NOII5FM1300A-QDC ON Semiconductor, NOII5FM1300A-QDC Datasheet - Page 12
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NOII5FM1300A-QDC
Manufacturer Part Number
NOII5FM1300A-QDC
Description
Manufacturer
ON Semiconductor
Datasheet
1.NOII5FM1300A-QDC.pdf
(34 pages)
Specifications of NOII5FM1300A-QDC
Lead Free Status / Rohs Status
Supplier Unconfirmed
Output Amplifier
Architecture and Settings
The output amplifier stage is user programmable for gain and
offset level. Gain is controlled by 4-bit wide word; offset by a 7-bit
wide word. Gain settings are on an exponential scale. Offset is
controlled by a 7-bit wide DAC, which selects the offset voltage
between
DAC_VLOW) on a linear scale.
The amplifier is designed to match the specifications of the
imager array output. This signal has a data rate of 40 MHz. The
output impedance of the amplifier is 260 Ohms.
At unity gain and with a mid-range offset value, the amplifier
outputs a signal in between 1.59 V (light) and 2.70 V (dark). This
analog range must fit to the input range of the ADC, external or
internal. The output swing in unity gain is approximately 1.11 V
and it is maximum 1.78 V at the highest gain settings. So, the
effective signal range is between 1.17 V and 2.95 V, depending
on the gain and offset settings of the amplifier.
Figure 11. Output Structure
Figure 11
and even column amplifiers sample both pixel and reset value to
perform a double sampling FPN correction. You can adjust two
different offsets using the on-chip DAC (7 bit): DAC_FINE and
DAC_RAW. DAC_FINE is used to tune the difference between
odd and even columns; DAC_RAW is used to add a common
(both even and odd columns) to the FPN corrected pixel value.
This pixel value is fed to the first amplifier stage which has an
adjustable gain, controlled by a 4-bit word (’GAIN [0…3]’).
After this, a unity feedback amplifier buffers the signal and the
signal leaves the chip. This second amplifier stage determines
the maximal readout speed, that is, the bandwidth and the slew
rate of the output signal. The whole amplifier chain is designed
for a data rate of 40 Mpix/s (at 20 pF).
The analog output of the sensor is not designed to drive very
large loads on the PCB. Therefore, it is advised that the
PXL_OUT is connected to the ADC_IN right below the sensor in
the top layer with a thick track. It is better not to have vias on this
trace. If there is a socket being used, then it is advised that we
buffer the PXL_OUT close to the sensor output pin and then take
the signal to the ADC_IN.
DAC_RAW [6:0]
odd
even
DAC_FINE [6:0]
DAC_VHIGH
DAC_VLOW
S
R
S
R
shows the architecture of the output amplifier. The odd
two
+
DAC_FINE
reference
DAC_RAW
+
voltages
GAIN [0…3]
unity gain
A
(DAC_VHIGH
Rev. 9 | www.onsemi.com | Page 12 of 34
1
PXL_OUT
and
Output Amplifier Gain Control
The output amplifier gain is controlled by a 4-bit word set in the
AMPLIFIER register (see section
page 19). An overview of the gain settings is given in
Table 13. Overview Gain Settings
Setting of the DAC Reference Voltage
In the output amplifier, the offset is trimmed by loading registers
DACRAW_REG and DACFINE_REG. DAC_RAW is used to
adjust the offset of the output amplifier and DAC_FINE is used
to tune the offset between the even and odd columns. These
registers are inputs for two DACs (see
the same resistor that is connected between pins DAC_VHIGH
and DAC_VLOW. The range of the DAC is defined using a
resistive division with R
Figure 12. Internal and External ADC Connections
The internal resistor R
The recommend resistor values for both DAC_VLOW and
DAC_VHIGH are 0 .
D A C _V H IG H = 3.3V
D A C _V LO W = 0V
0000
0001
0010
0011
0100
0101
0110
0111
Bits
R
D A C
DAC
DC Gain
VHIGH
1.37
1.62
1.96
2.33
2.76
3.50
4.25
5.20
has a value of approximately 7.88 k.
R
7.88 kΩ
R
external
external
D A C _V H IG H
D A C _V LOW
internal
internal
, R
DAC
Amplifier Register (6:0)
and R
Figure
NOII5SM1300A
1000
1001
1010
1011
1100
1101
1110
1111
Bits
VLOW.
12) that operate on
DC Gain
11.00
11.37
11.84
12.32
12.42
6.25
7.89
9.21
Table
13.
on