IBIS4-6600 Datasheet, PDF (18/63 Pages) Cypress Semiconductor – High resolution 6.6 M Pixel Rolling shutter CMOS Image sensor

IBIS4-6600
Datasheet
3.5.4 Offset DACs
Figure 10 shows how the DAC registers influence the black reference voltages of the
two different channels. The offset is mainly given through DAC_raw. DAC_fine can
be used to shift the reference voltage of bus 2 up or down to compensate for different
offsets in the two channels.
DAC_RAW_REG<0:7>
DAC_raw
out
RCAL
+ _VCAL
rcal
pad RCAL_DAC_OUT
VDDA
50K
DAC_FINE_REG<0:7>
DAC_fine
out
50K
rcal
floating
GNDA
10K
200K
blackref
bus1
10K
200K
blackref
bus2
Figure 10: Offset for the two channels through DAC_raw and DAC_fine
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)
→
VDDA(1 − ¹ ) (bit values11111111)
2⁸
Externally, the output range of DAC_raw can be changed by connecting a resistor R_cal
to RCAL_DAC_OUT and applying a voltage V_cal. The output voltage V_out of DAC_raw
follows relation (R = 10 kΩ)
V_out
=
R + R_cal
2R + R_cal
V_outfull
+
R
2R + R_cal
V_cal
Special case: R_cal = ∞
then V_out = V_outfull (e.g. for DAC_fine)
Cypress Semiconductor Corporation 3901 North First Street
San Jose, CA 95134
408-943-2600
Contact: [e-mail] Document #: 38-05708 Rev.**(Revision 1.3 )
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