High Efficiency Dual Output
Power Supply Controller
ADP3025
FEATURES
Wide input voltage range: 5.5 V to 25 V
High conversion efficiency > 96%
Integrated current sense—no external resistor required
Low shutdown current: 19 µA (typical)
Voltage mode PWM with input feed-forward for fast line
transient response
Dual synchronous buck controllers
Built-in gate drive boost circuit for driving external high-side
N-channel MOSFET
2 independently programmable output voltages:
Fixed 3.3 V or adjustable (800 mV to 6.0 V)
Fixed 5 V or adjustable (800 mV to 6.0 V)
Programmable PWM frequency
Integrated linear regulator controller
Extensive circuit protection functions
GENERAL DESCRIPTION
The ADP3025 is a highly efficient, dual synchronous buck
switching regulator controller optimized for converting a
battery or adapter input into the supply voltage required in
portable products and industrial systems. The oscillator
frequency can be programmed for 200 kHz or 300 kHz
operation, or can be synchronized to an external clock signal of
up to 350 kHz.
The ADP3025 provides accurate and reliable short-circuit
protection by using an internal current sense circuit that
reduces cost and increases overall efficiency. Other protection
features include programmable soft start, UVLO, and integrated
output undervoltage/overvoltage protection. The ADP3025
contains a linear regulator controller designed to drive an
external N-channel MOSFET. The linear regulator output is
adjustable and can be used to generate auxiliary supply voltages.
The ADP3025 is specified over the 0°C to 70°C commercial
temperature range and is available in a 38-lead TSSOP package.
APPLICATIONS
Portable instruments
General-purpose dc-to-dc converters
SIMPLIFIED FUNCTIONAL BLOCK DIAGRAM
V
IN
5.5V TO 25V
PFO
5V LINEAR
REGULATOR
REF
Q1
L1
5V
SWITCHING
CONTROLLER
3.3V
SWITCHING
CONTROLLER
3.3V
Q2
800mV
Q3
L2
5V
Q4
SS5
SS3
Q5
LINEAR
CONTROLLER
POWER-ON
RESET
PWRGD
2.5V
ADP3025
Figure 1.
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
© 2004 Analog Devices, Inc. All rights reserved.
02699-0-001
ADP3025
TABLE OF CONTENTS
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 11
Internal 5 V Supply (INTVCC) ................................................ 11
Reference (REF).......................................................................... 11
Boosted High-Side Gate Drive Supply (BST) ......................... 11
Synchronous Rectifier (DRVL) ................................................ 11
Oscillator Frequency and Synchronization (SYNC).............. 11
Shutdown SD............................................................................... 11
Soft Start and Power-Up Sequencing (SS) .............................. 11
Current Limiting (CLSET) ........................................................ 12
Output Undervoltage Protection.............................................. 12
Output Overvoltage and Reverse Voltage Protection............ 12
Power Good Output (PWRGD) ............................................... 12
Linear Regulator Controller...................................................... 12
Output Voltage Adjustment ...................................................... 13
Application Information ........................................................... 13
Input Voltage Range ................................................................... 13
Maximum Output Current and MOSFET Selection ............. 14
Nominal Inductor Value............................................................ 15
Inductor Selection ...................................................................... 15
C
IN
and C
OUT
Selection ............................................................... 16
Power MOSFET Selection......................................................... 16
Soft Start ...................................................................................... 17
Fixed or Adjustable Output Voltage......................................... 17
Efficiency Enhancement............................................................ 17
Transient Response Considerations......................................... 18
Feedback Loop Compensation................................................. 18
Compensation Loop Design and Test Method ...................... 19
Recommended Applications..................................................... 19
Layout Considerations............................................................... 19
Outline Dimensions ....................................................................... 21
Ordering Guide .......................................................................... 21
REVISION HISTORY
Revision A
4/04—Data Sheet changed from Rev. 0 to Rev. A
Change
Page
Changes to Features...................................................................... 1
Changes to Specifications ............................................................ 3
Changes to Figures 4 and 5.......................................................... 9
Changes to Theory of Operation section ................................ 11
Changes to Output Voltage Adjustment section .................... 13
Changes to Table 5...................................................................... 13
Changes to Table 6...................................................................... 15
Changes to Table 8...................................................................... 16
Changes to Table 9...................................................................... 17
1/04—Revision 0: Initial Version
Rev. A | Page 2 of 24
ADP3025
SPECIFICATIONS
1
Table 1. T
A
= 0°C to 70°C, V
IN
= 12 V, SS5 = SS3 = INTVCC, INTVCC Load = 0 mA, REF Load = 0 mA, SYNC = 0 V,
SD = 5 V, unless otherwise noted
Parameter
INTERNAL 5 V REGULATOR
Input Voltage Range
Output Voltage
Line Regulation
Total Variation
VIN Undervoltage Lockout
Threshold Voltage
Hysteresis
REFERENCE
Output Voltage
2
SUPPLY
Shutdown Current
Standby Current
Quiescent Current
Symbol
INTVCC
Conditions
Min
5.5
4.95
4.8
4.05
4.25
270
800
19
120
1.3
Typ
Max
25
5.15
5.2
4.5
Unit
V
V
mV/V
V
V
mV
mV
µA
µA
mA
V
UVLO
T
A
= 25°C
5.5 V ≤ VIN ≤ 25 V
Full VIN and temperature range
INTVCC falling
5.02
1.0
REF
I
Q
5.5 V ≤ VIN ≤ 25 V
5.5 V ≤ VIN ≤ 25 V, SD= 0 V
SS3 = SS5 = COMP2/SD2 = 0 V, SD = 5 V
No loads, SS3 = SS5 = COMP2/SD2 = 4 V,
FB5 = 810 mV, FB3 = 810 mV, FB2 = 810 mV,
ADJ/FX5 = ADJ/FX3 = 5 V
784
816
70
200
1.9
OSCILLATOR
Frequency
SYNC Input
Frequency Range
Input Low Voltage
3
Input High Voltage
3
Input Current
POWER GOOD
Output Voltage in Regulation
Output Voltage out of Regulation
PWRGD Trip Threshold
PWRGD Hysteresis
CPOR Pull-Up Current
ERROR AMPLIFIER
DC Gain
3
Gain-Bandwidth Product
3
Input Leakage Current
f
OSC
SYNC = AGND, 5.5 V ≤ VIN ≤ 25 V
SYNC = INTVCC, 5.5 V ≤ VIN ≤ 25 V
175
250
230
210
300
245
350
350
0.4
kHz
kHz
kHz
V
V
µA
V
V
%
%
µA
dB
MHz
nA
t
F
≤ 200 ns
t
R
≤ 200 ns
SYNC = 5 V
PWRGD
10 kΩ pull-up to 5 V
10 kΩ pull-up to 5 V, FB5 < 90% of nominal
output value
FB5 rising; with respect to nominal output
FB5 falling; with respect to nominal output
CPOR = 1.2 V
2.8
0.5
4.8
0.4
–6.0
–3.0
–3.7
4
–1
47
10
–1.5
–0.3
GBW
I
EAN
ADJ/FX5 = ADJ/FX3 = 5 V
200
Rev. A | Page 3 of 24
ADP3025
SPECIFICATIONS
(continued)
Parameter
MAIN SMPS CONTROLLERS
Fixed 5 V Output Voltage
Fixed 3.3 V Output Voltage
Adjustable Output Voltage
Output Voltage Adjustment Range
3
Current Limit Threshold
CLSET5 = CLSET3 = Floating
CLSET5 = CLSET3 = 0 V
Soft Start Current
Soft Start Turn-On Threshold
Feedback Input Leakage Current
Maximum Duty Cycle
3
Transition Time (DRVL)
Rise
Fall
Transition Time (DRVH)
Rise
Fall
Logic Input Voltage
ADJ/FX3, ADJ/FX5, SD
Logic Low
Logic High
LINEAR REGULATOR CONTROLLER
Feedback Threshold
COMP2/SD2 Pull-Up Current
COMP2/SD2 Threshold
DC Gain
3
Transconductance g
m 3
Gain-Bandwidth Product
3
FB2 Input Leakage Current
POWER-FAIL COMPARATOR
PFI Input Threshold
PFI Input Hysteresis
PFI Input Current
PFO High Voltage
PFO Low Voltage
FAULT PROTECTION
Output Overvoltage Trip Threshold
Output Undervoltage Lockout Threshold
Symbol
FB5
FB3
FB5, FB3
Conditions
5.5 V ≤ VIN ≤ 25 V, ADJ/FX5 = 0 V
5.5 V ≤ VIN ≤ 25 V, ADJ/FX3 = 0 V
5.5 V ≤ VIN ≤ 25 V,
ADJ/FX5 = ADJ/FX3 = 5 V
ADJ/FX5 = ADJ/FX3 = 5 V
5.5 V = VIN = 25 V, T
A
= 25°C
5.5 V ≤ VIN ≤ 25 V, T
A
= 25°C
SS3 = SS5 = 3 V
SS5, SS3
I
FB
D
MAX
t
R
(DRVL)
t
F
(DRVL)
t
R
(DRVH)
t
F
(DRVH)
ADJ/FX5 = ADJ/FX3 = 5 V, FB = 800 mV
VIN = 5.5 V, SYNC = AGND
C
LOAD
= 3000 pF, 10% to 90%
C
LOAD
= 3000 pF, 90% to 10%
C
LOAD
= 3000 pF, 10% to 90%
C
LOAD
= 3000 pF, 90% to 10%
Min
4.90
3.234
776
0.800
54
240
0.7
0.4
94
72
300
2.1
0.6
99
40
45
50
50
70
70
100
100
Typ
5.0
3.3
800
Max
5.10
3.366
824
6.0
90
360
3.8
0.8
600
Unit
V
V
mV
V
mV
mV
µA
V
nA
%
ns
ns
ns
ns
VIL
VIH
FB2
COMP2/SD2
0.6
2.9
776
COMP2/SD2 = 0 V
0.5
COMP2/SD2 = 3 V
800
2.8
0.85
62
0.3
20
20
800
14
824
1.1
V
V
mV
µA
V
dB
ms
MHz
nA
mV
mV
nA
V
V
%
%
GBW
I
FB2
PFI
I
PFI
PFO
H
PFO
L
FB2 = 800 mV
PFO from high to low
776
824
500
10 kΩ pull-up to 5 V
10 kΩ pull-up to 5 V
With respect to nominal output
With respect to nominal output
4.8
0.4
115
70
120
80
125
90
1
2
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC) methods.
The reference’s line regulation error is insignificant. The reference is not supposed to be loaded externally.
3
Guaranteed by design, not tested in production.
Rev. A | Page 4 of 24
ADP3025
ABSOLUTE MAXIMUM RATINGS
Table 2. ADP3025 Stress Ratings
Parameter
VIN to AGND
AGND to PGND
INTVCC
BST5, BST3 to PGND
BST5 to SW5
BST3 to SW3
CS5, CS3
SW3, SW5 to PGND
SD
DRVL5/3 to PGND
DRVH5/3 to SW5/3
All Other Inputs and Outputs
θ
JA
Operating Ambient Temperature
Range
Junction Temperature Range
Storage Temperature Range
Lead Temperature Range
(Soldering 10 sec)
Rating
–0.3 V to +27 V
±0.3 V
AGND – 0.3 V to +6 V
–0.3 V to +32 V
–0.3 V to +6 V
–0.3 V to +6 V
AGND – 0.3 V to VIN
–2 V to VIN + 0.3 V
AGND – 0.3 V to +27 V
–0.3 V to INTVCC + 0.3 V
–0.3 V to INTVCC + 0.3 V
AGND – 0.3 V to
INTVCC + 0.3 V
98°C/W
0°C to 70°C
0°C to 150°C
–65°C to +150°C
300°C
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 listed in the operational sections
of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
this product features proprietary ESD protection circuitry, permanent damage may occur on devices
subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
recommended to avoid performance degradation or loss of functionality.
Rev. A | Page 5 of 24
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