
Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com
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XRD9836
16-BIT PIXEL GAIN AFE
JUNE 2003
REV. 1.0.0
GENERAL DESCRIPTION
The XRD9836 is a precision 16-bit analog front-end
(AFE) for use in 3-channel/1-channel CCD/CIS docu-
ment imaging applications. Pixel-by-pixel gain and
offset for each of the 3 channels are controlled using
a time multiplexed parallel input. Offset and Gain are
sequentially supplied for red, green, and blue. The
outputs from each of the three channels are transmit-
ted time multiplexed with the high order byte first fol-
lowed by the low order byte for red, blue and green.
FEATURES
16-bit resolution ADC, 30MHz Sampling Rate
10-bit accurate linear programmable gain range select-
able as either 2-to-20 V/V or 1-to-10 V/V per channel
Fully-differential input pins and internal path
Sampling rates from 1.0 MSPS to 10.0 MSPS per chan-
nel for 3 -Channel mode and up to 15.0 MSPS in single
channel mode.
Pixel-by-Pixel Offset and Gain control through a parallel
interface running at a maximum 60 Mbyte/sec. data rate
A microprocessor serial port to control various modes of
operation
Fixed Gain/Offset Mode (FGOM) or Pixel by Pixel Gain/
Offset Mode (PPGOM)
Alternate Pixel Offset Adjust Mode (APOAM)
Low Power CMOS=280mW (typ. @ 3V); Power-Down
Mode=1mW (typ. @ 3V with static clocks)
Single Power Supply (3.0 to 3.6 Volts) with Max CCD
input signal of 1V and reset pulse up to 0.5V
High ESD Protection: 2000 Volts Minimum
APPLICATIONS
Scanners, MFP’s
FIGURE 1. BLOCK DIAGRAM
POWER
BIAS
SERIAL PORT
TIMING
SCLK
SDATA
LOAD
VSAMP
BSAMP
LCLMP
CAPP
Avdd
3
RED+
16
16-BIT
30MHz
ADC
M
U
X
BLUE
CDS &
PGA
Blue Gain
Blue Offset
D
E
M
U
X
Red Gain
Red Offset
Green Gain
Green Offset
BLUE HIGH ORDER
ADC OUT
BLUE LOW ORDER
ADC OUT
8
ADC
OUT
IE
10
ADCLK
RED GAIN
REGISTER
RED OFFSET
REGISTER
10
OFFSET/GAIN
INPUT
2
XRD9836
ANALOG INPUTS
Agnd
Dvdd Dgnd
Ovdd
Ognd
GREEN HIGH ORDER
ADC OUT
GREEN LOW ORDER
ADC OUT
RED HIGH ORDER
ADC OUT
RED LOW ORDER
ADC OUT
RED
CDS &
PGA
Green
CDS &
PGA
GREEN GAIN
REGISTER
GREEN OFFSET
REGISTER
BLUE GAIN
REGISTER
BLUE OFFSET
REGISTER
RED-
GRN+
GRN-
BLUE-
BLUE+
CAPN
CMREF
REXT