... the analog plusTM compa
EXAR Corporation 48720 Kato Road, Fremont, CA 94538 Phone
PRELIMINARY
XRD9827
1.24V
VDD
BANDGAP
C
I
S
| 12K | VRT |
|
| |
PIN 19 |
|
|
(RED) | M |
|
| RL | |
PIN 16 | U | |
(VDCEXT) | X |
|
2.2uF
VRB
Figure 7. Simplified Block Diagram Showing Global Offset Adjustment by XRD9827 Using Internal Bandgap and CIS Using VDCEXT for Biasing
18.Set the dip switches to [001 01010000] to select the internal offset DAC for fine offset adjustment. Push the Serial Port button. From the CAPTURE menu select SNAP SHOT. The offset should now move the output of the CIS to almost zero scale. The other way to do a SNAP SHOT is by pressing CTRL and B button at the same time. Please refer to data sheet for offset adjustment. A typical result of the fine offset adjustment is shown below.
10
