AR0833 Datasheet, PDF (12/64 Pages) ON Semiconductor – 8 Mp CMOS Digital Image Sensor

AR0833: 1/3.2-Inch 8 Mp CMOS Digital Image Sensor
Sensor Initialization
Sensor Initialization
Power-on Sequence
AR0833 has three voltage supplies divided into several domains. The three voltages are
1.2 V, 1.8 V, and 2.8 V. For proper operation of the chip, a power-up sequence is recom-
mended as shown in Figure 5.
The power sequence is governed by controlled vs controlling behavior of a power supply
and the inrush current (i.e., current that exists when not all power supplies are present).
Table 6:
Inrush consideration
XSHUTDOWN
x
x
x
x
x
x
0
1
1.2 V
Present
Absent
Absent
Present
Present
Absent
Present
Present
1.8 V
(VDDIO)
Absent
Present
Absent
Present
Absent
Present
Present
Present
2.8V
Absent
Absent
Present
Absent
Present
Present
Present
Present
Comment
Not supported
Supported
Supported
Supported
Not supported
Supported
Powered down state
Powered up state
Since VDD_IO supply controls the XSHUTDOWN, it should be turned on first. The
sequence of powering up the other two domains is not too critical. While turning on
2.8 V supply before 1.2 V supply shouldn't be an issue as shown in Table 1, it is still not
recommended since the 2.8 V domain is controlled by 1.2 V signals. The dedicated 1.8 V
domain is used only for OTPM read function, so can turn on along with 1.8 V supply.
Due to the above considerations, the suggested power-on sequence is as shown in
Figure 5 on page 13:
AR0833_DS Rev. H Pub. 4/15 EN
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