
REV. 0
–26–
ADP3502
LDO Control
The LDO control block controls Power ON/OFF of the LDO
block. The function in this block has:
Hardware control using external signals
Software control using serial interface
A mixture of the hardware and software above
LDO1, LDO2, LDO3, and LDO6 are structured with main and
sub-LDOs. LDO4, LDO5, LDO7, LDO8, LDO9, LDO10, and
LDO11 are set through the serial interface, but LDO7 and LDO9
are gated (AND gate) with SLEEP– signal in order to get into
the SLEEP mode. If the SLEEP– signal is enabled (goes low), the
outputs of LDO7 and LDO9 are turned OFF. The Power ON
Logic controls the remainder of the LDOs, including LDO1,
LDO2, and LDO6. A sub-LDO called LDO3b is independently
controlled, and this LDO control block doesn’t control LDO3b.
Also, the main LDO3, called LDO3a, is turned on by the Power
ON signal, but the sub-LDO3, called LDO3b, is always ON
while the battery supplies, and only the DDLO controls LDO3b.
A DDLO is the control signal from the battery charger block and
is monitoring the battery voltage. When VBAT is under 2.5 V
(200 mV hysteresis from VBAT = 2.7 V), DDLO minimizes
(DDLO enable) the current flow from the Li-Ion battery.
Main LDOs: LDO1a, LDO2a, LDO3a, LDO6a
Sub-LDOs: LDO1b, LDO2b, LDO3b, LDO6b
Table IVa. DDLO Status Table
Status
LDO1a
LDO1b
LDO2a
LDO2b
LDO3a
LDO3b
LDO4
REFO
LDO5
LDO6a
LDO6b
LDO7
LDO8
LDO9
LDO10
LDO11
RF
Option
Baseband VDD
Baseband AVDD
Coin Cell
Audio
REFO
Vibrator
Baseband Core
Rx1
Tx
Rx2
Option
DDLO
Enable
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
DDLO
Disable
X
X
X
X
X
ON
X
X
X
X
X
X
X
X
X
X
X means a status of LDO depends on other conditions.
Table IVb. LDO Control Event Table
1
Event
LDO1a LDO1b
LDO2a
LDO2b
LDO3a
LDO3b
LDO4
REFO
LDO5
LDO6a LDO6b
LDO7
LDO8
LDO9
LDO10
LDO11
RF
Option
Baseband VDD
Baseband AVDD
Coin Cell
Audio
REFO
Vibrator
Baseband Core
Rx1
Tx
Rx2
Option
Power ON
2
ON
ON
ON
ON
ON
ON
ON
ON
ON
TCXOON
3
ON/
ON/
ON/
ON/
OFF
OFF
OFF
OFF
SLEEP–
4
ON/
ON/
OFF
OFF
RESETIN–
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
ALLOFF Bit
Goes “H”
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
PWROFF Bit
Goes “H”
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
NOTES
1
This table indicates only the status change caused by an event. Blank cells mean no change and keep previous status.
2
Power-ON Event: Indicating a status just after the power-ON event. After the event, a status of LDO1a, LDO2a, LDO3a, and LDO6a are changed by the
TCXOON signal.
3
TCXOON: Hardware control, change all main LDOs’ ON/OFF status.
4
SLEEP–: The LDO7 and LDO9 can be controlled by software if SLEEP = “H” level. If SLEEP– goes “L,” these LDOs are turned OFF immediately.
Table IVc. Software Controllability of LDOs
LDO
LDO1a LDO1b
LDO2a
LDO2b
LDO3a LDO3b
LDO4
REFO
LDO5
LDO6a LDO6b
LDO7
LDO8
LDO9
LDO10
LDO11
Description Baseband VDD
Baseband AVDD
Coin Cell
Audio
REFO
Vibrator
Baseband Core
Rx1
Tx
Rx2
RF Option
Option
Software
Turn ON
√
√
√
√
*
√
√
*
√
√
Software
Turn OFF
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
*
LDO7 and LDO9 have a gate with SLEEP–. If SLEEP– is in “L” (active) status, users cannot control it and both LDOs are kept in an OFF status. Users may want to use this
function as an immediate control to get OFF status by using SLEEP– hardware control when setting Register “1” to the LDO control register.