Diodes AP3417B User Manual

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Data Sheet

General Description

The AP3417B 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 AP3417B. This feature greatly simplifies the
design of switch-mode power supplies.

The AP3417B is available in SOT-23-5 package.

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

• Built-in Input Over Voltage Protection (IOVP)

IN

Applications

• Set-top Box

• Datacom

• Portable Device

• Smart Phone

Figure 1. Package Type of AP3417B

SOT-23-5

Jan. 2013 Rev. 1. 0 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Pin Configuration

K Package

(SOT-23-5)

EN

GND

SW

Figure 2. Pin Configuration of AP3417B (Top View)

1

2

34

5

FB

VIN

Pin Description

Pin Number Pin Name Function

Control input pin. Forcing this pin above 1.5V enables the IC.

1 EN

2 GND Ground pin

3 SW

4 VIN

5 FB

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

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

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

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Functional Block Diagram

DRIVER

Figure 3. Functional Block Diagram of AP3417B

Ordering Information

AP3417B -

G1: Green

Circuit Type

K: SOT-23-5

Package

SOT-23-5 -40 to 85ºC AP3417BK-ADJTRG1 G2J Tape & Reel

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

Temperature

Range

Part Number

TR: Tape & Reel

ADJ: Adjustable Output

Marking

ID

Packing Type

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

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
Operating Junction Temperature TJ 150 ºC
Storage Temperature T
Lead Temperature (Soldering, 10sec) T
ESD(Machine Model) 200 V
ESD(Human Body Model) 2000 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.

θ

JA

-65 to 150 ºC

STG

260 ºC

LEAD

265 ºC/W

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Input Voltage VIN 2.5 5.5 V
Operating Ambient Temperature TA -40 85 ºC

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Electrical Characteristics

VIN=5V, TA=25ºC, unless otherwise specified.

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

V

STBY

0.588 0.6 0.612 V

REF

V

I

FB_H

=0.65V 62 100

FB

=GND 0.1 1

EN

=1V -0.1 0.1

FB

Feedback Bias Current

I

V

FB_L

PMOSFET RON R

NMOSFET RON R

Switch Current Limit I

ISW=200mA

DS(ON)_ P

ISW=-200mA

DS(ON) _N

LIM

1.5

V

H

=0V -0.1 0.1

FB

=0.55V 1.5 2.0 A

V

FB

EN Pin Threshold

VL 0.4

UVLO Threshold V

UVLO Hysteresis V

Oscillator Frequency f

Max. Duty Cycle D

Min. Duty Cycle D

VIN Rising 2.3

UVLO

0.2

HYS

OSC

MAX

0

MIN

100

µA

µA

µA

0.25

0.2

Ω

Ω

V

V

1.12 1.40 1.68 MHz

%

VSW=0V 0.1

I

SW Leakage Current

SW_H

I

VSW=5V 0.1

SW_L

µA

Soft-start Time tSS 1 ms

Thermal Shutdown T
Thermal Shutdown

Hysteresis
Input OVP Threshold V

Input OVP Hysteresis V

160 ºC

OTSD

T

20 ºC

HYS

V

IOVP

0.5 V

IOVP_HYS

Rising 6.3 V

IN

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Typical Performance Characteristics

100

95

90

85

80

75

70

Efficiency (%)

65

60

55

50

0.00.20.40.60.81.01.2

Figure 4. Efficiency vs. Output Current

Output Current (A)

VIN=5.0V

=1.8V

V

OUT

100

95

90

85

80

75

70

Efficiency (% )

65

60

55

50

0.01 0.1 1

Output Current (A)

VIN=5.0V
V

=1.8V

OUT

Figure 5. Efficiency vs. Output Current

1.81

1.80

1.79

1.78

1.77

1.76

Output Voltage (V)

1.75

1.74

1.73
0 200 400 600 800 1000 1200

Output Current (mA)

1.70

1.65

1.60

1.55

1.50

1.45

1.40

1.35

Frequency (MHz)

1.30

1.25

1.20

2.5 3.0 3.5 4.0 4.5 5.0 5.5

Input Voltage (V)

Figure 6. Output Voltage vs. Output Current

Figure 7. Frequency vs. Input Voltage

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Typical Performance Characteristics (Continued)

1.7

1.6

1.5

1.4

1.3

Frequency (MHz)

1.2

1.1

1.0

-40 -20 0 20 40 60 80 100 120 140

Figure 8. Frequency vs. Temperature

VIN=VEN=5.0V

Temperature (oC)

0.64

0.63

0.62

0.61

0.60

0.59

0.58

Reference Voltage (V)

0.57

0.56

-40 -20 0 20 40 60 80 100 120 140

VIN=5.0V

Temperature (oC)

Figure 9. Reference Voltage vs. Temperature

2.4

2.3

2.2

2.1

2.0

1.9

1.8

1.7

Switch Current Limit (A)

1.6

1.5

1.4

-40 -20 0 20 40 60 80 100 120 140

VIN=5.0V

Temperature (oC)

0.40

0.38

0.36

0.34

0.32

(Ω)

0.30

DS(ON)_UP

0.28

0.26

0.24

PMOS R

0.22

0.20

0.18

-40 -20 0 20 40 60 80 100 120 140

Temperature (oC)

VIN=5.0V
I

=200mA

SW

Figure 10. Switch Current Limit vs. Temperature

Figure 11. R

DS(ON)_UP

vs. Temperature

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Typical Performance Characteristics (Continued)

0.32

0.28

0.24

(Ω)

0.20

DS(ON)_DOWN

0.16

0.12

NMOS R

0.08

0.04

-40 -20 0 20 40 60 80 100 120 140

VIN=5.0V
I

SW

Temperature (oC)

=200mA

Figure 12. R

DS(ON)_DOWN

vs. Temperature Figure 13. Output Ripple (I

100mA/div

V

OUT_AC

5mV/div

V

SW

5V/div

I

L

Time 4ms/div

=0A)

OUT

V

OUT_AC

10mV/div

V

SW

5V/div

I

1A/div

L

Figure 14. Output Ripple (I

Time 400ns/div

=1.2A) Figure 15. Load Transient (I

OUT

V

OUT_AC

200mV/div

V

SW

5V/div

I

OUT

1A/div

Time 200µs/div

=0A to 1.2A)

OUT

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Typical Performance Characteristics (Continued)

V

EN

5V/div

V

SW

5V/div

V

OUT

1V/div

1A/div

I

L

Figure 16. Enable Turn On (I

Time 400µs/div

=1.2A) Figure 17. Enable Turn Off (I

OUT

V

5V/div

V

SW

5V/div

V

OUT

1V/div

1A/div

EN

I

L

Time 200µs/div

=1.2A)

OUT

V

OUT

1V/div

5V/div

1A/div

V

SW

I

L

Figure 18. Short Circuit Protection Figure 19. Short Circuit Protection Recovery

Time 10ms/div

=1.2A) (I

(I

OUT

V

OUT

1V/div

V

SW

5V/div

1A/div

I

L

Time 10ms/div

=1.2A)

OUT

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

Typical Performance Characteristics (Continued)

V

IN

5V/div

V

SW

5V/div

V

OUT

1V/div

1A/div

I

L

Figure 20. Over Voltage Protection Figure 21. Over Voltage Protection Recovery

Time 100ms/div

=1.2A) (I

(I

OUT

V

5V/div

V

SW

5V/div

V

OUT

1V/div

1A/div

IN

I

L

Time 20ms/div

=1.2A)

OUT

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

T ypical Application

Figure 22. Typical Application of AP3417B

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Data Sheet

1.2A, 1.4MHz High Efficiency Synchronous DC-DC Buck Converter AP3417B

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

(

0

0

7

.

R

E

F

0

8

2

)

0

0

.

0

1

.

0

0

(

0

0

9

.

0

(

0

0

3

.

1

0

0

.

0

0

0

(

)

0

0

.

0

(

0

5

0

)

6

3

0

.

)

5

.

)

1

5

0

Jan. 2013 Rev. 1. 0 BCD Semiconductor Manufacturing Limited

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BCD Semiconductor Manufacturing Limited

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