ADP5042

Manufacturer Part NumberADP5042
DescriptionMicro PMU with 0.8 A Buck, Two 300 mA LDOs, Supervisory, Watchdog and Manual Reset
ManufacturerAnalog Devices
ADP5042 datasheet
 


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ADP5042
THEORY OF OPERATION
VDDA
AVIN
GM ERROR
PWM
COMP
VIN1
I
LIMIT
PWM/
PSM
CONTROL
LOW
BUCK1
CURRENT
SW
DRIVER
AND
ANTISHOOT
THROUGH
PGND
POFF
MODE
MODE
ENABLE
EN1
ENBK
AND MODE
CONTROL
ENLDO1
EN2
ENLDO2
EN3
SEL
VDDA
OPMODE_FUSES
ADP5042
POWER MANAGEMENT UNIT
The ADP5042 is a micro power management unit (micro PMU)
combing one step-down (buck) dc-to-dc convertor, two low
dropout linear regulators (LDOs), and a supervisory circuit, with
dual watchdog, for processor control. The regulators are activated
by a logic level high applied to the respective EN pin. The EN1
controls the buck regulator, the EN2 controls LDO1, and the
EN3 controls LDO2. The ADP5042 has factory programmed
output voltages and reset voltage threshold. Other features
available in this device are the mode pin to control the buck
switching operation, a status pin informing the external processor
which watchdog caused a reset and push-button reset input.
When a regulator is turned on, the output voltage is controlled
through a soft start circuit to avoid a large inrush current due to
the discharged output capacitors.
VOUT1
MR
60Ω
ENBK
VDDA
AMP
52kΩ
SOFT START
PSM
COMP
R0
VDDA
OSCILLATOR
SYSTEM
UNDERVOLTAGE
LOCK OUT
THERMAL
SHUTDOWN
R1
LDO1
CONTROL
R2
VIN2
AGND VOUT2 VIN3
Figure 56. Functional Block Diagram
The buck regulator can operate in forced PWM mode if the
MODE pin is at a logic high level. In forced PWM mode, the
switching frequency of the buck is always constant and does not
change with the load current. If the MODE pin is at logic low
level, the switching regulator operates in auto PWM/PSM mode.
In this mode, the regulator operates at fixed PWM frequency
when the load current is above the power saving current threshold.
When the load current falls below the power saving current
threshold, the regulator enters power saving mode, where the
switching occurs in bursts. The burst repetition is a function of
the current load and the output capacitor value. This operating
mode reduces the switching and quiescent current losses.
Rev. A | Page 18 of 32
WMOD
WDI1
WDI2
40kΩ
ENWD1
ENWD2
WATCHDOG
WATCHDOG
DETECTOR1
DETECTOR2
POFF
200kΩ
WATCHDOG
STATUS
MONITOR
DEBOUNCE
R1
A
B
Y
RESET
C
GENERATOR
D
V
REF
500Ω
ENLDO2
R3
LDO2
VDDA
CONTROL
500Ω
R4
ENLDO1
Data Sheet
WSTAT
nRSTO
VOUT3