AP3402

AP3402
1.0MHZ, 2A STEP-DOWN DC-DC BUCK CONVERTER
Description
Pin Assignments
The AP3402 is a 2A step-down DC-DC converter. At heavy load, the
constant frequency PWM control performs excellent stability and
transient response. No external compensation components are
required.
(Top View)
Pin 1 Mark
The AP3402 supports a range of input voltages from 2.7V to 5.5V,
allowing the use of a single Li+/Li- polymer cell, multiple
Alkaline/NiMH cell, and other standard power sources. The output
voltage is adjustable from 0.6V to the input voltage. The AP3402
employs internal power switch and synchronous rectifier to minimize
external part count and realize high efficiency. During shutdown, the
input is disconnected from the output and the shutdown current is less
than 1μA. Other key features include over-temperature and short
circuit protection, and under-voltage lockout to prevent deep battery
discharge.
EN
1
6
FB
GND
2
5
PG
LX
3
4
VIN
TSOT26
The AP3402 delivers 2A maximum output current while consuming
only 90μA of no-load quiescent current. Ultra-low RDS(ON) integrated
MOSFETs and 100% duty cycle operation make the AP3402 an ideal
choice for high output voltage, high current applications which require
a low dropout threshold.
The AP3402 is available in TSOT26 package.
Features


Output Current: Up to 2A
Output Voltage: 0.6V to VIN














Input Voltage: 2.7V to 5.5V
Peak Efficiency Up to 95%
90μA (Typ) No Load Quiescent Current
Shutdown Current: <1μA
100% Duty Cycle Operation
1MHz Switching Frequency
Power Good Indicator Function
Internal Soft Start
No External Compensation Required
Current Limit Protection
Thermal Shutdown
TSOT26 Package
Totally Lead-free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Notes:
Applications






5V or 3.3V Point of Load Conversion
Telecom/Networking Equipment
Set Top Boxes
Storage Equipment
Video Cards
DDR Power Supply
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.
AP3402
Document number: DS36623 Rev. 4- 2
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AP3402
Typical Applications Circuit
VIN =2.7V to 5.5V
OFF
EN
100k
AP3402
CIN
22mF
ON
VIN
PG
L1 2.2mH
VOUT=1.8V
LX
C1
22pF
R1
300k
COUT
22mFx2
FB
GND
R2
150k
Pin Descriptions
Pin Number
Pin Name
Function
1
EN
Enable control input. Force this pin voltage above 1.5V enables the chip, and below
0.4V shuts down the device
2
GND
3
LX
The drains of the internal main and synchronous power MOSFET
4
VIN
Bias supply. Chip main power supply pin
5
PG
Power good indicator, open drain output. PG is pulled up to VIN when the output
voltage is within 20% of the regulation level, otherwise it is low
6
FB
Feedback voltage to internal error amplifier, the threshold voltage is 0.6V
AP3402
Document number: DS36623 Rev. 4- 2
Ground pin
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AP3402
Functional Block Diagram
4
VIN
+
SLOPE COMP
+
_
6
FB
____
OSC
S
Q
R
_
Q
_
+ EA
+
0.6 V REF
IAMP
_
FREQ
SHIFT
PWM
COMP
+
1 M OSC
SWITCHING
LOGIC AND
BLOCKING
CIRCUIT
3
LX
ANTI SHOOT
THRU
1
EN
PG
5
CONTROL
LOGIC
2
SHUTDOWN
GND
Absolute Maximum Ratings (Note 4)
Symbol
Parameter
Rating
Unit
-0.3 to 6
V
EN Pin Voltage
-0.3 to VIN +0.3
V
VLX
LX Pin Voltage
-0.3 to VIN +0.3
V
VIN
Input Voltage
VEN
VLX
LX Pin Voltage
-3 to VIN +3 for <20nS
V
VFB
Feedback Pin Voltage
-0.3 to VIN +0.3
V
VPG
PG Pin Voltage
-0.3 to VIN +0.3
V
JA
Thermal Resistance (Junction to Ambient)
TJ
Operating Junction Temperature
TSOT26
220
°C/W
+150
°C
TSTG
Storage Temperature
-65 to +150
°C
TLEAD
Lead Temperature (Soldering, 5 sec)
+300
°C
VMM
ESD (Machine Model)
200
V
VHBM
ESD (Human Body Model)
2000
V
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
Symbol
Min
Max
VIN
Input Voltage Range
Parameter
2.7
5.5
V
TA
Operating Ambient Temperature
-40
+85
°C
TJ
Junction Temperature Range
-40
+125
°C
AP3402
Document number: DS36623 Rev. 4- 2
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Unit
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AP3402
Electrical Characteristics (@VIN = 5V, VOUT = 1.8V, L = 2.2µH, COUT = 22µF×2, TA = +25°C, unless otherwise specified.)
Symbol
Min
Typ
Max
Unit
Input Voltage Range
—
2.7
—
5.5
V
Output Voltage Range
—
0.6
—
VIN
V
VFB
Regulated Feedback Voltage
—
0.588
0.6
0.612
V
IFB
FB Leakage Current
VFB = 1V
—
—
0.2
μA
IQ
Quiescent Current
VFB = 0.65V
—
90
—
μA
ISD
Shutdown Current
—
—
1
μA
ILIM
Peak Inductor Current
VEN = 0V
—
3
—
—
A
fOSC
Oscillator Frequency
—
—
1
—
MHz
ILX = 100mA, high side
—
110
—
ILX = 100mA, low side
—
80
—
VIN
VOUT
RDS(ON)
Parameters
Drain to Source On-state Resistance
Conditions
mΩ
VENH
EN High Threshold
—
1.5
—
—
VENL
EN Low Threshold
—
—
—
0.4
V
EN Leakage Current
-1.0
—
1.0
μA
—
2.4
2.7
V
IEN
V
VUVLO
Input UVLO Threshold
VIN = VEN = 5V
—
VHYS
UVLO Hysteresis
—
—
0.2
—
V
TOTP
Over Temperature Protection
—
—
+160
—
°C
TOTH
OTP Hysteresis
—
—
+30
—
°C
VFBTH
Power Good Threshold (Relative to VFB)
—
—
±20
—
%
VIOVP
VIN Over Voltage Protection
—
—
6.25
—
V
VIHSY
IOVP Hysteresis
—
—
0.25
—
V
Soft-start Time
—
—
1.8
—
ms
tSS
AP3402
Document number: DS36623 Rev. 4- 2
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AP3402
Performance Characteristics (@TA = +25ºC, VIN = 5.0V, VOUT = 1.8V, unless otherwise specified.)
Efficiency vs. Load Current
Feedback Reference Voltage vs. Temperature
0.620
90
0.615
Feedback Reference Voltage (V)
100
80
Efficiency (%)
70
60
50
40
30
VIN=5V,VOUT=1.0V
VIN=5V,VOUT=1.8V
VIN=5V,VOUT=3.3V
20
10
10
100
0.605
0.600
0.595
0.590
0.585
0.580
-60
0
1
0.610
1000
-40
-20
0
20
40
60
80
100
120
140
o
Temperature ( C)
IOUT (mA)
PFET Drain-Source On-State Resistance vs. Temperature
NFET Drain-Source On-State Resistance vs. Temperature
120
200
190
110
180
NFET RDS(ON) (m)
PFET RDS(ON)(m)
170
160
150
140
130
100
90
80
70
120
60
110
100
-60
-40
-20
0
20
40
60
80
100
120
50
-60
140
-40
-20
0
Inductor Current Limit vs. Temperature
60
80
100
120
140
Oscillation Frequency vs. Temperature
4.6
1.20
4.4
1.15
4.2
1.10
Oscillation Frequency (MHz)
Inductor Current Limit (A)
40
o
Temperture ( C)
4.0
3.8
3.6
3.4
3.2
3.0
1.05
1.00
0.95
0.90
0.85
0.80
0.75
2.8
2.6
-60
20
Temperture ( C)
o
-40
-20
0
20
40
60
80
100
120
0.70
-60
140
-40
-20
0
20
40
60
80
100
120
140
o
Temperature ( C)
o
Temperature ( C)
AP3402
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AP3402
Performance Characteristics (@TA = +25ºC, VIN = 5.0V, VOUT = 1.8V, unless otherwise specified.)
Enable Turn on Characteristic (IOUT=2A)
Enable Turn off Characteristic (IOUT=2A)
VEN
(2V/div)
VEN
(2V/div)
VOUT
(1V/div)
VPG
(2V/div)
VOUT
(1V/div)
VPG
(2V/div)
IL
(2A/div)
IL
(2A/div)
Time (5ms/div)
Time (200µs/div)
Short Current Protection (IOUT=2A)
SCP Recovery (IOUT=2A)
VOUT
(1V/div)
VOUT
(1V/div)
IL
(2A/div)
IL
(2A/div)
VSW
(5V/div)
VSW
(5V/div)
Time (50ms/div)
Time (50ms/div)
Load Transient (IOUT=0.1A to 2A)
Load Transient (IOUT=1A to 2A)
VOUT_AC
(100mV/div)
VOUT_AC
(100mV/div)
IOUT
(1A/div)
IOUT
(1A/div)
Time (100µs/div)
AP3402
Document number: DS36623 Rev. 4- 2
Time (100µs/div)
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AP3402
Application Information
Typical application circuit is shown in the application circuit and for the circuit parameters setting please refers to the following descriptions.
Under Voltage Lockout (UVLO) Circuit
When the VIN drops lower than the UVLO detector threshold, the UVLO circuit starts to operate, V REF stops, and high-side switch and low-side
switch built-in switch transistors turn “OFF”. As a result, V OUT drops according to the COUT capacitance value and the load. When the VIN is rising
higher than UVLO released voltage, the IC will restart the operation.
Short Circuit Protection and Recovery
When the AP3402 output node is shorted to GND that VFB drops under 0.3V, the AP3402 will enter hiccup mode to protect itself. If short circuit is
removed, and VFB rises over 0.3V, the AP3402 recovers to normal operation again. If the AP3402 reaches OCP threshold while short circuit, the
AP3402 will enter cycle by cycle current limit mode until the current under OCP threshold.
Power Good
The PG pin output is an open drain MOSFET. The output is pulled low when the FB voltage enters the fault condition by falling below 80% or
rising above 120% of the nominal internal reference voltage. When the FB voltage rises to the good condition above 90% or falls below 110% of
the internal voltage reference PG output MOSET is turned off. It is recommended using a pull-up to VIN.
Over Temperature Protection
The internal thermal temperature protection circuitry is provided to protect the integrated circuit in the event that the maximum junction
temperature is exceeded. When the junction temperature exceeds +160oC, it shuts down the internal control circuit and switching power MOSFET.
The AP3402 will restart automatically under the control of soft start circuit when the junction temperature decreases to +130oC.
Input Over Voltage Protection
When input voltage of the AP3402 is near 6.25V, the IC will enter Input-Over-Voltage-Protection. It would be shut down and there will be no output
voltage in this state. As the input voltage goes down below 6V, it will leave input OVP and recover the output voltage.
AP3402
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AP3402
Ordering Information
AP3402 XX XX – XX
Product Name
Package
RoHS/Green
Packing
TR : Tape & Reel
KT : TSOT26
G1 : Green
Package
Temperature Range
Part Number
Marking ID
Packing
TSOT26
-40°C to +85°C
AP3402KTTR-G1
GND
3000 / Tape & Reel
Marking Information
(1)
TSOT26
(Top View)
6
5
4
GND
1
AP3402
Document number: DS36623 Rev. 4- 2
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First Line: Logo and Marking ID
3
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AP3402
Package Outline Dimensions
(1)
Package Type: TSOT26
D
e1
01(4x)
E1/2
E/2
E1
c
E
Gauge Plane
0
L
e
Seating Plane
L2
01(4x)
b
A2
A1
A
Seating Plane
TSOT26
Dim
Min
Max
Typ
A
1.00


A1
0.010 0.100

A2
0.840 0.900

D
2.800 3.000 2.900
E
2.800 BSC
E1
1.500 1.700 1.600
b
0.300 0.450

c
0.120 0.200

e
0.950 BSC
e1
1.900 BSC
L
0.30
0.50
L2
0.250 BSC
θ
0°
8°
4°
θ1
4°
12°

All Dimensions in mm
Suggested Pad Layout
(1)
Package Type: TSOT26
C
Dimensions Value (in mm)
C
0.950
X
0.700
Y
1.000
Y1
3.199
Y1
Y
X
AP3402
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AP3402
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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).
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written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
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AP3402
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