Diodes AP3407A User Manual

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Data Sheet

General Description

The AP3407/A is a 1.4MHz fixed frequency, current
mode, PWM synchronous buck (step-down) DC-DC
converter, capable of driving a 1.2A 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 AP3407/A. This feature greatly simplifies
the design of switch-mode power supplies.

The AP3407/A is available in SOT-23-5.

Features

Input Voltage Range: 2.5V to 5.5V

•

• Output Voltage: 0.6V to V

• ADJ Output

• Fixed 1.4MHz Frequency

• High Efficiency up to 95%

• Output Current: 1.2A

• 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

IN

Applications

• Datacom

• Portable Device

• Smart Phone

SOT-23-5

Figure 1. Package Type of AP3407/A

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Pin Configuration

K Package
(SOT-23-5)

1

EN

GND

2

SW

34

(For AP3407) (For AP3407A)

Pin Description

Pin Number

AP3407 AP3407A

1 3 EN

2 2 GND Ground pin

3 5 SW

5

FB

VIN

1

VIN

GND

2

EN

34

Figure 2. Pin Configuration of AP3407/A (Top View)

Pin Name Function

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 1.2A

Power switch output pin. Inductor connection to drain
of the internal PFET and NFET switches

5

SW

FB

4 1 VIN

5 4 FB

Supply input pin. Bypass to GND with a 4.7µF or
greater ceramic capacitor

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.

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Functional Block Diagram

Figure 3. Functional Block Diagram of AP3407/A

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Ordering Information

AP3407 -

G1: Green

Circuit Type

Blank: AP3407

TR: Tape & Reel

A: AP3407A

K: SOT-23-5

Package

SOT-23-5 -40 to 85 ºC

BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant
and green.

Temperature

Range

Part Number Marking ID

Green Green

AP3407KTR-G1 GJA Tape & Reel
AP3407AKTR-G1 GJB Tape & Reel

Packing Type

Absolute Maximum Ratings (Note 1)

Parameter Symbol Value Unit

Input Voltage VIN -0.3 to 6.0 V
Feedback Voltage VFB -0.3 to VIN +0.3 V
EN Pin Voltage VEN -0.3 to VIN+0.3 V
SW Pin Voltage VSW -0.3 to VIN+0.3 V

Thermal Resistance
Thermal Resistance

θ

JA

θ

JC

265 ºC/W

60 ºC/W

Power Dissipation PD 0.377 W
Operating Junction Temperature TJ 150 ºC

Storage Temperature T
Lead Temperature (Soldering, 10sec) T

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.

Note 2: The junction temperature rise is given by T

θ

is the thermal resistance from junction of the die to the ambient temperature; The junction temperature, TJ is

JA

given by T

J=TA+TR

, where TA is the ambient temperature.

RISING=PD

-65 to 150 ºC

STG

260 ºC

LEAD

*θJA, where PD is the power dissipated by regulator,

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Input Voltage VIN 2.5 5.5 V
Maximum Output Current I

OUT (MAX)

1.2 A

Operating Ambient Temperature TA -40 85 ºC

Electrical Characteristics

VIN=V

DD =VPVDD

Parameters Symbol Conditions Min Typ Max Unit

Input Voltage VIN 2.5 5.5 V
Quiescent Current IQ V

Shutdown Supply Current I

Reference Voltage V

Feedback Bias Current IFB V

Output Voltage Accuracy

PMOSFET RON R

NMOSFET RON R

Switch Current Limit I

=3.3V, TA=25℃, unless otherwise specified.

=0.65V 62 100

FB

V

STBY

REF

∆V

OUT

ISW = 200mA

DS(ON)_ P

ISW = -200mA

DS(ON) _N

LIM

=GND 0.1 1

EN

For Adjustable Output
Voltage

-0.1 0.1

FB=VIN

-2 2 %

=0.55V 1.5 2.0 A

V

FB

µA
µA

0.588 0.6 0.612 V

µA

0.28

0.25

Ω

Ω

VH 1.5

EN Pin Threshold

V

VL 0.4

UVLO Threshold V

VDD Rising 2.3

UVLO

V

UVLO Hysteresis V

Oscillator Frequency f

Max. Duty Cycle D

0.2

HYS

1.12 1.40 1.68 MHz

OSC

VFB=0V 100

MAX

%

Min. Duty Cycle D
N-MOS SW Leakage

Current

V

MIN

V

=6.5V 0

FB

=3.3V, VSW=3.3V 0.1

IN

µA

Soft-start Time t 1 ms

Thermal Shutdown T
Thermal Shutdown

Hysteresis

160 ºC

OTSD

T

20 ºC

HYS

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Typical Performance Characteristics

100

95
90
85
80
75
70
65

Efficiency (%)

60
55
50
45
40

200 400 600 800 1000 1200

Output Current (mA)

VIN=3.3V

=2.5V

V

OUT

96

88

80

Efficiency (%)

72

23456

Figure 4. Efficiency vs. Output Current

Figure 5. Efficiency vs. Input Voltage

2.51

2.50

2.49

Output Voltage (V)

2.48

2.47
200 400 600 800 1000 1200

Output Current (mA)

VIN=3.3V
V

=2.5V

OUT

1.8

1.7

1.6

1.5

Frequency (MHz)

1.4

1.3

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5

Figure 6. Output Voltage vs. Output Current Figure 7. Frequency vs. Input Voltage

Input Voltage (V)

Input Voltage (V)

V

OUT

I

OUT

=2.5V

I

OUT

I

OUT

=300mA

=0.5A
=1.0A

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Typical Performance Characteristics (Continued)

1.7

1.6

1.5

1.4

Frequency (MHz)

1.3

1.2

-40 0 40 80 120 160

0.62

Temperature (OC)

VIN=3.3V
V

=2.5V

OUT

0.61

0.60

0.59

Feedback Voltage (V)

0.58

0.57

-40 0 40 80 120 160

Figure 8. Frequency vs. Temperature Figure 9. Feedback Voltage vs. Temperature

VIN=3.3V

Temperature (OC)

2.2

2.0

1.8

1.6

OCP Current Limit (A)

1.4

1.2

-40 0 40 80 120 160

Figure 10. OCP Current Limit vs. Temperature Figure 11. R

Temperature (OC)

VIN=3.3V
V

=0.55V

FB

0.5

0.4

0.3

(Ω)

0.2

DS(ON)-UP

R

0.1

0.0

-40 0 40 80 120 160

Temperature (OC)

DS (ON)_UP

VIN=3.3V
I

=200mA

SW

vs. Temperature

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Typical Performance Characteristics (Continued)

0.32

0.28

0.24

(Ω)

0.20

DS(ON)-Low

R

0.16

0.12

Figure 12. R

VIN=3.3V
I

=200mA

SW

-40 0 40 80 120 160

Temperature (OC)

DS (ON)_LOW

vs. Temperature

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

T ypical Application

R2 R1

V

IN

EN

VIN

AP3407/A-ADJ

C

IN

F

Figure 13. Typical Application of AP3407/A

FB

GND

V

L

SW

H

2.2
C

OUT

F

OUT

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3407/A

Mechanical Dimensions

SOT-23-5 Unit: mm(inch)

2.820(0.111)

0.100(0.004)

0.200(0.008)

0°

8°

0.950(0.037)

Y

T

P

3.020(0.119)

1.800(0.071)

2.000(0.079)

0.300(0.012)

0.400(0.016)

0.200(0.008)

0

0

7

.

0

0

(

.

R

E

F

0

8

2

)

0

.

0

0

.

0

1

.

0

0

(

0

0

9

0

(

0

0

3

.

1

0

)

0

0

.

0

(

0

0

0

.

0

0

5

(

)

6

3

0

.

)

5

.

)

1

5

0

Dec. 2011 Rev. 1. 3 BCD Semiconductor Manufacturing Limited

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BCD Semiconductor Manufacturing Limited

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