Dual 3 MHz, 800 mA Buck
Regulators with Two 300 mA LDOs
ADP5037
Data Sheet
load is above a predefined threshold, the buck regulators
operate in PWM mode. When the load current falls below a
predefined threshold, the regulator operates in power save
mode (PSM), improving the light-load efficiency.
FEATURES
Main input voltage range: 2.3 V to 5.5 V
Two 800 mA buck regulators and two 300 mA LDOs
24-lead, 4 mm × 4 mm LFCSP package
Regulator accuracy: ±1.8%
Factory programmable or external adjustable VOUTx
3 MHz buck operation with forced PWM and auto PWM/PSM
modes
BUCK1/BUCK2: output voltage range from 0.8 V to 3.8 V
LDO1/LDO2: output voltage range from 0.8 V to 5.2 V
LDO1/LDO2: input supply voltage from 1.7 V to 5.5 V
LDO1/LDO2: high PSRR and low output noise
Table 1. Family Models
APPLICATIONS
Power for processors, ASICS, FPGAs, and RF chipsets
Portable instrumentation and medical devices
Space constrained devices
Model
ADP5023
Channels
2 Buck, 1 LDO
ADP5024
2 Buck, 1 LDO
ADP5034
2 Buck, 2 LDOs
ADP5037
2 Buck, 2 LDOs
ADP5033
2 Buck, 2 LDOs with
2 EN pins
Maximum
Current
800 mA,
300 mA
1.2 A,
300 mA
1.2 A,
300 mA
800 mA,
300 mA
800 mA,
300 mA
Package
LFCSP (CP-24-10)
LFCSP (CP-24-10)
LFCSP (CP-24-10),
TSSOP (RE-28-1)
LFCSP (CP-24-10)
WLCSP (CB-16-8)
The two bucks operate out of phase to reduce the input capacitor requirement. The low quiescent current, low dropout voltage,
and wide input voltage range of the ADP5037 LDOs extend the
battery life of portable devices. The ADP5037 LDOs maintain
power supply rejection greater than 60 dB for frequencies as
high as 10 kHz while operating with a low headroom voltage.
GENERAL DESCRIPTION
The ADP5037 combines two high performance buck regulators
and two low dropout (LDO) regulators in a small, 24-lead 4 mm ×
4 mm LFCSP to meet demanding performance and board space
requirements.
Regulators in the ADP5037 are activated though dedicated
enable pins. The default output voltages can be externally set in
the adjustable version or factory programmable to a wide range
of preset values in the fixed voltage version.
The high switching frequency of the buck regulators enables tiny
multilayer external components and minimizes the board space.
When the MODE pin is set high, the buck regulators operate in
forced PWM mode. When the MODE pin is set low and the
TYPICAL APPLICATION CIRCUIT
AVIN
CAVIN
0.1µF
2.3V TO
5.5V
HOUSEKEEPING
VOUT1
VIN1
SW1
C1
4.7µF
ON
OFF
BUCK1
EN1
FB1
PGND1
EN1
L1 1µH
C5
10µF
R2
MODE
PWM
MODE
MODE
SW2
C2
4.7µF
BUCK2
EN3
EN2
EN3
VIN3
1.7V TO
5.5V
FB2
PGND2
R4
C6
10µF
FB3
R5
VOUT3 AT
300mA
C7
1µF
VOUT4
EN4
LDO2
(DIGITAL)
FB4
R7
R8
ADP5037
AGND
VOUT4 AT
300mA
C8
1µF
09887-001
VIN4
VOUT2 AT
800mA
R3
R6
EN4
OFF
C4
1µF
L2 1µH
VOUT3
LDO1
(ANALOG)
C3
1µF
ON
PSM/PWM
VOUT2
VIN2
EN2
VOUT1 AT
800mA
R1
Figure 1.
Rev. D
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Technical Support
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ADP5037
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Theory of Operation ...................................................................... 15
Applications ....................................................................................... 1
Power Management Unit........................................................... 15
General Description ......................................................................... 1
BUCK1 and BUCK2 .................................................................. 17
Typical Application Circuit ............................................................. 1
LDO1 and LDO2 ........................................................................ 18
Revision History ............................................................................... 2
Applications Information .............................................................. 19
Specifications..................................................................................... 3
Buck External Component Selection....................................... 19
General Specifications ................................................................. 3
LDO External Component Selection....................................... 21
BUCK1 and BUCK2 Specifications ........................................... 4
Power Dissipation and Thermal Considerations ....................... 22
LDO1 and LDO2 Specifications ................................................. 4
Buck Regulator Power Dissipation .......................................... 22
Input and Output Capacitor, Recommended Specifications .. 5
Junction Temperature ................................................................ 23
Absolute Maximum Ratings ............................................................ 6
PCB Layout Guidelines .................................................................. 24
Thermal Resistance ...................................................................... 6
Typical Application Schematics .................................................... 25
ESD Caution .................................................................................. 6
Bill of Materials ............................................................................... 26
Pin Configuration and Function Descriptions ............................. 7
Outline Dimensions ....................................................................... 27
Typical Performance Characteristics ............................................. 8
Ordering Guide .......................................................................... 27
REVISION HISTORY
5/13—Rev. C to Rev. D
Added Table 1; Renumbered Sequentially .................................... 1
Changes to Figure 1 .......................................................................... 1
Changes to NC Pin Description ..................................................... 7
Changes to Figure 48 ...................................................................... 18
Changes to Figure 50 ...................................................................... 20
Changes to Figure 52 and Figure 53............................................. 25
1/13—Rev. B to Rev. C
Changes to Figure 9 .......................................................................... 9
Changes to Ordering Guide .......................................................... 27
8/12—Rev. A to Rev. B
Changes to Regulator Accuracy, Features Section ....................... 1
Changes to Output Voltage Accuracy, Table 2 and Voltage
Feedback, Table 2 .............................................................................. 4
Changes to Output Voltage Accuracy, Table 3 and Voltage
Feedback, Table 3 .............................................................................. 4
Changes to Figure 6, Figure 7, and Figure 8.................................. 8
Changes to Figure 9 to Figure 14 .................................................... 9
Changes to Figure 30 and Figure 31............................................. 12
Changes to Figure 34 and Figure 38 Caption ............................. 13
Changes to Undervoltage Lockout Section ................................. 16
Moved Power Dissipation and Thermal Considerations
Section .............................................................................................. 22
Changes to Buck Regulator Power Dissipation Section ............ 22
Changes to PCB Layout Guidelines Section ............................... 24
Changes to Ordering Guide .......................................................... 27
1/12—Rev. 0 to Rev. A
Changes to Features Section and Figure 1 .....................................1
Changes to Table 2 and Table 3........................................................4
Changes to Table 4.............................................................................5
Changes to Table 5.............................................................................6
Changes to Table 7.............................................................................7
Changes to Figure 34...................................................................... 13
Changes to Buck Regulator Power Dissipation Section ............ 15
Changes to Undervoltage Lockout Section ................................. 18
Changes to LDO1 and LDO2 Section ......................................... 20
Changes to Table 9.......................................................................... 22
Changes to Figure 52 and Figure 53 ............................................ 25
Changes to Ordering Guide .......................................................... 27
8/11—Revision 0: Initial Version
Rev. D | Page 2 of 28
Data Sheet
ADP5037
SPECIFICATIONS
GENERAL SPECIFICATIONS
VAVIN = VIN1 = VIN2 = 2.3 V to 5.5 V; VIN3 = VIN4 = 1.7 V to 5.5 V; TJ = −40°C to +125°C for minimum/maximum specifications, and TA =
25°C for typical specifications, unless otherwise noted.
Table 2.
Parameter
INPUT VOLTAGE RANGE
THERMAL SHUTDOWN
Threshold
Hysteresis
START-UP TIME 1
BUCK1, LDO1, LDO2
BUCK2
EN1, EN2, EN3, EN4, MODE INPUTS
Input Logic High
Input Logic Low
Input Leakage Current
INPUT CURRENT
All Channels Enabled
All Channels Disabled
VIN1 UNDERVOLTAGE LOCKOUT
High UVLO Input Voltage Rising
High UVLO Input Voltage Falling
Low UVLO Input Voltage Rising
Low UVLO Input Voltage Falling
1
Symbol
VAVIN, VIN1, VIN2
Test Conditions/Comments
TSSD
TSSD-HYS
TJ rising
Min
2.3
tSTART1
tSTART2
VIH
VIL
VI-LEAKAGE
ISTBY-NOSW
ISHUTDOWN
Typ
Max
5.5
150
20
°C
°C
250
300
µs
µs
1.1
No load, no buck switching
TJ = −40°C to +85°C
UVLOVIN1RISE
UVLOVIN1FALL
UVLOVIN1RISE
UVLOVIN1FALL
0.05
0.4
1
V
V
µA
108
0.3
175
1
µA
µA
3.9
V
V
V
V
3.1
2.275
1.95
Unit
V
Start-up time is defined as the time from EN1 = EN2 = EN3 = EN4 from 0 V to VAVIN to VOUT1, VOUT2, VOUT3, and VOUT4 reaching 90% of their nominal level. Start-up
times are shorter for individual channels if another channel is already enabled. See the Typical Performance Characteristics section for more information.
Rev. D | Page 3 of 28
ADP5037
Data Sheet
BUCK1 AND BUCK2 SPECIFICATIONS
VAVIN = VIN1 = VIN2 = 2.3 V to 5.5 V; TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications,
unless otherwise noted. 1
Table 3.
Parameter
OUTPUT CHARACTERISTICS
Output Voltage Accuracy
Line Regulation
Load Regulation
VOLTAGE FEEDBACK
OPERATING SUPPLY CURRENT
BUCK1 Only
Test Conditions/Comments
Min
ΔVOUT1/VOUT1,
ΔVOUT2/VOUT2
(∆VOUT1/VOUT1)/∆VIN1,
(∆VOUT2/VOUT2)/∆VIN2
(∆VOUT1/VOUT1)/∆IOUT1,
(∆VOUT2/VOUT2)/∆IOUT2
VFB1, VFB2
PWM mode; ILOAD1 = ILOAD2 = 0 mA
−1.8
IIN
BUCK2 Only
IIN
BUCK1 and BUCK2
IIN
PSM CURRENT THRESHOLD
SW CHARACTERISTICS
SW On Resistance
Current Limit
ACTIVE PULL-DOWN
OSCILLATOR FREQUENCY
1
Symbol
IPSM
RNFET
RPFET
RNFET
RPFET
ILIMIT1, ILIMIT2
RPDWN-B
fSW
Typ
Max
Unit
+1.8
%
PWM mode
−0.05
%/V
ILOAD = 0 mA to 800 mA, PWM mode
−0.1
%/A
Models with adjustable outputs
MODE = ground
ILOAD1 = 0 mA, device not switching, all other
channels disabled
ILOAD2 = 0 mA, device not switching, all other
channels disabled
ILOAD1 = ILOAD2 = 0 mA, device not switching,
LDO channels disabled
PSM to PWM operation
VIN1 = VIN2 = 3.6 V
VIN1 = VIN2 = 3.6 V
VIN1 = VIN2 = 5.5 V
VIN1 = VIN2 = 5.5 V
pFET switch peak current limit
Channel disabled
0.491
1200
2.5
0.5
0.509
V
44
μA
55
μA
67
μA
100
mA
155
205
137
162
1550
75
3.0
240
310
204
243
1900
3.5
mΩ
mΩ
mΩ
mΩ
mA
Ω
MHz
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC).
LDO1 AND LDO2 SPECIFICATIONS
VIN3 = (VOUT3 + 0.5 V) or 1.7 V (whichever is greater) to 5.5 V, VIN4 = (VOUT4 + 0.5 V) or 1.7 V (whichever is greater) to 5.5 V; CIN = COUT =
1 µF; TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless otherwise noted. 1
Table 4.
Parameter
INPUT VOLTAGE RANGE
OPERATING SUPPLY CURRENT
Bias Current per LDO 2
Total System Input Current
Symbol
VIN3, VIN4
Test Conditions/Comments
IVIN3BIAS/IVIN4BIAS
IOUT3 = IOUT4 = 0 µA
IOUT3 = IOUT4 = 10 mA
IOUT3 = IOUT4 = 300 mA
Includes all current into AVIN, VIN1, VIN2, VIN3,
and VIN4
IOUT3 = IOUT4 = 0 µA, all other channels disabled
IOUT3 = IOUT4 = 0 µA, buck channels disabled
IIN
LDO1 or LDO2 Only
LDO1 and LDO2 Only
OUTPUT CHARACTERISTICS
Output Voltage Accuracy
Line Regulation
Load Regulation 3
ΔVOUT3/VOUT3,
ΔVOUT4/VOUT4
(∆VOUT3/VOUT3)/∆VIN3,
(∆VOUT4/VOUT4)/∆VIN4
(∆VOUT3/VOUT3)/∆IOUT3,
(∆VOUT4/VOUT4)/∆IOUT4
Min
1.7
Typ
Max
5.5
Unit
V
10
60
165
30
100
245
µA
µA
µA
53
74
µA
µA
100 µA < IOUT3 < 300 mA, 100 µA < IOUT4 < 300 mA
−1.8
+1.8
%
IOUT3 = IOUT4 = 1 mA
−0.03
+0.03
%/V
0.003
%/mA
IOUT3 = IOUT4 = 1 mA to 300 mA
Rev. D | Page 4 of 28
0.001
Data Sheet
Parameter
VOLTAGE FEEDBACK
DROPOUT VOLTAGE 4
CURRENT-LIMIT THRESHOLD 5
ACTIVE PULL-DOWN
OUTPUT NOISE
Regulator LDO1
Regulator LDO2
POWER SUPPLY REJECTION
RATIO
Regulator LDO1
ADP5037
Symbol
Test Conditions/Comments
Min
0.491
Channel disabled
Typ
0.5
50
75
100
180
600
600
10 Hz to 100 kHz, VIN3 = 5 V, VOUT3 = 2.8 V
10 Hz to 100 kHz, VIN4 = 5 V, VOUT4 = 1.2 V
100
60
µV rms
µV rms
10 kHz, VIN3 = 3.3 V, VOUT3 = 2.8 V, IOUT3 = 1 mA
100 kHz, VIN3 = 3.3 V, VOUT3 = 2.8 V, IOUT3 = 1 mA
1 MHz, VIN3 = 3.3 V, VOUT3 = 2.8 V, IOUT3 = 1 mA
10 kHz, VIN4 = 1.8 V, VOUT4 = 1.2 V, IOUT4 = 1 mA
100 kHz, VIN4 = 1.8 V, VOUT4 = 1.2 V, IOUT4 = 1 mA
1 MHz, VIN4 = 1.8 V, VOUT4 = 1.2 V, IOUT4 = 1 mA
60
62
63
54
57
64
dB
dB
dB
dB
dB
dB
VFB3, VFB4
VDROPOUT
ILIMIT3, ILIMIT4
RPDWN-L
NOISELDO1
NOISELDO2
PSRR
Regulator LDO2
VOUT3 = VOUT4 = 5.2 V, IOUT3 = IOUT4 = 300 mA
VOUT3 = VOUT4 = 3.3 V, IOUT3 = IOUT4 = 300 mA
VOUT3 = VOUT4 = 2.5 V, IOUT3 = IOUT4 = 300 mA
VOUT3 = VOUT4 = 1.8 V, IOUT3 = IOUT4 = 300 mA
335
Max
0.509
140
Unit
V
mV
mV
mV
mV
mA
Ω
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC).
This is the input current into VIN3/VIN4, which is not delivered to the output load.
3
Based on an endpoint calculation using 1 mA and 300 mA loads.
4
Dropout voltage is defined as the input-to-output voltage differential when the input voltage is set to the nominal output voltage. This applies only to output voltages
above 1.7 V.
5
Current-limit threshold is defined as the current at which the output voltage drops to 90% of the specified typical value. For example, the current limit for a 3.0 V
output voltage is defined as the current that causes the output voltage to drop to 90% of 3.0 V, or 2.7 V.
1
2
INPUT AND OUTPUT CAPACITOR, RECOMMENDED SPECIFICATIONS
TA = −40°C to +125°C, unless otherwise specified.
Table 5.
Parameter
NOMINAL INPUT AND OUTPUT CAPACITOR RATINGS
BUCK1, BUCK2 Input Capacitor Ratings
BUCK1, BUCK2 Output Capacitor Ratings
LDO 1 Input and Output Capacitor Ratings
CAPACITOR ESR
1
Symbol
Min
CMIN1, CMIN2
CMIN1, CMIN2
CMIN3, CMIN4
RESR
4.7
10
1.0
0.001
Typ
Max
Unit
40
40
µF
µF
µF
Ω
1
The minimum input and output capacitance should be greater than 0.70 µF over the full range of operating conditions. The full range of operating conditions in the
application must be considered during device selection to ensure that the minimum capacitance specification is met. X7R- and X5R-type capacitors are recommended;
Y5V and Z5U capacitors are not recommended for use because of their poor temperature and dc bias characteristics.
Rev. D | Page 5 of 28
ADP5037
Data Sheet
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 6.
Parameter
AVIN to AGND
VIN1, VIN2 to AVIN
PGND1, PGND2 to AGND
VIN3, VIN4, VOUT1, VOUT2, FB1, FB2,
FB3, FB4, EN1, EN2, EN3, EN4,
MODE to AGND
VOUT3 to AGND
VOUT4 to AGND
SW1 to PGND1
SW2 to PGND2
Storage Temperature Range
Operating Junction Temperature Range
Soldering Conditions
Rating
−0.3 V to +6 V
−0.3 V to +0.3 V
−0.3 V to +0.3 V
−0.3 V to (AVIN + 0.3 V)
−0.3 V to (VIN3 + 0.3 V)
−0.3 V to (VIN4 + 0.3 V)
−0.3 V to (VIN1 + 0.3 V)
−0.3 V to (VIN2 + 0.3 V)
−65°C to +150°C
−40°C to +125°C
JEDEC J-STD-020
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Table 7. Thermal Resistance
Package Type
24-Lead, 0.5 mm pitch LFCSP
ESD CAUTION
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
For detailed information on power dissipation, see the Power
Dissipation and Thermal Considerations section.
Rev. D | Page 6 of 28
θJA
35
θJC
3
Unit
°C/W
Data Sheet
ADP5037
24
23
22
21
20
19
VOUT4
VIN4
EN3
VIN3
VOUT3
FB3
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
2
3
4
5
6
PIN 1
INDICATOR
ADP5037
TOP VIEW
(Not to Scale)
18
17
16
15
14
13
AGND
AVIN
VIN1
SW1
PGND1
MODE
NOTES
1. NC = NOT INTERNALLY CONNECTED.
2. IT IS RECOMMENDED THAT THE EXPOSED PAD
BE SOLDERED TO THE GROUND PLANE.
09887-003
EN2
FB2
VOUT2
VOUT1
FB1
EN1
7
8
9
10
11
12
FB4
EN4
VIN2
SW2
PGND2
NC
Figure 2. Pin Configuration—View from the Top of the Die
Table 8. Pin Function Descriptions
Pin No.
1
Mnemonic
FB4
2
3
4
5
6
7
8
EN4
VIN2
SW2
PGND2
NC
EN2
FB2
9
10
11
VOUT2
VOUT1
FB1
12
13
14
15
16
17
18
19
EN1
MODE
PGND1
SW1
VIN1
AVIN
AGND
FB3
20
21
22
23
24
VOUT3
VIN3
EN3
VIN4
VOUT4
EPAD (EP)
Description
LDO2 Feedback Input. For device models with adjustable output voltage, connect this pin to the middle of the
LDO2 resistor divider. For device models with fixed output voltage, connect this pin to the top of the capacitor on
VOUT4.
LDO2 Enable Pin. High level turns on this regulator, and low level turns it off.
BUCK2 Input Supply (2.3 V to 5.5 V). Connect VIN2 to VIN1 and AVIN.
BUCK2 Switching Node.
Dedicated Power Ground for BUCK2.
No Connect. Leave this pin unconnected or connect to ground.
BUCK2 Enable Pin. High level turns on this regulator, and low level turns it off.
BUCK2 Feedback Input. For device models with adjustable output voltage, connect this pin to the middle of the
BUCK2 resistor divider. For device models with fixed output voltage, leave this pin unconnected.
BUCK2 Output Voltage Sensing Input. Connect VOUT2 to the top of the capacitor on VOUT2.
BUCK1 Output Voltage Sensing Input. Connect VOUT1 to the top of the capacitor on VOUT1.
BUCK1 Feedback Input. For device models with adjustable output voltage, connect this pin to the middle of the
BUCK1 resistor divider. For device models with fixed output voltage, leave this pin unconnected.
BUCK1 Enable Pin. High level turns on this regulator, and low level turns it off.
BUCK1/BUCK2 Operating Mode. MODE = high: forced PWM operation. MODE = low: auto PWM/PSM operation.
Dedicated Power Ground for BUCK1.
BUCK1 Switching Node.
BUCK1 Input Supply (2.3 V to 5.5 V). Connect VIN1 to VIN2 and AVIN.
Analog Input Supply (2.3 V to 5.5 V). Connect AVIN to VIN1 and VIN2.
Analog Ground.
LDO1 Feedback Input. For device models with adjustable output voltage, connect this pin to the middle of the
LDO1 resistor divider. For device models with fixed output voltage, connect this pin to the top of the capacitor on
VOUT3.
LDO1 Output Voltage.
LDO1 Input Supply (1.7 V to 5.5 V).
LDO1 Enable Pin. High level turns on this regulator, and low level turns it off.
LDO2 Input Supply (1.7 V to 5.5 V).
LDO2 Output Voltage.
Exposed Pad. It is recommended that the exposed pad be soldered to the ground plane.
Rev. D | Page 7 of 28
ADP5037
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
VIN1= VIN2 = VIN3= VIN4 = 3.6 V, TA = 25°C, unless otherwise noted.
3.310
140
–40°C
3.300
100
VOUT (V)
3.295
80
+25°C
3.290
60
3.285
40
3.280
20
3.275
0
2.3
2.8
3.3
3.8
4.3
4.8
5.3
3.270
INPUT VOLTAGE (V)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
IOUT (A)
Figure 3. System Quiescent Current vs. Input Voltage, VOUT1 = 3.3 V,
VOUT2 = 1.8 V, VOUT3 = 1.2 V, VOUT4 = 3.3 V, All Channels Unloaded
09887-100
+85°C
09887-039
QUIESCENT CURRENT (µA)
3.305
120
Figure 6. BUCK1 Load Regulation Across Temperature, VIN = 4.2 V,
VOUT1 = 3.3 V, Auto Mode
1.812
T
1.810
SW
–40°C
4
1.808
2
VOUT (V)
IOUT
VOUT
+25°C
1.806
1.804
1
1.802
+85°C
1.800
3
A CH3
1.798
09887-049
CH2 50.0mA Ω BW M 40.0µs
CH4 5.00V BW
T 11.20%
CH1 2.00V BW
CH3 5.00V BW
2.2V
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
IOUT (A)
09887-101
EN
Figure 7. BUCK2 Load Regulation Across Temperature, VIN = 3.6 V,
VOUT2 = 1.8 V, Auto Mode
Figure 4. BUCK1 Startup, VOUT1 = 1.8 V, IOUT1 = 5 mA
0.808
T
0.807
SW
4
0.806
IOUT
–40°C
VOUT (V)
2
VOUT
1
+25°C
0.805
+85°C
0.804
EN
0.803
BW
BW
CH2 50.0mA Ω BW M 40.0µs
BW
CH4 5.00V
T 11.20%
0.802
A CH3
2.2V
09887-048
CH1 2.00V
CH3 5.00V
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
IOUT (A)
Figure 8. BUCK1 Load Regulation Across Input Voltage, VIN = 3.6 V,
VOUT1 = 0.8 V, PWM Mode
Figure 5. BUCK2 Startup, VOUT2 = 3.3 V, IOUT2 = 10 mA
Rev. D | Page 8 of 28
09887-102
3
Data Sheet
ADP5037
100
100
90
90
80
80
VIN = 2.3V
VIN = 3.9V
VIN = 4.2V
VIN = 5.5V
50
40
VIN = 4.2V
60
50
40
VIN = 5.5V
30
30
20
20
10
10
0
1
10
100
1000
ILOAD (mA)
0
1
10
100
1000
ILOAD (mA)
Figure 9. BUCK1 Efficiency vs. Load Current, Across Input Voltage,
VOUT1 = 3.3 V, Auto Mode
09887-106
EFFICIENCY (%)
60
70
09887-103
EFFICIENCY (%)
70
VIN = 3.6V
Figure 12. BUCK2 Efficiency vs. Load Current, Across Input Voltage,
VOUT2 = 1.8 V, PWM Mode
100
100
VIN = 2.3V
90
90
80
80
VIN = 3.6V
70
70
50
VIN = 4.2V
40
VIN = 5.5V
30
40
30
20
10
10
0
10
VIN = 5.5V
50
20
1
VIN = 4.2V
60
100
1000
ILOAD (mA)
0
1
10
100
1000
ILOAD (mA)
Figure 10. BUCK1 Efficiency vs. Load Current, Across Input Voltage,
VOUT1 = 3.3 V, PWM Mode
09887-107
60
EFFICIENCY (%)
VIN = 3.6V
09887-104
EFFICIENCY (%)
VIN = 2.3V
Figure 13. BUCK1 Efficiency vs. Load Current, Across Input Voltage,
VOUT1 = 0.8 V, Auto Mode
100
100
VIN = 2.3V
90
90
80
80
VIN = 4.2V
VIN = 3.6V
70
60
50
40
50
20
20
10
10
10
100
1000
ILOAD (mA)
09887-105
30
1
Figure 11. BUCK2 Efficiency vs. Load Current, Across Input Voltage,
VOUT2 = 1.8 V, Auto Mode
VIN = 4.2V
40
30
0
VIN = 3.6V
60
VIN = 5.5V
0
1
10
100
1000
ILOAD (mA)
Figure 14. BUCK1 Efficiency vs. Load Current, Across Input Voltage,
VOUT1 = 0.8 V, PWM Mode
Rev. D | Page 9 of 28
09887-108
EFFICIENCY (%)
70
EFFICIENCY (%)
VIN = 2.3V
VIN = 5.5V
ADP5037
Data Sheet
3.3
100
+25°C
–40°C
90
3.2
+25°C
+85°C
80
3.1
–40°C
FREQUENCY (MHz)
EFFICIENCY (%)
70
60
50
40
30
3.0
+85°C
2.9
2.8
2.7
20
2.6
10
1
IOUT (A)
2.5
0
0.2
0.4
0.6
0.8
1.0
09887-031
0.1
0.01
09887-028
0
0.001
1.2
IOUT (A)
Figure 15. BUCK1 Efficiency vs. Load Current, Across Temperature,
VIN = 3.9 V, VOUT1 = 3.3 V, Auto Mode
Figure 18. BUCK2 Switching Frequency vs. Output Current, Across
Temperature, VOUT2 = 1.8 V, PWM Mode
100
90
+25°C
T
+85°C
VOUT
80
1
EFFICIENCY (%)
70
–40°C
ISW
60
50
2
40
SW
30
20
10
0.1
1
IOUT (A)
Figure 16. BUCK2 Efficiency vs. Load Current, Across Temperature,
VOUT2 = 1.8 V, Auto Mode
CH2 500mA Ω
CH4 2.00V
CH1 50.0mV
M 4.00µs
A CH2
240mA
T 28.40%
09887-051
4
0.01
09887-030
0
0.001
Figure 19. Typical Waveforms, VOUT1 = 3.3 V, IOUT1 = 30 mA, Auto Mode
100
T
+25°C
90
VOUT
80
1
EFFICIENCY (%)
70
+85°C
–40°C
60
ISW
50
2
40
30
SW
20
10
0.1
1
IOUT (A)
Figure 17. BUCK1 Efficiency vs. Load Current, Across Temperature
VOUT1 = 0.8 V, Auto Mode
CH1 50.0mV BW CH2 500mA Ω
CH4 2.00V BW
M 4.00µs
T 28.40%
A CH2
220mA
09887-050
0.01
09887-029
4
0
0.001
Figure 20. Typical Waveforms, VOUT2 = 1.8 V, IOUT2 = 30 mA, Auto Mode
Rev. D | Page 10 of 28
Data Sheet
ADP5037
T
T
VOUT
1
VIN
ISW
VOUT
2
1
SW
SW
4
3
B
W
CH2 500mA Ω
CH4 2.00V BW
M 400ns
A CH2
220mA
T 28.40%
CH1 50.0mV BW
M 1.00ms
CH3 1.00V BW
CH4 2.00V BW
T 30.40%
09887-053
CH1 50mV
Figure 21. Typical Waveforms, VOUT1 = 3.3 V, IOUT1 = 30 mA, PWM Mode
A CH3
4.80V
09887-041
4
Figure 24. BUCK2 Response to Line Transient, VIN2 = 4.5 V to 5.0 V,
VOUT2 = 1.8 V, PWM Mode
T
T
SW
VOUT
1
4
ISW
VOUT
2
1
SW
IOUT
B
W
CH2 500mA Ω
CH4 2.00V BW
M 400ns
A CH2
220mA
T 28.40%
09887-052
CH1 50mV
CH1 50.0mV
Figure 22. Typical Waveforms, VOUT2 = 1.8 V, IOUT2 = 30 mA, PWM Mode
B
W
CH2 50.0mA Ω BW M 20.0µs A CH2
CH4 5.00V BW
T 60.000µs
356mA
09887-044
2
4
Figure 25. BUCK1 Response to Load Transient, IOUT1 from 1 mA to 50 mA,
VOUT1 = 3.3 V, Auto Mode
T
T
SW
4
VIN
VOUT
VOUT
1
1
SW
IOUT
3
A CH3
4.80V
CH1 50.0mV
B
W CH2 50.0mA Ω W M 20.0µs A CH2
CH4 5.00V BW
B
T 22.20%
Figure 23. BUCK1 Response to Line Transient, Input Voltage from 4.5 V to
5.0 V, VOUT1 = 3.3 V, PWM Mode
379mA
09887-043
M 1.00ms
CH1 50.0mV BW
CH4 2.00V BW
CH3 1.00V BW
T 30.40%
09887-040
2
Figure 26. BUCK2 Response to Load Transient, IOUT2 from 1 mA to 50 mA,
VOUT2 = 1.8 V, Auto Mode
Rev. D | Page 11 of 28
ADP5037
Data Sheet
T
SW
EN
4
2
VOUT
1
VOUT
3
IOUT
IIN
2
B
W CH2 200mA Ω W M 20.0µs
CH4 5.00V BW
A CH2
408mA
T 20.40%
CH1 100mA
CH3 1.00V
CH2 5.0V
M40.0µs 2.5GS/s
T
159.4µs
A CH2
09887-109
B
CH1 50.0mV
09887-045
1
4.20V
Figure 30. LDO Startup, VOUT3 = 1.8 V
Figure 27. BUCK1 Response to Load Transient, IOUT1 from 20 mA to 180 mA,
VOUT1 = 3.3 V, Auto Mode
3.304
T
3.303
SW
3.302
4
3.301
VOUT (V)
VOUT
1
VIN = 5.5V
3.300
VIN = 4.2V
3.299
3.298
VIN = 3.8V
3.297
IOUT
3.296
3.295
2
W
CH2 200mA Ω BW M 20.0µs A CH2
CH4 5.00V BW
T 19.20%
88.0mA
0
09887-046
B
0.1
0.2
09887-110
3.294
CH1 100mV
0.3
IOUT (A)
Figure 31. LDO Load Regulation Across Input Voltage, VOUT3 = 3.3 V
Figure 28. BUCK2 Response to Load Transient, IOUT2 from 20 mA to 180 mA,
VOUT2 = 1.8 V, Auto Mode
400
T
350
VOUT2
300
2
+125°C
RDSON (mΩ)
SW1
3
VOUT1
250
+25°C
200
150
–40°C
1
100
SW2
50
B
W
B
W
CH2 5.00V BW
CH4 5.00V BW
M 400ns
T 50.00%
A CH4
1.90V
0
2.3
09887-060
CH1 5.00V
CH3 5.00V
2.8
3.3
3.8
4.3
4.8
5.3
INPUT VOLTAGE (V)
Figure 29. VOUT and SW Waveforms for BUCK1 and BUCK2 in PWM Mode
Showing Out-of-Phase Operation
Rev. D | Page 12 of 28
Figure 32. NMOS RDSON vs. Input Voltage Across Temperature
09887-037
4
Data Sheet
ADP5037
250
50
45
200
40
+125°C
GROUND CURRENT (µA)
RDSON (mΩ)
+25°C
150
–40°C
100
35
30
25
20
15
50
10
3.8
3.3
4.3
4.8
0
09887-038
2.8
5.3
INPUT VOLTAGE (V)
0
0.10
0.05
0.15
0.20
09887-036
5
0
2.3
0.25
LOAD CURRENT (A)
Figure 33. PMOS RDSON vs. Input Voltage Across Temperature
Figure 36. LDO Ground Current vs. Output Load, VIN3 = 3.3 V, VOUT3 = 2.8 V
1.802
T
1.801
–40°C
1.800
IOUT
VOUT (V)
1.799
2
1.798
1.797
+25°C
1.796
1
VOUT
1.795
1.794
+85°C
0
0.1
0.2
0.3
IOUT (A)
Figure 34. LDO Load Regulation Across Temperature, VIN3 = 3.6 V, VOUT3 = 1.8 V
3.0
2.5
VOUT (V)
2.0
IOUT = 10mA
CH1 100mV BW
09887-111
1.792
CH2 100mA Ω BW M 40.0µs A CH2
52.0mA
T 19.20%
09887-047
1.793
Figure 37. LDO Response to Load Transient, IOUT3 from 1 mA to 80 mA,
VOUT3 = 2.8 V
IOUT = 100µA
T
IOUT = 1mA
IOUT = 100mA
IOUT = 150mA
IOUT = 300mA
VIN
1.5
VOUT
2
1
1.0
0.5
VIN (V)
Figure 35. LDO Line Regulation Across Output Load, VOUT3 = 2.8 V
CH1 20.0mV
CH3 1.00V
M 100µs
T 28.40%
A CH3
4.80V
09887-042
0
2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4
09887-034
3
Figure 38. LDO Response to Line Transient, Input Voltage from 4.5 V to 5 V,
VOUT3 = 2.8 V
Rev. D | Page 13 of 28
ADP5037
Data Sheet
0
60
VIN = 5V
55
–20
VIN = 3.3V
–40
PSRR (dB)
45
40
–60
–80
35
–100
30
0.01
0.1
1
10
–120
10
09887-055
25
0.001
100
ILOAD (mA)
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
Figure 42. LDO PSRR Across Output Load, VIN3 = 3.3 V, VOUT3 = 3.0 V
Figure 39. LDO Output Noise vs. Load Current, Across Input Voltage,
VOUT3 = 2.8 V
0
65
VIN = 5V
60
–20
VIN = 3.3V
55
100µA
1mA
10mA
50mA
100mA
150mA
–40
50
PSRR (dB)
RMS NOISE (µV)
100µA
1mA
10mA
50mA
100mA
150mA
09887-058
RMS NOISE (µV)
50
45
–60
40
–80
35
–100
0.01
0.1
1
10
–120
10
09887-056
100
ILOAD (mA)
100µA
1mA
10mA
50mA
100mA
150mA
–10
–20
–30
PSRR (dB)
–40
–50
–60
10M
–60
–80
–80
–90
–90
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
100µA
1mA
10mA
50mA
100mA
150mA
–50
–70
–100
10
1M
–40
–70
09887-057
PSRR (dB)
–30
10k
100k
FREQUENCY (Hz)
0
0
–20
1k
Figure 43. LDO PSRR Across Output Load, VIN3 = 5.0 V, VOUT3 = 2.8 V
Figure 40. LDO Output Noise vs. Load Current, Across Input Voltage,
VOUT3 = 3.0 V
–10
100
–100
10
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
Figure 44. LDO PSRR Across Output Load, VIN3 = 5.0 V, VOUT3 = 3.0 V
Figure 41. LDO PSRR Across Output Load, VIN3 = 3.3 V, VOUT3 = 2.8 V
Rev. D | Page 14 of 28
09887-061
25
0.001
09887-059
30
Data Sheet
ADP5037
THEORY OF OPERATION
VOUT1 FB1 FB2 VOUT2
GM ERROR
AMP
AVIN
ENBK1
75Ω
75Ω
ENBK2
GM ERROR
AMP
PWM
COMP
PWM
COMP
VIN1
SOFT START
SOFT START
PSM
COMP
PSM
COMP
VIN2
ILIMIT
ILIMIT
LOW
CURRENT
PWM/
PSM
CONTROL
BUCK2
PWM/
PSM
CONTROL
BUCK1
LOW
CURRENT
SW2
SW1
OSCILLATOR
DRIVER
AND
ANTISHOOT
THROUGH
DRIVER
AND
OP
ANTISHOOT
MODE THROUGH
SYSTEM
UNDERVOLTAGE
LOCKOUT
SEL
THERMAL
SHUTDOWN
PGND1
Y
B
PGND2
MODE2
ENLDO2
A
600Ω
MODE
EN2
EN3
EN4
ENBK1
ENABLE
AND
MODE
CONTROL
ENBK2
LDO
UNDERVOLTAGE
LOCKOUT
ENLDO1
ENLDO2
LDO
UNDERVOLTAGE
LOCKOUT
R1
AVIN
R3
LDO
CONTROL
AVIN
R2
ADP5037
VIN3
AGND
600Ω
FB3 VOUT3 VIN4
LDO
CONTROL
ENLDO1
R4
FB4
VOUT4
09887-005
EN1
Figure 45. Functional Block Diagram
POWER MANAGEMENT UNIT
The ADP5037 is a micropower management units (micro PMU)
combining two step-down (buck) dc-to-dc convertors and
two low dropout linear regulators (LDOs). The high switching
frequency and tiny 24-lead LFCSP package allow for a small
power management solution.
To combine these high performance regulators into the micro
PMU, there is a system controller allowing them to operate
together.
The buck regulators can operate in forced PWM mode if the
MODE pin is at a logic high level. In forced PWM mode, the
buck switching frequency is always constant and does not
change with the load current. If the MODE pin is at logic low
level, the switching regulators operate in auto PWM/PSM
mode. In this mode, the regulators operate at fixed PWM
frequency when the load current is above the PSM current
threshold. When the load current falls below the PSM current
threshold, the regulator in question enters PSM, where the
switching occurs in bursts. The burst repetition rate is a
function of the current load and the output capacitor value.
This operating mode reduces the switching and quiescent current
losses. The auto PWM/PSM mode transition is controlled
independently for each buck regulator. The two bucks operate
synchronized to each other.
The ADP5037 has individual enable pins (EN1 to EN4) controlling the activation of each regulator. The regulators are activated
by a logic level high applied to the respective EN pin. EN1 controls
BUCK1, EN2 controls BUCK2, EN3 controls LDO1, and EN4
controls LDO2.
Regulator output voltages are set through external resistor
dividers or can be optionally factory programmed to default
values (see the Ordering Guide section).
When a regulator is turned on, the output voltage ramp rate is
controlled though a soft start circuit to avoid a large inrush
current due to the charging of the output capacitors.
Rev. D | Page 15 of 28
ADP5037
Data Sheet
Thermal Protection
In the event that the junction temperature rises above 150°C,
the thermal shutdown circuit turns off all the regulators. Extreme
junction temperatures can be the result of high current operation,
poor circuit board design, or high ambient temperature.
A 20°C hysteresis is included so that when thermal shutdown
occurs, the regulators do not return to operation until the on-chip
temperature drops below 130°C. When coming out of thermal
shutdown, all regulators restart with soft start control.
Undervoltage Lockout
To protect against battery discharge, undervoltage lockout
(UVLO) circuitry is integrated into the system. If the input
voltage on AVIN drops below a typical 2.15 V UVLO threshold,
all channels shut down. In the buck channels, both the power
switch and the synchronous rectifier turn off. When the voltage
on AVIN rises above the UVLO threshold, the part is enabled
once more.
Alternatively, the user can select device models with a UVLO
set at a higher level, suitable for 5 V supply applications. For
these models, the device reaches the turn-off threshold when
the input supply drops to 3.65 V typical.
In case of a thermal or UVLO event, the active pull-downs (if
factory enabled) are enabled to discharge the output capacitors
quickly. The pull-down resistors remain engaged until the thermal
fault event is no longer present, or the input supply voltage falls
below the VPOR voltage level. The typical value of VPOR is approximately 1 V.
Enable/Shutdown
The ADP5037 has an individual control pin for each regulator.
A logic level high applied to the ENx pin activates a regulator,
whereas a logic level low turns off a regulator.
Figure 46 shows the regulator activation timings for the ADP5037
when all enable pins are connected to AVIN. Also shown is the
active pull-down activation.
VUVLO
AVIN
VPOR
VOUT1
VOUT3
VOUT4
VOUT2
30µs
(MIN)
30µs
(MIN)
50µs (MIN)
50µs (MIN)
BUCK1,
LDO1,
LDO2
PULL-DOWNS
09887-006
BUCK2
PULL-DOWN
Figure 46. Regulator Sequencing on the ADP5037 (EN1 = EN2 = EN3 = EN4 = VAVIN)
Rev. D | Page 16 of 28
Data Sheet
ADP5037
BUCK1 AND BUCK2
The buck uses a fixed frequency and high speed current mode
architecture. The buck operates with an input voltage of 2.3 V
to 5.5 V.
The buck output voltage is set through external resistor dividers,
shown in Figure 47 for BUCK1. The output voltage can optionally
be factory programmed to default values as indicated in the
Ordering Guide section. In this event, R1 and R2 are not needed,
and FB1 can be left unconnected. In all cases, VOUT1 must be
connected to the output capacitor. FB1 is 0.5 V.
VOUT1
VIN1
SW1
L1
1µH
VOUT1
BUCK
PGND1
R1
C5
10µF
R1
VOUT1 = VFB1
+1
R2
The ADP5037 has a dedicated MODE pin controlling the PSM
and PWM operation. A high logic level applied to the MODE
pin forces both bucks to operate in PWM mode. A logic level
low sets the bucks to operate in auto PSM/PWM.
PSM Current Threshold
The PSM current threshold is set to100 mA. The bucks employ
a scheme that enables this current to remain accurately controlled,
independent of input and output voltage levels. This scheme
also ensures that there is very little hysteresis between the PSM
current threshold for entry to and exit from the PSM. The PSM
current threshold is optimized for excellent efficiency over all
load currents.
Oscillator/Phasing of Inductor Switching
R2
The ADP5037 ensures that both bucks operate at the same
switching frequency when both bucks are in PWM mode.
09887-008
FB1
This process is repeated while the load current is below the PSM
current threshold.
Figure 47. BUCK1 External Output Voltage Setting
Control Scheme
The bucks operate with a fixed frequency, current mode PWM
control architecture at medium to high loads for high efficiency
but shift to a power save mode (PSM) control scheme at light
loads to lower the regulation power losses. When operating in
fixed frequency PWM mode, the duty cycle of the integrated
switches is adjusted and regulates the output voltage. When
operating in PSM at light loads, the output voltage is controlled
in a hysteretic manner, with higher output voltage ripple. During
part of this time, the converter is able to stop switching and
enters an idle mode, which improves conversion efficiency.
PWM Mode
In PWM mode, the bucks operate at a fixed frequency of 3 MHz
set by an internal oscillator. At the start of each oscillator cycle,
the pFET switch is turned on, sending a positive voltage across
the inductor. Current in the inductor increases until the current
sense signal crosses the peak inductor current threshold that
turns off the pFET switch and turns on the nFET synchronous
rectifier. This sends a negative voltage across the inductor,
causing the inductor current to decrease. The synchronous
rectifier stays on for the rest of the cycle. The buck regulates the
output voltage by adjusting the peak inductor current threshold.
Power Save Mode (PSM)
The bucks smoothly transition to PSM operation when the load
current decreases below the PSM current threshold. When either of
the bucks enters PSM, an offset is induced in the PWM regulation
level, which makes the output voltage rise. When the output voltage
reaches a level approximately 1.5% above the PWM regulation
level, PWM operation is turned off. At this point, both power
switches are off, and the buck enters an idle mode. The output
capacitor discharges until the output voltage falls to the PWM
regulation voltage, at which point the device drives the inductor
to make the output voltage rise again to the upper threshold.
Additionally, the ADP5037 ensures that when both bucks are in
PWM mode, they operate out of phase, whereby the BUCK2 pFET
starts conducting exactly half a clock period after the BUCK1
pFET starts conducting.
Short-Circuit Protection
The bucks include frequency foldback to prevent output current
runaway on a hard short. When the voltage at the feedback pin falls
below half the target output voltage, indicating the possibility of
a hard short at the output, the switching frequency is reduced to
half the internal oscillator frequency. The reduction in the
switching frequency allows more time for the inductor to
discharge, preventing a runaway of output current.
Soft Start
The bucks have an internal soft start function that ramps the output
voltage in a controlled manner upon startup, thereby limiting
the inrush current. This prevents possible input voltage drops
when a battery or a high impedance power source is connected
to the input of the converter.
Current Limit
Each buck has protection circuitry to limit the amount of
positive current flowing through the pFET switch and the
amount of negative current flowing through the synchronous
rectifier. The positive current limit on the power switch limits
the amount of current that can flow from the input to the
output. The negative current limit prevents the inductor
current from reversing direction and flowing out of the load.
Rev. D | Page 17 of 28
ADP5037
Data Sheet
With a drop in input voltage, or with an increase in load current,
the buck may reach a limit where, even with the pFET switch
on 100% of the time, the output voltage drops below the desired
output voltage. At this limit, the buck transitions to a mode where
the pFET switch stays on 100% of the time. When the input
conditions change again and the required duty cycle falls, the
buck immediately restarts PWM regulation without allowing
overshoot on the output voltage.
Active Pull-Downs
Each LDO operates with an input voltage of 1.7 V to 5.5 V. The
wide operating range makes these LDOs suitable for cascading
configurations where the LDO supply voltage is provided from
one of the buck regulators.
Each LDO output voltage is set through external resistor dividers
as shown in Figure 48 for LDO1. The output voltage can optionally
be factory programmed to default values as indicated in the
Ordering Guide section. In this event, Ra and Rb are not needed,
and FB3 must be connected to the top of the capacitor on
VOUT3. FB3 is 0.5 V.
All regulators have optional, factory programmable, active pulldown resistors discharging the respective output capacitors
when the regulators are disabled. The pull-down resistors are
connected between VOUTx and AGND. Active pull-downs are
disabled when the regulators are turned on. The typical value of
the pull-down resistor is 600 Ω for the LDOs and 75 Ω for the
bucks. Figure 46 shows the activation timings for the active
pull-downs during regulator activation and deactivation.
VOUT3
VIN3
LDO1
FB3
VOUT3
Ra
C7
1µF
Rb
VOUT3 = VFB3
LDO1 AND LDO2
Ra
+1
Rb
09887-009
100% Duty Operation
Figure 48. LDO1 External Output Voltage Setting
The ADP5037 contains two LDOs with low quiescent current
and low dropout voltage, and provides up to 300 mA of output
current. Drawing a low 10 μA quiescent current (typical) at no load
makes the LDO ideal for battery-operated portable equipment.
The LDOs also provide high power supply rejection ratio (PSRR),
low output noise, and excellent line and load transient response
with only a small 1 µF ceramic input and output capacitor.
LDO1 is optimized to supply analog circuits because it offers
better noise performance compared to LDO2. LDO1 should be
used in applications where noise performance is critical.
Rev. D | Page 18 of 28
Data Sheet
ADP5037
APPLICATIONS INFORMATION
BUCK EXTERNAL COMPONENT SELECTION
Trade-offs between performance parameters such as efficiency
and transient response can be made by varying the choice of
external components in the applications circuit, as shown in
Figure 1.
Feedback Resistors
For the adjustable model, referring to Figure 47, the total
combined resistance for R1 and R2 is not to exceed 400 kΩ.
Inductor
The high switching frequency of the ADP5037 bucks allows for
the selection of small chip inductors. For best performance, use
inductor values between 0.7 μH and 3 μH. Suggested inductors
are shown in Table 9.
The peak-to-peak inductor current ripple is calculated using
the following equation:
I RIPPLE =
VOUT × (VIN − VOUT )
VIN × f SW × L
The worst-case capacitance accounting for capacitor variation
over temperature, component tolerance, and voltage is calculated
using the following equation:
CEFF = COUT × (1 − TEMPCO) × (1 − TOL)
where:
CEFF is the effective capacitance at the operating voltage.
TEMPCO is the worst-case capacitor temperature coefficient.
TOL is the worst-case component tolerance.
In this example, the worst-case temperature coefficient
(TEMPCO) over −40°C to +85°C is assumed to be 15% for an
X5R dielectric. The tolerance of the capacitor (TOL) is assumed
to be 10%, and COUT is 9.2 μF at 1.8 V, as shown in Figure 49.
where:
fSW is the switching frequency.
L is the inductor value.
The minimum dc current rating of the inductor must be greater
than the inductor peak current. The inductor peak current is
calculated using the following equation:
I PEAK = I LOAD( MAX ) +
Ceramic capacitors are manufactured with a variety of dielectrics,
each with a different behavior over temperature and applied
voltage. Capacitors must have a dielectric adequate to ensure
the minimum capacitance over the necessary temperature range
and dc bias conditions. X5R or X7R dielectrics with a voltage
rating of 6.3 V or 10 V are recommended for best performance.
Y5V and Z5U dielectrics are not recommended for use with any
dc-to-dc converter because of their poor temperature and dc
bias characteristics.
I RIPPLE
2
Substituting these values in the equation yields
CEFF = 9.2 μF × (1 − 0.15) × (1 − 0.1) = 7.0 μF
To guarantee the performance of the bucks, it is imperative
that the effects of dc bias, temperature, and tolerances on the
behavior of the capacitors be evaluated for each application.
12
Inductor conduction losses are caused by the flow of current
through the inductor, which has an associated internal dc
resistance (DCR). Larger sized inductors have smaller DCR,
which may decrease inductor conduction losses. Inductor core
losses are related to the magnetic permeability of the core material.
Because the bucks are high switching frequency dc-to-dc
converters, shielded ferrite core material is recommended for
its low core losses and low EMI.
CAPACITANCE (µF)
10
8
6
4
Output Capacitor
Higher output capacitor values reduce the output voltage ripple
and improve load transient response. When choosing this value,
it is also important to account for the loss of capacitance due to
output voltage dc bias.
0
0
1
2
3
4
5
DC BIAS VOLTAGE (V)
6
09887-010
2
Figure 49. Capacitance vs. Voltage Characteristic
Table 9. Suggested 1.0 μH Inductors
Vendor
Murata
Murata
Taiyo Yuden
Coilcraft
Coilcraft
Toko
Model
LQM2MPN1R0NG0B
LQM18FN1R0M00B
CBC3225T1R0MR
XFL4020-102ME
XPL2010-102ML
MDT2520-CN
Dimensions (mm)
2.0 × 1.6 × 0.9
3.2 × 2.5 × 1.5
3.2 × 2.5 × 2.5
4.0 × 4.0 × 2.1
1.9 × 2.0 × 1.0
2.5 × 2.0 × 1.2
Rev. D | Page 19 of 28
ISAT (mA)
1400
2300
2000
5400
3750
1350
DCR (mΩ)
85
54
71
11
89
85
ADP5037
Data Sheet
To minimize supply noise, place the input capacitor as close as
possible to the VINx pin of the buck. As with the output capacitor,
a low ESR capacitor is recommended.
The peak-to-peak output voltage ripple for the selected output
capacitor and inductor values is calculated using the following
equation:
The effective capacitance needed for stability, which includes
temperature and dc bias effects, is a minimum of 3 µF and a
maximum of 10 µF. A list of suggested capacitors is shown in
Table 10 and Table 11.
V IN
I RIPPLE
≈
8 × f SW × C OUT (2π × f SW ) 2 × L × C OUT
Capacitors with lower effective series resistance (ESR) are
preferred to guarantee low output voltage ripple, as shown in
the following equation:
ESRCOUT ≤
Table 10. Suggested 10 μF Capacitors
VRIPPLE
I RIPPLE
Vendor
Murata
TDK
Panasonic
The effective capacitance needed for stability, which includes
temperature and dc bias effects, is a minimum of 7 µF and a
maximum of 40 µF.
Model
GRM188R60J106
C1608JB0J106K
ECJ1VB0J106M
Vendor
Murata
Taiyo Yuden
Panasonic
Vendor
Murata
TDK
Panasonic
Taiyo
Yuden
Higher value input capacitors help to reduce the input voltage
ripple and improve transient response. Maximum input
capacitor current is calculated using the following equation:
Type
X5R
X5R
X5R
Model
GRM188R60J475ME19D
JMK107BJ475
ECJ-0EB0J475M
Type
X5R
X5R
X5R
X5R
Model
GRM155B30J105K
C1005JB0J105KT
ECJ0EB0J105K
LMK105BJ105MV-F
VOUT (VIN − VOUT )
VIN
AVIN
2.3V TO
5.5V
HOUSEKEEPING
VOUT1
VIN1
SW1
C1
4.7µF
ON
OFF
BUCK1
EN1
EN1
FB1
PGND1
L1 1µH
MODE
SW2
BUCK2
EN2
ON
EN3
EN2
EN3
VIN3
1.7V TO
5.5V
C3
1µF
ON
PWM
PSM/PWM
FB2
PGND2
L2 1µH
R3
R4
VIN4
VOUT2 @
800mA
C6
10µF
VOUT3
LDO1
(ANALOG)
FB3
R5
R6
EN4
OFF
C4
1µF
C5
10µF
R2
MODE
VOUT2
C2
4.7µF
OFF
VOUT1 @
800mA
R1
MODE
VIN2
Voltage
Rating
(V)
6.3
6.3
6.3
Case
Size
0402
0402
0402
Voltage
Rating
(V)
6.3
6.3
6.3
Table 12. Suggested 1.0 μF Capacitors
Input Capacitor
CAVIN
0.1µF
Case
Size
0603
0603
0603
Table 11. Suggested 4.7 μF Capacitors
The buck regulators require 10 µF output capacitors to guarantee
stability and response to rapid load variations and to transition into
and out of the PWM/PSM modes. A list of suggested capacitors is
shown in Table 10. In certain applications where one or both buck
regulator powers a processor, the operating state is known
because it is controlled by software. In this condition, the
processor can drive the MODE pin according to the operating
state; consequently, it is possible to reduce the output capacitor
from 10 µF to 4.7 µF because the regulator does not expect a
large load variation when working in PSM mode (see Figure 50).
I CIN ≥ I LOAD ( MAX )
Type
X5R
X5R
X5R
VOUT3 @
300mA
C7
1µF
VOUT4
EN4
LDO2
(DIGITAL)
FB4
R7
R8
VOUT4 @
300mA
C8
1µF
ADP5037
AGND
Figure 50. Processor System Power Management with PSM/PWM Control
Rev. D | Page 20 of 28
09887-021
V RIPPLE =
Case
Size
0402
0402
0402
0402
Voltage
Rating (V)
6.3
6.3
6.3
10.0
Data Sheet
ADP5037
LDO EXTERNAL COMPONENT SELECTION
1.2
Feedback Resistors
The ADP5037 LDOs are designed for operation with small, spacesaving ceramic capacitors, but function with most commonly
used capacitors as long as care is taken with the ESR value. The
ESR of the output capacitor affects stability of the LDO control
loop. A minimum of 0.70 µF capacitance with an ESR of 1 Ω or
less is recommended to ensure that stability of the ADP5037.
Transient response to changes in load current is also affected by
output capacitance. Using a larger value of output capacitance
improves the transient response of the ADP5037 to large
changes in load current.
Input Bypass Capacitor
Connecting a 1 µF capacitor from VIN3 and VIN4 to ground
reduces the circuit sensitivity to printed circuit board (PCB)
layout, especially when long input traces or high source impedance
is encountered. If greater than 1 µF of output capacitance is
required, increase the input capacitor to match it.
Input and Output Capacitor Properties
0.8
0.6
0.4
0.2
0
0
1
2
3
4
DC BIAS VOLTAGE (V)
5
6
09887-012
Output Capacitor
CAPACITANCE (µF)
1.0
For the adjustable model, the maximum value of Rb is not to
exceed 200 kΩ (see Figure 48).
Figure 51. Capacitance vs. Voltage Characteristic
Use the following equation to determine the worst-case capacitance accounting for capacitor variation over temperature,
component tolerance, and voltage:
CEFF = CBIAS × (1 − TEMPCO) × (1 − TOL)
where:
CBIAS is the effective capacitance at the operating voltage.
TEMPCO is the worst-case capacitor temperature coefficient.
TOL is the worst-case component tolerance.
Use any good quality ceramic capacitors with the ADP5037 as
long as they meet the minimum capacitance and maximum ESR
requirements. Ceramic capacitors are manufactured with a variety
of dielectrics, each with a different behavior over temperature
and applied voltage. Capacitors must have a dielectric adequate to
ensure the minimum capacitance over the necessary temperature
range and dc bias conditions. X5R or X7R dielectrics with a voltage
rating of 6.3 V or 10 V are recommended for best performance.
Y5V and Z5U dielectrics are not recommended for use with any
LDO because of their poor temperature and dc bias characteristics.
In this example, the worst-case temperature coefficient (TEMPCO)
over −40°C to +85°C is assumed to be 15% for an X5R dielectric.
The tolerance of the capacitor (TOL) is assumed to be 10%, and
CBIAS is 0.85 μF at 1.8 V as shown in Figure 51.
Figure 51 depicts the capacitance vs. voltage bias characteristic
of a 0402 1 µF, 10 V, X5R capacitor. The voltage stability of a
capacitor is strongly influenced by the capacitor size and voltage
rating. In general, a capacitor in a larger package or with higher
voltage rating exhibits better stability. The temperature variation
of the X5R dielectric is about ±15% over the −40°C to +85°C
temperature range and is not a function of package or voltage
rating.
To guarantee the performance of the ADP5037, it is imperative
that the effects of dc bias, temperature, and tolerances on the
behavior of the capacitors be evaluated for each application.
Substituting these values into the following equation,
CEFF = 0.85 μF × (1 − 0.15) × (1 − 0.1) ≈ 0.65 μF
Therefore, the capacitor chosen in this example meets the
minimum capacitance requirement of the LDO over
temperature and tolerance at the chosen output voltage.
Rev. D | Page 21 of 28
ADP5037
Data Sheet
POWER DISSIPATION AND THERMAL CONSIDERATIONS
The ADP5037 is a highly efficient µPMU, and, in most cases, the
power dissipated in the device is not a concern. However, if the
device operates at high ambient temperatures and maximum
loading condition, the junction temperature can reach the
maximum allowable operating limit (125°C).
When the temperature exceeds 150°C, the ADP5037 turns off
all the regulators, allowing the device to cool down. When the
die temperature falls below 130°C, the ADP5037 resumes
normal operation.
This section provides guidelines to calculate the power dissipated
in the device and ensure that the ADP5037 operates below the
maximum allowable junction temperature.
The efficiency for each regulator on the ADP5037 is given by
P
η = OUT × 100%
PIN
(1)
where:
η is the efficiency.
PIN is the input power.
POUT is the output power.
BUCK REGULATOR POWER DISSIPATION
The power loss of the buck regulator is approximated by
PLOSS = PDBUCK + PL
(3)
where:
PDBUCK is the power dissipation on one of the ADP5037 buck
regulators.
PL is the inductor power losses.
The inductor losses are external to the device, and they do not
have any effect on the die temperature.
The inductor losses are estimated (without core losses) by
PL ≈ IOUT1(RMS)2 × DCRL
(4)
where:
DCRL is the inductor series resistance.
IOUT1(RMS) is the rms load current of the buck regulator.
I OUT 1( RMS ) = I OUT1 × 1 +
r
12
(5)
where r is the normalized inductor ripple current.
r = VOUT1 × (1 − D)/(IOUT1 × L × fSW)
Power loss is given by
PLOSS = PIN − POUT
(2a)
PLOSS = POUT (1− η)/η
(2b)
or
Power dissipation can be calculated in several ways. The most
intuitive and practical is to measure the power dissipated at the
input and all the outputs. Perform the measurements at the
worst-case conditions (voltages, currents, and temperature).
The difference between input and output power is dissipated in
the device and the inductor. Use Equation 4 to derive the power
lost in the inductor and, from this, use Equation 3 to calculate
the power dissipation in the ADP5037 buck converter.
A second method to estimate the power dissipation uses the
efficiency curves provided for the buck regulator, and the power
lost on each LDO can be calculated using Equation 12. When
the buck efficiency is known, use Equation 2b to derive the total
power lost in the buck regulator and inductor, use Equation 4 to
derive the power lost in the inductor, and then calculate the
power dissipation in the buck converter using Equation 3. Add
the power dissipated in the buck and in the two LDOs to find
the total dissipated power.
Note that the buck efficiency curves are typical values and may
not be provided for all possible combinations of VIN, VOUT, and
IOUT. To account for these variations, it is necessary to include a
safety margin when calculating the power dissipated in the buck.
(6)
where:
L is the inductance.
fSW is the switching frequency.
D is the duty cycle.
D = VOUT1/VIN1
(7)
The ADP5037 buck regulator power dissipation, PDBUCK, includes
the power switch conductive losses, the switch losses, and the
transition losses of each channel. There are other sources of
loss, but these are generally less significant at high output load
currents, where the thermal limit of the application is. Equation
8 captures the calculation that must be made to estimate the
power dissipation in the buck regulator.
PDBUCK = PCOND + PSW + PTRAN
(8)
The power switch conductive losses are due to the output current,
IOUT1, flowing through the P-MOSFET and the N-MOSFET
power switches that have internal resistance, RDSON-P and
RDSON-N. The amount of conductive power loss is found by
PCOND = [RDSON-P × D + RDSON-N × (1 − D)] × IOUT1(RMS)2
(9)
where RDSON-P is approximately 0.2 Ω, and RDSON-N is approximately 0.16 Ω at 25°C junction temperature and VIN1 = VIN2 =
3.6 V. At VIN1 = VIN2 = 2.3 V, these values change to 0.31 Ω and
0.21 Ω, respectively, and at VIN1 = VIN2 = 5.5 V, the values are
0.16 Ω and 0.14 Ω, respectively.
A third way to estimate the power dissipation is analytical and
involves modeling the losses in the buck circuit provided by
Equation 8 to Equation 11 and the losses in the LDO provided
by Equation 12.
Rev. D | Page 22 of 28
Data Sheet
ADP5037
Switching losses are associated with the current drawn by the
driver to turn on and turn off the power devices at the switching
frequency. The amount of switching power loss is given by
PSW = (CGATE-P + CGATE-N) × VIN12 × fSW
(10)
where:
CGATE-P is the P-MOSFET gate capacitance.
CGATE-N is the N-MOSFET gate capacitance.
The transition losses occur because the P-channel power
MOSFET cannot be turned on or off instantaneously, and the
SW node takes some time to slew from near ground to near
VOUT1 (and from VOUT1 to ground). The amount of transition
loss is calculated by
(11)
where tRISE and tFALL are the rise time and the fall time of the
switching node, SW. For the ADP5037, the rise and fall times of
SW are in the order of 5 ns.
If the preceding equations and parameters are used for estimating the converter efficiency, it must be noted that the equations
do not describe all of the converter losses, and the parameter
values given are typical numbers. The converter performance
also depends on the choice of passive components and board
layout; therefore, a sufficient safety margin should be included
in the estimate.
LDO Regulator Power Dissipation
The power loss of a LDO regulator is given by
PDLDO = [(VIN − VOUT) × ILOAD] + (VIN × IGND)
In cases where the board temperature, TA, is known, the thermal
resistance parameter, θJA, can be used to estimate the junction
temperature rise. TJ is calculated from TA and PD using the
formula
TJ = TA + (PD × θJA)
For the ADP5037, the total of (CGATE-P + CGATE-N) is
approximately 150 pF.
PTRAN = VIN1 × IOUT1 × (tRISE + tFALL) × fSW
JUNCTION TEMPERATURE
(12)
where:
ILOAD is the load current of the LDO regulator.
VIN and VOUT are input and output voltages of the LDO,
respectively.
IGND is the ground current of the LDO regulator.
The typical θJA value for the 24-lead, 4 mm × 4 mm LFCSP is
35°C/W (see Table 7). A very important factor to consider is
that θJA is based on a 4-layer 4 in × 3 in, 2.5 oz copper, as per
JEDEC standard, and real applications may use different sizes
and layers. It is important to maximize the copper used to remove
the heat from the device. Copper exposed to air dissipates heat
better than copper used in the inner layers. The exposed pad
should be connected to the ground plane with several vias.
If the case temperature can be measured, the junction
temperature is calculated by
TJ = TC + (PD × θJC)
(15)
where TC is the case temperature and θJC is the junction-to-case
thermal resistance provided in Table 7.
When designing an application for a particular ambient
temperature range, calculate the expected ADP5037 power
dissipation (PD) due to the losses of all channels by using the
Equation 8 to Equation 13. From this power calculation, the
junction temperature, TJ, can be estimated using Equation 14.
The reliable operation of the converter and the two LDO regulators
can be achieved only if the estimated die junction temperature of
the ADP5037 (Equation 14) is less than 125°C. Reliability and
mean time between failures (MTBF) are highly affected by increasing the junction temperature. Additional information about
product reliability can be found from the ADI Reliability Handbook,
which can be found at www.analog.com/reliability_handbook.
Power dissipation due to the ground current is small and it
can be ignored.
The total power dissipation in the ADP5037 simplifies to
PD = PDBUCK1 + PDBUCK2 + PDLDO1 + PDLDO2
(14)
(13)
Rev. D | Page 23 of 28
ADP5037
Data Sheet
PCB LAYOUT GUIDELINES
Poor layout can affect ADP5037 performance, causing electromagnetic interference (EMI) and electromagnetic compatibility
(EMC) problems, ground bounce, and voltage losses. Poor layout
can also affect regulation and stability. A good layout is
implemented using the following guidelines.
•
•
•
•
Place the inductor, input capacitor, and output capacitor
close to the IC using short tracks. These components carry
high switching frequencies, and large tracks act as antennas.
Route the output voltage path away from the inductor and
SW node to minimize noise and magnetic interference.
•
Maximize the size of ground metal on the component side
to help with thermal dissipation.
Use a ground plane with several vias connecting to the
component side ground to further reduce noise interference
on sensitive circuit nodes.
Connect VIN1, VIN2, and AVIN together close to the IC
using short tracks.
In addition, refer to the UG-271 User Guide.
Rev. D | Page 24 of 28
Data Sheet
ADP5037
TYPICAL APPLICATION SCHEMATICS
AVIN
CAVIN
0.1µF
2.3V TO
5.5V
HOUSEKEEPING
VOUT1
VIN1
SW1
C1
4.7µF
ON
OFF
BUCK1
EN1
L1 1µH
FB1
PGND1
EN1
MODE
PWM
MODE
MODE
SW2
C2
4.7µF
BUCK2
EN2
ON
EN3
EN2
EN3
VIN3
1.7V TO
5.5V
PSM/PWM
VOUT2
VIN2
OFF
FB2
L2 1µH
C6
10µF
PGND2
VOUT3
LDO1
(ANALOG)
VOUT3 @
300mA
FB3
C7
1µF
VOUT4
LDO2
(DIGITAL)
VIN4
C4
1µF
VOUT4 @
300mA
FB4
C8
1µF
09887-022
EN4
OFF
VOUT2 @
800mA
R3
C3
1µF
ON
VOUT1 @
800mA
C5
10µF
ADP5037
AGND
Figure 52. ADP5037 Fixed Output Voltages with Enable Pins
AVIN
CAVIN
0.1µF
VOUT1
VIN1
SW1
C1
4.7µF
ON
OFF
BUCK1
EN1
EN1
FB1
PGND1
L1 1µH
PWM
MODE
SW2
C2
4.7µF
BUCK2
EN2
EN3
EN2
EN3
VIN3
1.7V TO
5.5V
C3
1µF
ON
FB2
PGND2
L2 1µH
R3
R4
VIN4
VOUT2 @
800mA
C6
10µF
VOUT3
LDO1
(ANALOG)
FB3
R5
R6
EN4
OFF
C4
1µF
PSM/PWM
VOUT2
VIN2
ON
C5
10µF
R2
MODE
MODE
OFF
VOUT1 @
800mA
R1
VOUT3 @
300mA
C7
1µF
VOUT4
EN4
LDO2
(DIGITAL)
FB4
R7
R8
VOUT4 @
300mA
C8
1µF
ADP5037
AGND
Figure 53. ADP5037 Adjustable Output Voltages with Enable Pins
Rev. D | Page 25 of 28
09887-023
2.3V TO
5.5V
HOUSEKEEPING
ADP5037
Data Sheet
BILL OF MATERIALS
Table 13.
Reference
CAVIN
C3, C4, C7, C8
C1, C2
C5, C6
L1, L2
IC1
Value
0.1 µF, X5R, 6.3 V
1 µF, X5R, 6.3 V
4.7 µF, X5R, 6.3 V
10 µF, X5R, 6.3 V
1 µH, 0.18 Ω, 850 mA
1 µH, 0.085 Ω, 1400 mA
1 µH, 0.059 Ω, 900 mA
1 µH, 0.086 Ω, 1350 mA
Four-regulator micro PMU
Part Number
JMK105BJ104MV-F
LMK105BJ105MV-F
ECJ-0EB0J475M
JMK107BJ106MA-T
BRC1608T1R0M
LQM2MPN1R0NG0B
EPL2014-102ML
MDT2520-CN
ADP5037
Rev. D | Page 26 of 28
Vendor
Taiyo-Yuden
Taiyo-Yuden
Panasonic-ECG
Taiyo-Yuden
Taiyo-Yuden
Murata
Coilcraft
Toko
Analog Devices
Package or Dimension (mm)
0402
0402
0402
0603
0603
2.0 × 1.6 × 0.9
2.0 × 2.0 × 1.4
2.5 × 2.0 × 1.2
24-lead LFCSP
Data Sheet
ADP5037
OUTLINE DIMENSIONS
0.30
0.25
0.20
0.50
BSC
PIN 1
INDICATOR
24
19
18
1
EXPOSED
PAD
0.50
0.40
0.30
TOP VIEW
0.80
0.75
0.70
13
12
2.20
2.10 SQ
2.00
6
7
0.25 MIN
BOTTOM VIEW
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
0.05 MAX
0.02 NOM
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-220-WGGD-8.
06-11-2012-A
PIN 1
INDICATOR
4.10
4.00 SQ
3.90
Figure 54. 24-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
4 mm × 4 mm Body, Very Very Thin Quad
(CP-24-10)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
ADP5037ACPZ-R7
ADP5037ACPZ-1-R7
Temperature
Range
−40°C to +125°C
−40°C to +125°C
ADP5037ACPZ-2-R7
−40°C to +125°C
ADP5037ACPZ-3-R7
ADP5037CP-EVALZ
−40°C to +125°C
Output Voltage2
Adjustable
VOUT1 = 1.2 V,
VOUT2 = 3.3 V,
VOUT3 = 2.8 V,
VOUT4 = 1.8 V
VOUT1 = 1.0 V,
VOUT2 = 1.8 V,
VOUT3 = 3.3 V,
VOUT4 = 2.8 V
Adjustable
UVLO3
Low
Low
Active Pull-Down4
Enabled on Buck Channels
Enabled on Buck Channels
Package Description
24-Lead LFCSP_WQ
24-Lead LFCSP_WQ
Package
Option
CP-24-10
CP-24-10
Low
Enabled on All Channels
24-Lead LFCSP_WQ
CP-24-10
High
Enabled on All Channels
24-Lead LFCSP_WQ
Evaluation Board for
ADP5037ACPZ-R7
CP-24-10
1
Z = RoHS Compliant Part.
2
For additional options, contact a local sales or distribution representative. Additional options available are:
BUCK1 and BUCK2: 3.3 V, 3.0 V, 2.8 V, 2.5 V, 2.3 V, 2.0 V, 1.8 V, 1.6 V, 1.5 V, 1.4 V, 1.3 V, 1.2 V, 1.1 V, 1.0 V, 0.9 V, or adjustable.
LDO1 and LDO2: 3.3 V, 3.0 V, 2.8 V, 2.5 V, 2.25 V, 2 V, 1.8 V, 1.7 V, 1.6 V, 1.5 V, 1.2 V, 1.1 V, 1.0 V, 0.9 V, 0.8 V, or adjustable.
3
UVLO: low or high.
4
BUCK1, BUCK2, and both LDO1 and LDO2: active pull-down resistor is programmable to be either enabled or disabled.
Rev. D | Page 27 of 28
ADP5037
Data Sheet
NOTES
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D09887-0-5/13(D)
Rev. D | Page 28 of 28
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