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Pin Descriptions
Connection Diagram
Analog Power
VA
The two VA pins are the analog supply pins.
They should be connected to a voltage
source of +5V and bypassed to AGND with a
0.1F monolithic capacitor in parallel with a
10F tantalum capacitor.
AGND
These two pins are the ground returns for
the analog supplies.
VD
This is the positive supply pin for the digital
I/O pins. It should be connected to a voltage
source between +3.3V and +5.0V and be
bypassed to DGND with a 0.1F monolithic
capacitor in parallel with a 10F tantalum
capacitor.
DGND
This is the ground return for the digital sup-
ply.
Analog Input/Output
OSR, OSG, OSB
Analog Inputs. These inputs (for Red,
Green, and Blue) should be tied to the sen-
sor’s OS (Output Signal) through DC block-
ing capacitors.
VREF+, VREFMID,
VREF-
Voltage reference bypass pins. VREF+,
VREFMID, and VREF- should each be
bypassed to AGND through a 0.1F mono-
lithic capacitor.
Timing Control
MCLK
Master clock input. The ADC conversion
rate will be 1/2 of MCLK. 12MHz is the max-
imum frequency for MCLK.
VSMP
Sample timing input signal. If VSMP is high
on the rising edge of MCLK, the input is
sampled on the rising edge of the next
MCLK. The reference signal for the next
pixel will be sampled one to four MCLKs
later, depending on the value in the
CDSREF configuration bits. If CDS is not
enabled, the internal reference will be sam-
pled during the reference sample time.
The number of MCLK cycles between
VSMP pulses determines the pixel rate.
Timing Diagrams 1 through 6 illustrate the
VSMP timings for all the valid pixel rates.
Note: See the applications section of the
datasheet for the proper timing relationships
between VSMP and MCLK.
CLMP
Clamp timing input. If CLMP and VSMP are
high on the rising edge of MCLK, all three
OS inputs will be internally connected to
VCLAMP during the next pixel. VCLAMP is either
VREF+ or VREF- depending on the state of
the Signal Polarity bit in the Sample Mode
register (Reg. 0, Bit 4).
Data Output
D7
-D0
Data Output pins. The 16 bit conversion
results of the ADC are multiplexed in 8 bit
bytes to D7-D0 synchronous with MCLK.
The MSB consists of data bits d15-d8 on
pins D7-D0 and the LSB consists of d7-d0
on pins D7-D0.
Serial Input/Output
SCLK
Serial Shift Clock. Input data on SDI is valid
on the rising edge of SCLK. The minimum
SCLK period is 1 tMCLK.
SDO
Serial Data Output. Data bits are shifted out
of SDO on falling edges of SCLK. The first
eight falling edges of SCLK after SEN goes
low will shift out eight data bits (MSB first)
from the configuration register addressed
during the previous SEN low time.
SDI
Serial Data Input. A read/write bit, followed
by a four address bits and eight data bits is
shifted into SDI, MSB first. Data should be
valid on the rising edge of SCLK. If the
read/write bit is a “0” (a write), then the
shifted data bits will be stored. If the
read/write bit is a “1” (a read), then the data
bits will be ignored, and SDO will shift out
the addressed register’s contents during the
next SEN low time.
SEN
Shift enable and load signal. When SEN is
low, data is shifted into SDI. When SEN
goes high, the last thirteen bits (one
read/write, four address and eight data)
shifted into SDI will be used to program the
addressed configuration register. SEN must
be high for at least 3 MCLK cycles between
SEN low times.
LM9823
28 pin
SOIC
SCLK
SDI
SEN
D2
D0
VD
DGND
D4
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
9
10
23
22
21
24
25
26
27
28
D7
D6
D5
MCLK
VA
VREF-
OSB
OSG
CLMP
OSR
VREF+
AGND
VSMP
SDO
VREFMID
VBANDGAP
D3
D1
LM
9823