PART OBSOLETE - USE AP62300
AP3503E
340kHZ 3A SYNCHRONOUS DC-DC BUCK CONVERTER
OBSOLETE – PART DISCONTINUED
Description
Pin Assignments
The AP3503E is a 340kHz fixed frequency, current mode, PWM
synchronous buck (step-down) DC-DC converter, capable of driving a
3A load with high efficiency and excellent line and load regulation.
The AP3503E exhibits high efficiency at light load. The device
integrates N-channel power MOSFET switches with low onresistance. Current mode control provides fast transient response and
cycle-by-cycle current limit.
(Top View)
The AP3503E employs complete protection to ensure system
security. Including output Overvoltage protection, input Undervoltage
Lock Out, programmable Soft Start, Over Temperature protection and
hiccup mode Short Circuit Protection.
BS
1
IN
2
SW
3
GND
4
EP
8
SS
7
EN
6
COMP
5
FB
PSOP-8
This IC is available in PSOP-8 package.
Features
Applications
Input Voltage Range: 4.5V to 18V
LCD TV
Fixed 340kHz Frequency
Set Top Box
High Efficiency at Light Load
Portable DVD
High Efficiency: up to 95%
Digital Photo Frame
Output Current: 3A
Current Mode Control
Built-In Over Current Protection
Built-In Thermal Shutdown Function
Built-In UVLO Function
Built-In Over Voltage Protection
Programmable Soft-Start
Hiccup Mode SCP
AP3503E
Document number: DS41539 Rev. 3 - 4
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AP3503E
Typical Applications Circuit
R4
100k
1
2
Output Voltage=3.3V
L 10μH
C4
10nF
3
4
C22
C21
22μF/25V 22μF/25V
BS
IN
SW
GND
AP3503E
OBSOLETE – PART DISCONTINUED
Input Voltage=12V
SS
EN
COMP
FB
C12
10μF/25V
C11
10μF/25V
8
C5
0.1μF
7
C6
Optional
6
C3
3.3nF
5
R2
D1
Optional
R3
13k
10k
R1
26.1k
Pin Descriptions
Pin Number
Pin Name
1
BS
2
IN
3
SW
Power switch output pin. This pin is connected to the inductor and bootstrap capacitor
4
GND
Ground pin
5
FB
6
COMP
7
EN
8
SS
_
EP
AP3503E
Document number: DS41539 Rev. 3 - 4
Function
Bootstrap pin. A bootstrap capacitor is connected between the BS pin and SW pin. The voltage across
the bootstrap capacitor drives the internal high-side power MOSFET
Supply power input pin. A capacitor should be connected between the IN pin and GND pin to keep the
input voltage constant
Feedback pin. This pin is connected to an external resistor divider to program the system output
voltage. When the FB pin voltage exceeds 1.1V, the over voltage protection is triggered. When the FB
pin voltage is below 0.3V, the oscillator frequency is lowered to realize short circuit protection
Compensation pin. This pin is the output of the transconductance error amplifier and the input to the
current comparator. It is used to compensate the control loop. Connect a series RC network from this
pin to GND. In some cases, an additional capacitor from this pin to GND pin is required
Control input pin. EN is a digital input that turns the regulator on or off. Drive EN high/low to turn on/off
the regulator. Pull up with 100kΩ resistor for automatic startup
Soft-start control input pin. SS controls the soft-start period. Connect a capacitor from SS to GND to set
the soft-start period. A 0.1μF capacitor sets the soft-start period to 15ms. To disable the soft-start
feature, leave SS unconnected
Exposed pad. It should be connected to GND in PCB layout
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AP3503E
Functional Block Diagram
OBSOLETE – PART DISCONTINUED
IN
2
SHUTDOWN
COMPARATOR
1.5V
VA
INTERNAL
REGULATOR
0.3V
VB
SLOP
COMP
CURRENT
SENSE
AMPLIFIER
VA
+
OSCILLATOR
SCP
90K/340K
1
BS
M1
CLK
LOCK
EN
COMPARATOR
7
S
Q
R
Q
PWM
COMPARATOR
3
SW
M2
2.5V
VB
1.1V
5 mA
SS
8
0. 925V
FB
Document number: DS41539 Rev. 3 - 4
GND
EA
5
AP3503E
4
6
COMP
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AP3503E
Absolute Maximum Ratings (Note 1)
OBSOLETE – PART DISCONTINUED
Symbol
Parameter
Value
Unit
VIN
IN Pin Voltage
-0.3 to 20
V
VEN
EN Pin Voltage
-0.3 to VIN
V
VSW
SW Pin Voltage
21
V
VBS
BS Pin Voltage
-0.3 to VSW+6
V
VFB
FB Pin Voltage
-0.3 to 6
V
COMP Pin Voltage
-0.3 to 6
V
VSS
SS Pin Voltage
-0.3 to 6
V
θJA
Thermal Resistance
60
ºC/W
TJ
Operating Junction Temperature
+150
ºC
-65 to +150
ºC
VCOMP
TSTG
Storage Temperature
TLEAD
Lead Temperature (Soldering, 10sec)
+260
ºC
VHBM
ESD (Human Body Model)
2000
V
VMM
ESD (Machine Model)
200
V
Note 1:
Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “Recommended Operating Conditions” is not implied.
Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability.
Recommended Operating Conditions
Symbol
Parameter
Min
Max
Unit
VIN
Input Voltage
4.5
18
V
TA
Operating Ambient Temperature
-40
+85
ºC
AP3503E
Document number: DS41539 Rev. 3 - 4
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AP3503E
Electrical Characteristics
Symbol
(TA=+25ºC, VIN=VEN=12V, VOUT=3.3V, unless otherwise specified.)
Parameter
Conditions
Min
Typ
Max
Unit
4.5
–
18
V
OBSOLETE – PART DISCONTINUED
SUPPLY VOLTAGE (IN PIN)
VIN
Input Voltage
–
IQ
Quiescent Current
VFB=1V, VEN=3V
–
1.2
1.4
mA
Shutdown Supply Current
VEN=0V
–
0.1
10
μA
3.65
4.00
4.25
V
ISHDN
UNDER VOLTAGE LOCKOUT
VUVLO
Input UVLO Threshold
VIN Rising
VHYS
Input UVLO Hysteresis
–
–
200
–
mV
ENABLE (EN PIN)
_
EN Shutdown Threshold Voltage
–
1.1
1.5
2
V
_
EN1Shutdown1Threshold1Voltage1
Hysteresis (Note 3)
–
–
350
–
mV
_
EN Lockout Threshold Voltage
–
2.2
2.5
2.7
V
_
EN Lockout Hysteresis
–
–
210
–
mV
Feedback Voltage
–
0.907
0.925
0.943
V
Feedback Over Voltage Threshold
–
–
1.1
–
V
Feedback Bias Current
VFB=1V
-0.1
–
0.1
μA
RDSONH
High-Side Switch On-resistance (Note 2)
ISW=0.2A/0.7A
–
100
–
mΩ
RDSONL
Low-Side Switch On-resistance (Note 2)
ISW=-0.2A/-0.7A
–
100
–
mΩ
High-Side Switch Leakage Current
VIN=18V, VEN=VSW=0V
–
0.1
10
μA
ILIMH
High-Side Switch Current Limit
–
4.3
5.6
–
A
ILIML
Low-Side Switch Current Limit
Drain to Source
–
0
–
mA
VOLTAGE REFERENCE (FB PIN)
VFB
VFBOV
IFB
MOSFET
CURRENT LIMIT
ILEAKH
SWITCHING REGULATOR
fOSC1
Oscillator Frequency
–
280
340
400
kHz
fOSC2
Short Circuit Oscillator Frequency
–
–
90
–
kHz
DMAX
Max. Duty Cycle
VFB=0.85V
–
90
–
%
DMIN
Min. Duty Cycle
VFB=1V
–
–
0
%
AP3503E
Document number: DS41539 Rev. 3 - 4
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AP3503E
Electrical Characteristics
Symbol
(Cont. TA=+25ºC, VIN=VEN=12V, VOUT=3.3V, unless otherwise specified.)
Parameter
Conditions
Min
Typ
Max
Unit
OBSOLETE – PART DISCONTINUED
ERROR AMPLIFIER
AEA
Error Amplifier Voltage Gain (Note 3)
–
–
400
–
V/V
GEA
Error Amplifier Transconductance
–
–
800
–
μA/V
GCS
COMP to Current Sense
Transconductance
–
–
5.2
–
A/V
THERMAL SHUTDOWN
TOTSD
Thermal Shutdown (Note 3)
–
–
+160
–
ºC
THYS
Thermal Shutdown Hysteresis (Note 3)
–
–
+20
–
ºC
Soft-Start Time (Note 3)
C5=0.1μF
–
15
–
ms
Soft-Start Current
–
–
5
–
μA
SOFT START (SS PIN)
tSS
–
Notes:
2. RDSON=
VSW1 - VSW2
.
ISW1 - ISW2
3. Not tested, guaranteed by design.
AP3503E
Document number: DS41539 Rev. 3 - 4
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AP3503E
Performance Characteristics (TA=+25ºC, VIN=12V, VOUT=3.3V, unless otherwise noted.)
Quiescent Current vs. Temperature
1.30
90
1.25
1.20
Quiescent Current (mA)
80
Efficiency (%)
70
60
50
40
o
VOUT=3.3V,L=10mH,TA=25 C
30
VIN=5V
0.1
1.10
1.05
1.00
0.95
0.85
10
0.01
1.15
0.90
VIN=12V
20
0.80
1
-50
-25
0
25
75
100
125
150
2.8
3.2
Temperature ( C)
Feedback Voltage vs. Temperature
Output Voltage vs. Load Current
1.2
3.6
1.1
3.5
1.0
3.4
Output Voltage (V)
Feedback Voltage (V)
50
o
Load Current (A)
0.9
0.8
3.3
3.2
3.1
0.7
3.0
0.6
0.0
-50
-25
0
25
50
75
100
125
0.4
0.8
150
1.2
1.6
2.0
2.4
Load Current (A)
o
Temperature ( C)
Output Voltage vs.
Input Voltage
Maximum Load Current vs.
Input Voltage
3.6
6
3.5
Maximum Load Current (A)
5
Output Voltage (V)
OBSOLETE – PART DISCONTINUED
Efficiency vs. Load Current
100
3.4
3.3
3.2
IOUT=1.5A
3.1
4
3
2
VOUT=3.3V
L=10mH
1
3.0
4
8
12
16
20
AP3503E
Document number: DS41539 Rev. 3 - 4
4
8
12
16
20
Input Voltage (V)
Input Voltage (V)
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AP3503E
Performance Characteristics (Cont.
TA=+25ºC, VIN=12V, VOUT=3.3V, unless otherwise noted.)
Output Ripple (IOUT=3A)
Load Transient (IOUT=1.5 to 3A)
OBSOLETE – PART DISCONTINUED
VIN(AC)
200mV/div
VOUT (AC)
100mV/div
VOUT (AC)
10mV/div
IL
1A/div
IOUT
1A/div
VSW
10V/div
Time 200μs/div
Time 2μs/div
Enable Turn-on Characteristic
(VIN=12V, VEN=3.3V, VOUT=3.3V, IOUT=3A)
Enable Turn-off Characteristic
(VIN=12V, VEN=3.3V, VOUT=3.3V, IOUT=3A)
VEN
2V/div
VEN
2V/div
VSS
2V/div
VSS
2V/div
VOUT
2V/div
VOUT
2V/div
IL
2A/div
IL
2A/div
Time 10ms/div
Time 200μs/div
Short Circuit Protection (IOUT=3A)
Short Circuit Recovery (IOUT=3A)
VOUT
2V/div
VOUT
2V/div
VSW
10V/div
VSW
10V/div
VSS
1V/div
VSS
1V/div
IL
2A/div
IL
2A/div
Time 10ms/div
AP3503E
Document number: DS41539 Rev. 3 - 4
Time 100ms/div
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AP3503E
Ordering Information
OBSOLETE – PART DISCONTINUED
AP3503E X X - X
Product Name
Package
Packing
RoHS/Green
MP : PSOP-8
TR : Tape & Reel
Blank : Tube
G1:RoHS Compliant
and Green
Package
Temperature Range
PSOP-8
-40 to +85C
AP3503E
Document number: DS41539 Rev. 3 - 4
Part Number
Marking ID
Packing
AP3503EMP-G1
3503EMP-G1
Tube
AP3503EMPTR-G1
3503EMP-G1
Tape & Reel
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AP3503E
Package Outline Dimensions (All dimensions in mm(inch).)
(1)
Package Type: PSOP-8
3.800(0.150)
OBSOLETE – PART DISCONTINUED
4.000(0.157)
2.313(0.091)
3.202(0.126)
3.402(0.134)
2.513(0.099)
1.270(0.050)
TYP
4.700(0.185)
5.100(0.201)
0.330(0.013)
0.510(0.020)
5.800(0.228)
6.200(0.244)
0.050(0.002)
0.150(0.006)
1.350(0.053)
1.550(0.061)
1.350(0.053)
0°
8°
1.750(0.069)
0.400(0.016)
1.270(0.050)
0.170(0.007)
0.250(0.010)
Note: Eject hole, oriented hole and mold mark is optional.
AP3503E
Document number: DS41539 Rev. 3 - 4
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AP3503E
IMPORTANT NOTICE
OBSOLETE – PART DISCONTINUED
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume
all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated
website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or
indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
noted herein may also be covered by one or more United States, international or foreign trademarks.
This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any
use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2020, Diodes Incorporated
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AP3503E
Document number: DS41539 Rev. 3 - 4
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