LP3918 Datasheet, PDF (5/30 Pages) National Semiconductor (TI) – Battery Charge Management and Regulator Unit

POWER SUPPLY CONFIGURATIONS
At PMU start up, LDO1, LDO2 and LDO3 are always started
with their default voltages. The start up sequence of the LDO's
is given below.
Startup Sequence
LDO1 -> LDO2 -> LDO3
LDO's with external enable control (LDO4, LDO5, LDO6) start
immediately after LDO2 if enabled by logic high at their re-
spective control inputs.
LDO7 (and LDO1 and 3) may be programmed to enable/dis-
able once PS_HOLD has been asserted.
Default voltages for the LDOs are shown in Table 1 and Table
2 shows the voltages that may be programmed via the Serial
Interface.
DEVICE PROGRAMMABILITY
An I²C compatible Serial Interface is used to communicate
with the device to program a series of registers and also to
read status registers. These internal registers allow control
over LDO outputs and their levels. The charger functions may
also be programmed to alter termination voltage, end of
charge current, charger restart voltage, full rate charge cur-
rent, and also the charging mode.
This device internal logic is powered from LDO2.
TABLE 1. LDO Default Voltages
LDO
1
2
3
4
5
6
7
Function mA
CORE
300
DIGI
300
ANA
80
TCXO
80
RX
150
TX
150
GP
150
Default Voltage (V)
1.8
3.0
3.0
3.0
3.0
3.0
3.0
Startup Default
ON
ON
ON
OFF
OFF
OFF
OFF
Enable Control
SI
-
SI
TCXO_EN
RX_EN
TX_EN
SI
LDO
1
CORE
2
DIGI
3
ANA
4
TCXO
5
RX
6
TX
7
GP
TABLE 2. LDO Output Voltages Selectable via Serial Interface
mA 1.5 1.8 1.85 2.5 2.6 2.7 2.75 2.8 2.85 2.9 2.95 3.0 3.05 3.1 3.2 3.3
300 + + + + + + + + + + + + + + + +
300
+++++++++++++
80
++++++++
80 + + + + + + + + + + + + + + + +
150
++++++++
150
++++++++
150 + + + + + + + + + + + + + + + +
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