AP3418
Document number: DS37233 Rev. 2 - 2
1 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
Description
The AP3418 is a 1.4MHz fixed frequency, current mode, PWM
synchronous buck (step-down) DC-DC converter, capable of driving a
1.5A load with high efficiency, excellent line and load regulation. The
device integrates synchronous P-channel and N-channel power
MOSFET switches with low on-resistance. It is ideal for powering
portable equipment that runs from a single Li-ion battery.
A standard series of inductors are available from several different
manufacturers optimized for use with the AP3418. This feature greatly
simplifies the design of switch-mode power supplies.
The AP3418 is available in SOT25 package.
Features
Input Voltage Range: 2.5V to 5.5V
Output Voltage: 0.6V to VIN
ADJ Output
Fixed 1.4MHz Frequency
High Efficiency up to 95%
Output Current: 1.5A
Current Mode Control
100% Duty Cycle in Dropout
Built-in Over Current Protection
Built-in Short Circuit Protection
Built-in Thermal Shutdown Protection
Built-in UVLO Function
Built-in Soft-start
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Pin Assignments
(Top View)
SOT25
Applications
LCD TV
Set-top Box
Datacom
Portable Device
Smart Phone
AP3418-ADJ
L
C
OUT
C
IN
V
IN
R2 R1
V
OUT
4.7F
2.2H
22F
EN
VIN
SW
FB
GND
1
4
3
2
5
1
2
3 4
5
EN
GND
SW
FB
VIN
1.5A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter
Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
Typical Applications Circuit
AP3418
Document number: DS37233 Rev. 2 - 2
2 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
Pin Number
Pin Name
Function
1
EN
Control input pin. Forcing this pin above 1.5V enables the IC. Forcing this
pin below 0.4V shuts down the IC. When the IC is in shutdown mode, all
functions are disabled to decrease the supply current below 1µA
2
GND
Ground pin
3
SW
Power switch output pin. Inductor connection to drain of the internal PFET
and NFET switches
4
VIN
Supply input pin. Bypass to GND with a 4.7µF or greater ceramic
capacitor
5
FB
This is the feedback pin of the device. Connect this pin directly to the
output if the fixed output voltage version is used. For the adjustable
version, an external resistor divider is connected to this pin
VOLTAGE
REFERENCE
OSCILLATOR
CURRENT
SENSE
ERROR
AMPLIFIER
PWM
COMPARATOR
MAX
CURRENT LIMIT
0.6V
V
OCP
0.4V
LOGIC
CLK
DRIVER
SHORT
CIRCUIT
PROTECTION
REVERSE
COMPARATOR
EN
FB
GND
SW
GNDVIN
VIN
1
5
2
4
3
4
2
Pin Descriptions
Functional Block Diagram
AP3418
Document number: DS37233 Rev. 2 - 2
3 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
Symbol
Parameter
Rating
Unit
VIN
Input Voltage
-0.3 to 6.0
V
VFB
Feedback Voltage
-0.3 to VIN +0.3
V
VEN
EN Pin Voltage
-0.3 to VIN+0.3
V
VSW
SW Pin Voltage
-0.3 to VIN+0.3
V
θ
JA
Thermal Resistance
265
ºC/W
TJ
Operating Junction Temperature
+150
ºC
T
STG
Storage Temperature
-65 to +150
ºC
T
LEAD
Lead Temperature (Soldering, 10sec)
+260
ºC
–
ESD(Machine Model)
200
V
–
ESD(Human Body Model)
2000
V
Symbol
Parameter
Min
Max
Unit
VIN
Input Voltage
2.5
5.5
V
TA
Operating Ambient Temperature
-40
+85
ºC
Absolute Maximum Ratings (Note 4)
Note 4: 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
AP3418
Document number: DS37233 Rev. 2 - 2
4 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
VIN
Input Voltage
–
2.5 – 5.5
V
IQ
Quiescent Current
V
FB
= 0.65V
–
62
100
µA
I
STBY
Shutdown Supply Current
V
EN
= GND
–
0.1 1 µA
V
REF
Reference Voltage
For Adjustable Output
Voltage
0.588
0.6
0.612
V
I
FB_H
Feedback Bias Current
V
FB
= 1V
-0.1 – 0.1
µA
I
FB_L
V
FB
= 0V
-0.1 – 0.1
R
DS(ON)_ P
PMOSFET RON
ISW = 200mA
–
0.2 – Ω
R
DS(ON) _N
NMOSFET RON
ISW = -200mA
–
0.15 – Ω
I
LIM
Switch Current Limit
V
FB
= 0.55V
1.8
2.3 – A
VH
EN Pin Threshold
–
1.5 – –
V
VL
– – –
0.4
V
UVLO
UVLO Threshold
VIN Rising
–
2.3
–
V
V
HYS
UVLO Hysteresis
– – 0.2
–
f
OSC
Oscillator Frequency
–
1.12
1.40
1.68
MHz
D
MAX
Max. Duty Cycle
–
100 – –
%
D
MIN
Min. Duty Cycle
– – –
0
I
SW_H
SW Leakage Current
VSW = 0V
–
0.1
–
µA
I
SW_L
VSW = 5V
–
0.1
–
tSS
Soft-start Time
– – 1 – ms
T
OTSD
Thermal Shutdown
– – +160 – ºC
T
HYS
Thermal Shutdown Hysteresis
– – +20 – ºC
Electrical Characteristics (V
= 5V, TA = +25ºC, unless otherwise specified.)
IN
AP3418
Document number: DS37233 Rev. 2 - 2
5 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
-40 -20 0 20 40 60 80 100 120 140
1.8
2.0
2.2
2.4
2.6
2.8
Temperature (
o
C)
Switch Current Limit (A)
VIN = 5.0V
-40 -20 0 20 40 60 80 100 120 140
0.56
0.57
0.58
0.59
0.60
0.61
0.62
0.63
0.64
Temperature (
o
C)
Reference Voltage (V)
VIN = 5.0V
2.5 3.0 3.5 4.0 4.5 5.0 5.5
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
1.65
1.70
Input Voltage (V)
Frequency (MHz)
-40 -20 0 20 40 60 80 100 120 140
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
Temperature (
o
C)
Frequency (MHz)
VIN = VEN = 5.0V
2.5 3.0 3.5 4.0 4.5 5.0 5.5
40
45
50
55
60
65
70
75
80
85
90
95
100
Input Voltage (V)
Efficiency (%)
V
OUT
= 1.8V
I
OUT
= 1.5A
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
60
65
70
75
80
85
90
95
100
Output Current (A)
Efficiency (%)
VIN = 5.0V
V
OUT
=1.8V
Performance Characteristics (V
Efficiency vs. Output Current Efficiency vs. Input Voltage
Reference Voltage vs. Temperature Switch Current Limit vs. Temperature
Frequency vs. Input Voltage Frequency vs. Temperature
= 5V, TA = +25ºC, unless otherwise specified.)
IN
AP3418
Document number: DS37233 Rev. 2 - 2
6 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
-40 -20 0 20 40 60 80 100 120 140
0.0
0.1
0.2
0.3
0.4
0.5
Temperature (
o
C)
PMOS R
DS(ON)_UP
(
VIN = 5.0V
ISW = 200mA
-40 -20 0 20 40 60 80 100 120 140
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
Temperature (
o
C)
NMOS R
DS(ON)_DOWN
()
VIN = 5.0V
ISW = 200mA
Time 1µs/div
VSW
2V/div
IL
1A/div
V
OUT_AC
10mV/div
VSW
2V/div
IL
200mA/div
Time 10ms/div
V
OUT_AC
10mV/div
Time 200μs/div
V
OUT
1V/div
IL
1A/div
V
EN
5V/div
VSW
2V/div
Time 200μs/div
V
OUT
1V/div
IL
1A/div
V
EN
5V/div
VSW
2V/div
Performance Characteristics (Cont. V
R
DS (ON)_UP
vs. Temperature R
Output Ripple (I
= 0A) Output Ripple (I
OUT
= 5V, TA = +25ºC, unless otherwise specified.)
IN
DS (ON)_DOWN
vs. Temperature
= 1.5A)
OUT
Enable Turn on (I
= 1.5A) Enable Turn off (I
OUT
OUT
= 1.5A)
AP3418
Document number: DS37233 Rev. 2 - 2
7 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
IL
1A/div
V
OUT
2V/div
VSW
5V/div
IL
1A/div
V
OUT
2V/div
VSW
5V/div
Time 10ms/div
Time 10ms/div
Performance Characteristics (Cont. V
= 5V, TA = +25ºC, unless otherwise specified.)
IN
Short Circuit Protection Short Circuit Protection Recovery
(I
= 1.5A) (I
OUT
OUT
= 1.5A)
AP3418
Document number: DS37233 Rev. 2 - 2
8 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
AP3418 X XX - XX
PackingPackageProduct Name
TR : Tape & Reel
K : SOT25
G1 : Green
RoHS/Green
Package
Temperature
Range
Part Number
Marking ID
Packing
SOT25
-40 to +85 ºC
AP3418KTR-G1
G5E
3000/Tape & Reel
: Logo
G5E: Marking ID
Ordering Information
Diodes IC’s Pb-free products with "G1" suffix in the part number, are RoHS compliant and green.
Marking Information
(Top View)
AP3418
Document number: DS37233 Rev. 2 - 2
9 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
2.820(0.111)
2.650(0.104)
1
.
500
(
0
.
059
)
0
.
000
(
0
.
000
)
0.300(0.012)
0.950(0.037)
0
.
900
(
0
.
035
)
0.100(0.004)
0.200(0.008)
0
.
300
(
0
.
012
)
8°
0°
3.100(0.122)
1
.
700
(
0
.
067
)
3
.
000
(
0
.
118
)
0.500(0.020)
0
.
150
(
0
.
006
)
1
.300(
0.051
)
0.200(0.008)
0
.
600
(
0
.
024
)
1.800(0.071)
2.000(0.079)
0
.
700
(
0
.
028
)
REF
TYP
1
.
450
(
0
.
057
)
MAX
Package Outline Dimensions (All dimensions in mm(inch).)
(1) Package Type: SOT25
AP3418
Document number: DS37233 Rev. 2 - 2
10 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
E2
E1
Y
X
G
Z
Dimensions
Z
(mm)/(inch)
G
(mm)/(inch)
X
(mm)/(inch)
Y
(mm)/(inch)
E1
(mm)/(inch)
E2
(mm)/(inch)
Value
3.600/0.142
1.600/0.063
0.700/0.028
1.000/0.039
0.950/0.037
1.900/0.075
Suggested Pad Layout
(1) Package Type: SOT25
AP3418
Document number: DS37233 Rev. 2 - 2
11 of 11
www.diodes.com
April 2014
© Diodes Incorporated
AP3418
A Product Line of
Diodes Incorporated
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.
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 © 2014, Diodes Incorporated
www.diodes.com
IMPORTANT NOTICE
LIFE SUPPORT
Loading...