP
INTERNAL CLOCKS
RG
PRECISION
TIMING
GENERATOR
HORIZONTAL
DRIVERS
MSHUT
4
H1 TO H4
STROBE
XV1 TO XV8
8
SL
V1, V2
V3A, V3B
V4, V6
V5A, V5B
V7, V8
INTERNAL
REGISTERS
10
SDI
SCK
XSG1 TO XSG6
6
VERTICAL
TIMING
CONTROL
V-DRIVER
SYNC
GENERATOR
SUBCK
RSTB
SUBCK
VSUB
HD
VD SYNC CLI CLO
Figure 1.
Rev. A
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