Data Sheet
FEATURES
Input voltage: 4.5 V to 20 V
Integrated MOSFET: 44 mΩ/11.6 mΩ
Reference voltage: 0.6 V ± 1%
Continuous output current: 4 A
Programmable switching frequency: 200 kHz to 1.4 MHz
Synchronizes to external clock: 200 kHz to 1.4 MHz
180° out-of-phase clock synchronization
Precision enable and power good
External compensation
Internal soft start with external adjustable option
Startup into a precharged output
Supported by ADIsimPower design tool
20 V, 4 A, Synchronous, Step-Down
DC-to-DC Regulator
ADP2384
TYPICAL APPLICATIONS CIRCUIT
ADP2384
V
IN
C
IN
PVIN
EN
PGOOD
SYNC
RT
R
T
C
VREG
VREG
GND
PGND
FB
COMP
SS
R
C
C
SS
BST
C
BST
SW
R
TOP
L
V
OUT
C
OUT
R
BOT
10725-001
C
C
Figure 1.
APPLICATIONS
Communications infrastructure
Networking and servers
Industrial and instrumentation
Healthcare and medical
Intermediate power rail conversion
DC-to-dc point-of-load applications
100
95
90
85
EFFICIENCY (%)
80
75
70
65
60
55
50
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
OUTPUT CURRENT (A)
V
OUT
= 1.2V
V
OUT
= 3.3V
V
OUT
= 5V
10725-002
Figure 2. Efficiency vs. Output Current, V
IN
= 12 V, f
SW
= 300 kHz
GENERAL DESCRIPTION
The
ADP2384
is a synchronous, step-down dc-to-dc regulator
with an integrated 44 mΩ, high-side power MOSFET and
an 11.6 mΩ, synchronous rectifier MOSFET to provide a high
efficiency solution in a compact 4 mm × 4 mm LFCSP package.
This device uses a peak current mode, constant frequency pulse-
width modulation (PWM) control scheme for excellent stability
and transient response. The switching frequency of the
ADP2384
can be programmed from 200 kHz to 1.4 MHz. To minimize
system noise, the synchronization function allows the switching
frequency to be synchronized to an external clock.
The
ADP2384
requires minimal external components and operates
from an input voltage of 4.5 V to 20 V. The output voltage can be
adjusted from 0.6 V to 90% of the input voltage and delivers up to
4 A of continuous current. Each IC draws less than 120 μA current
from the input source when it is disabled.
This regulator targets high performance applications that require
high efficiency and design flexibility. External compensation and an
adjustable soft start function provide design flexibility. The power-
good output and precision enable input provide simple and reliable
power sequencing.
Other key features include undervoltage lockout (UVLO),
overvoltage protection (OVP), overcurrent protection (OCP),
short-circuit protection (SCP), and thermal shutdown (TSD).
The
ADP2384
operates over the −40°C to +125°C junction
temperature range and is available in a 24-lead, 4 mm × 4 mm
LFCSP package.
Rev. 0
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: 781.461.3113
©2012 Analog Devices, Inc. All rights reserved.
ADP2384
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Typical Applications Circuit............................................................ 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
ESD Caution .................................................................................. 5
Pin Configuration and Function Descriptions ............................. 6
Typical Performance Characteristics ............................................. 7
Functional Block Diagram ............................................................ 11
Theory of Operation ...................................................................... 12
Control Scheme .......................................................................... 12
Precision Enable/Shutdown ...................................................... 12
Internal Regulator (VREG) ....................................................... 12
Bootstrap Circuitry .................................................................... 12
Oscillator ..................................................................................... 12
Synchronization .......................................................................... 12
Soft Start ...................................................................................... 13
Power Good................................................................................. 13
Peak Current-Limit and Short-Circuit Protection................. 13
Overvoltage Protection (OVP) ................................................. 14
Undervoltage Lockout (UVLO) ............................................... 14
Data Sheet
Thermal Shutdown .................................................................... 14
Applications Information .............................................................. 15
Input Capacitor Selection .......................................................... 15
Output Voltage Setting .............................................................. 15
Voltage Conversion Limitations ............................................... 15
Inductor Selection ...................................................................... 15
Output Capacitor Selection....................................................... 16
Programming the Input Voltage UVLO .................................. 17
Compensation Design ............................................................... 17
ADIsimPower Design Tool ....................................................... 17
Design Example .............................................................................. 18
Output Voltage Setting .............................................................. 18
Frequency Setting ....................................................................... 18
Inductor Selection ...................................................................... 18
Output Capacitor Selection....................................................... 19
Compensation Components ..................................................... 19
Soft Start Time Program ........................................................... 19
Input Capacitor Selection .......................................................... 19
Recommended External Components .................................... 20
Circuit Board Layout Recommendations ................................... 21
Typical Applications Circuits ........................................................ 22
Outline Dimensions ....................................................................... 23
Ordering Guide .......................................................................... 23
REVISION HISTORY
8/12—Revision 0: Initial Version
Rev. 0 | Page 2 of 24
Data Sheet
SPECIFICATIONS
ADP2384
V
PVIN
= 12 V, T
J
= −40°C to +125°C for minimum/maximum specifications, and T
A
= 25°C for typical specifications, unless otherwise noted.
Table 1.
Parameter
PVIN
PVIN Voltage Range
Quiescent Current
Shutdown Current
PVIN Undervoltage Lockout Threshold
FB
FB Regulation Voltage
FB Bias Current
ERROR AMPLIFIER (EA)
Transconductance
EA Source Current
EA Sink Current
INTERNAL REGULATOR (VREG)
VREG Voltage
Dropout Voltage
Regulator Current Limit
SW
High-Side On Resistance
1
Low-Side On Resistance
1
High-Side Peak Current Limit
Low-Side Negative Current-Limit
Threshold Voltage
2
SW Minimum On Time
SW Minimum Off Time
BST
Bootstrap Voltage
OSCILLATOR (RT PIN)
Switching Frequency
Switching Frequency Range
SYNC
Synchronization Range
SYNC Minimum Pulse Width
SYNC Minimum Off Time
SYNC Input High Voltage
SYNC Input Low Voltage
SS
Internal Soft Start
SS Pin Pull-Up Current
PGOOD
Power-Good Range
FB Rising Threshold
FB Rising Hysteresis
FB Falling Threshold
FB Falling Hysteresis
V
FB
I
FB
g
m
I
SOURCE
I
SINK
V
VREG
V
PVIN
= 12 V, I
VREG
= 50 mA
V
PVIN
= 12 V, I
VREG
= 50 mA
340
40
40
7.6
65
V
BST
− V
SW
= 5 V
V
VREG
= 8 V
4.8
0°C < T
J
< 85°C
−40°C < T
J
< 125°C
0.594
0.591
0.6
0.6
0.01
470
60
60
8
340
100
44
11.6
6.1
20
125
200
4.5
R
T
= 100 kΩ
530
200
200
100
100
1.3
5
600
0.606
0.609
0.1
600
80
80
8.4
135
70
20
7.4
V
V
µA
µS
µA
µA
V
mV
mA
mΩ
mΩ
A
mV
ns
ns
V
kHz
kHz
kHz
ns
ns
V
V
Clock cycles
µA
Symbol
V
PVIN
I
Q
I
SHDN
UVLO
Test Conditions/Comments
Min
4.5
2.1
45
3.5
Typ
Max
20
3.6
120
4.5
Unit
V
mA
µA
V
V
No switching
EN = GND
PVIN rising
PVIN falling
2.9
80
4.3
3.8
t
MIN_ON
t
MIN_OFF
V
BOOT
f
SW
f
SW
168
260
5.5
670
1400
1400
0.4
1600
3.2
I
SS_UP
2.5
3.9
PGOOD from low to high
PGOOD from high to low
PGOOD from low to high
PGOOD from high to low
95
5
105
11.7
%
%
%
%
Rev. 0 | Page 3 of 24
ADP2384
Parameter
Power-Good Deglitch Time
Power-Good Leakage Current
Power-Good Output Low Voltage
EN
EN Rising Threshold
EN Falling Threshold
EN Source Current
THERMAL SHUTDOWN
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
1
2
Data Sheet
Symbol
Test Conditions/Comments
PGOOD from low to high
PGOOD from high to low
V
PGOOD
= 5 V
I
PGOOD
= 1 mA
Min
Typ
1024
16
0.01
125
1.17
1.07
5
1
150
25
Max
Unit
Clock cycle
Clock cycle
µA
mV
V
V
µA
µA
°C
°C
0.1
200
1.28
0.97
EN voltage below falling threshold
EN voltage above rising threshold
Pin-to-pin measurement.
Guaranteed by design.
Rev. 0 | Page 4 of 24
Data Sheet
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
PVIN, EN, PGOOD
SW
BST
FB, SS, COMP, SYNC, RT
VREG
PGND to GND
Operating Junction Temperature Range
Storage Temperature Range
Soldering Conditions
Rating
−0.3 V to +22 V
−1 V to +22 V
V
SW
+ 6 V
−0.3 V to +6 V
−0.3 V to +12 V
−0.3 V to +0.3 V
−40°C to +125°C
−65°C to +150°C
JEDEC J-STD-020
ADP2384
THERMAL RESISTANCE
θ
JA
is specified for the worst-case conditions, that is, a device
soldered in a 4-layer, JEDEC standard circuit board for surface-
mount packages.
Table 3. Thermal Resistance
Package Type
24-Lead LFCSP_WQ
θ
JA
42.6
Unit
°C/W
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.
Rev. 0 | Page 5 of 24
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