IBIS4-6600 CYII4SM6600AB
Document Number: 001-02366 Rev. *E
Page 11 of 35
Assume that Voutfull is the voltage that depends on the bit values that are applied to the DAC and ranges from:
Externally, the output range of DAC_raw can be changed by connecting a resistor Rcal to RCAL_DAC_OUT and applying a voltage
Vcal. The output voltage Vout of DAC_raw follows the relation (R = 10 kΩ).
Special case:
Rcal = then Vout = Voutfull (for example, for DAC_fine)
Rcal = 0, Vcal = GND ............................. then Vout = Voutfull/2
A similar relation holds for the output range of DAC_DARK (RCAL_DAC_DARK can be used to tune the output range of this DAC).
Analog to Digital Converter
The IBIS4-6600 has a two 10-bit flash analog digital converters. The ADCs are electrically separated from the image sensor. The
inputs of the ADC must be tied externally to the outputs of the output amplifiers. One ADC samples the even columns and the other
samples the odd columns. Alternatively, one ADC can also sample all the pixels.
Setting the ADC Reference Voltages
Figure 12. ADC Resistor Ladder
The internal resistance has a value of approximately 577
Ω. Only
277
Ω of this internal resistance is actually used as reference for
the internal ADC. This causes the actual ADC voltage range to
become half of the voltage difference between VHIGH_ADC and
VLOW_ADC. This results in the values listed Table 6 for the
external resistors.
Table 5. ADC Specifications
Parameter
Specification
Input Range
Set by External Resistors
(Refer the section Setting the ADC Reference Voltages)
Quantization
10 Bits
Nominal Data Rate
20 Msamples/s
DNL(Linear Conversion Mode)
Typ. < 0.4 LSB RMS
INL (Linear Conversion Mode)
Typ. < 3.5 LSB
Input Capacitance
< 2 pF
Conversion Law
Linear/Gamma corrected
)
11111111
(
)
2
1
1
(
)
00000000
(
0
:
8
values
bit
VDDA
values
bit
Voutfull
cal
cal
outfull
cal
cal
out
V
R
R
R
V
R
R
R
R
V
2
2
150 Ohm (ESD)
RADC = 577 Ohm
Internal
GND
VLOW_ADC ~ 0.42V
VHIGH_ADC ~ 1.5V
277 Ohm
VDDA_ADC
High reference voltage
used by ADC
150 Ohm (ESD)
Low reference voltage
used by ADC
Table 6. ADC Resistor Values
Resistor
Value (
Ω)
RVHIGH_ADC
560
RInternal
577
RVLOWADC
220
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