IBIS4-6600_09 Datasheet, PDF (11/35 Pages) Cypress Semiconductor – 6.6 MP CMOS Image Sensor

IBIS4-6600 CYII4SM6600AB
Assume that V_outfull is the voltage that depends on the bit values that are applied to the DAC and ranges from:
V_outfull : 0 (bit values 00000000 )
o
VDDA
(1

1
2⁸
)
(bit values 11111111 )
Externally, the output range of DAC_raw can be changed by connecting a resistor Rcal to RCAL_DAC_OUT and applying a voltage
V_cal. The output voltage V_out of DAC_raw follows the relation (R = 10 kΩ).
V_out
R  R_cal
2R  R_cal
V_outfull

2R
R
 R_cal
V_cal
Special case:
R_cal = then V_out = V_outfull (for example, for DAC_fine)
Rcal = 0, Vcal = GND ............................. then V_out = V_outfull/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.
Table 5. ADC Specifications
Input Range
Parameter
Quantization
Nominal Data Rate
DNL(Linear Conversion Mode)
INL (Linear Conversion Mode)
Input Capacitance
Conversion Law
Specification
Set by External Resistors
(Refer the section Setting the ADC Reference Voltages)
10 Bits
20 Msamples/s
Typ. < 0.4 LSB RMS
Typ. < 3.5 LSB
< 2 pF
Linear/Gamma corrected
Setting the ADC Reference Voltages
Figure 12. ADC Resistor Ladder
VDDA_ADC
VHIGH_ADC ~ 1.5V
VLOW_ADC ~ 0.42V
RADC = 577 Ohm
Internal
150 Ohm (ESD)
277 Ohm
High reference voltage
used by ADC
Low reference voltage
used by ADC
150 Ohm (ESD)
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 6. ADC Resistor Values
Resistor
RVHIGH_ADC
RInternal
RVLOWADC
Value (Ω)
560
577
220
GND
Document Number: 001-02366 Rev. *E
Page 11 of 35
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