LP3971 Datasheet, PDF (32/42 Pages) National Semiconductor (TI) – POWER MANAGEMENT UNIT FOR ADVANCED APPLICATION PROCESSORS

I ²C Register Definitions (Continued)
VCC_LDO5 VOLTAGE CONTROL REGISTER (L5VCR) 8h’3B
Bit
7
6
5
4
Designation
Reserved
Reset Value
0
0
0
0
3
2
1
0
LDO 5 Output Voltage (L5OV)
0
0
1
0
VCC_LDO5 VOLTAGE CONTROL REGISTER (L5VCR) 8h’3B DEFINITIONS
Bit Access
7:5
...
4:0
R/W
Name
...
B1OV
Reserved
Data Code
4h’0
4h’1
4h’2
4h’3
4h’4
4h’5
4h’6
4h’7
4h’8
4h’9
4h’A
4h’B
4h’C
4h’D
4h’E
4h’F
Description
Output Voltage
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.50
1.80
1.90
2.50
2.80
3.00
3.30
Serial interface register selection codes (Bold face voltages are default values).
Register Programming Examples
Example 1. Setting register 8h’12 value to 8h’3E’ will enable LDOs 1–5.
Example 2. Setting register 8h’39 to 8h’CC’ will set LDOs 1 and 2 to 3.0V. These voltages will appear at the LDO outputs if the
corresponding LDO has been enabled. Programming a voltage value to a LDO, which is off, will affect the LDO output voltage
after the LDO is enabled. Enabling and programming the output voltage are separate operations.
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