BCD AP3211KTR-G1 Schematic [ru]

1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211

Data Sheet

General Description

The AP3211 is a 1.4MHz fixed frequency, current
mode, PWM buck (step-down) DC-DC converter,
capable of driving a 1.5A load with high efficiency,
excellent line and load regulation. The device
integrates N-channel power MOSFET switch with
low on-resistance. Current mode control provides fast
transient response and cycle-by-cycle current limit.

A standard series of inductors are available from
several different manufacturers optimized for use
with the AP3211. This feature greatly simplifies the
design of switch-mode power supplies.

The AP3211 is available in SOT-23-6 package.

Features

• Input Voltage Range: 4.5V to 18V

• Output Voltage Adjustable from 0.81V to 15V

• Fixed 1.4MHz Frequency

• High Efficiency: up to 92%

• Output Current: 1.5A

• Current Mode Control

• Built-in Over Current Protection

• Built-in Thermal Shutdown Function

• Built-in UVLO Function

• Built-in Over Voltage Protection

• Built-in Soft-start

Applications

• LCD TV

• DPF

• Portable DVD

SOT-23-6

Figure 1. Package Type of AP3211

Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211

Pin Configuration

K Package

(SOT-23-6)

Pin 1 Mark

6

BS

1

SW

GND

2

5

IN

FB

34

EN

Figure 2. Pin Configuration of AP3211 (Top View)

Pin Description

Pin Number Pin Name Function

Bootstrap pin. A bootstrap capacitor is connected between the

1 BS

2 GND Ground pin

3 FB

4 EN

5 IN

6 SW

BS pin and SW pin. The voltage across the bootstrap capacitor
drives the internal high-side NMOS switch

Feedback pin. This pin is connected to an external resistor
divider to program the system output voltage. When V
20% of the nominal regulation value of 0.81V, the OVP is
triggered. When V
to realize short circuit protection
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
Supply input pin. A capacitor should be connected between the
IN pin and GND to keep the DC input voltage constant
Power switch output pin. This pin is connected to the inductor
and bootstrap capacitor

＜0.25V, the oscillator frequency is lowered

FB

exceeds

FB

Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211

Functional Block Diagram

Figure 3. Functional Block Diagram of AP3211

Ordering Information

AP3211 -

Circuit Type G1: Green

Package TR: Tape & Reel
K: SOT-23-6

Package

SOT-23-6

Temperature

Range

-40 to 85°C

Part Number Marking ID

AP3211KTR-G1 GCI Tape & Reel

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

Packing

Type

Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211

Absolute Maximum Ratings (Note 1)

Parameter Symbol Value Unit

Input Pin Voltage VIN -0.3 to 20 V
EN Pin Voltage VEN -0.3 to VIN+0.3 V
SW Pin Voltage VSW 21 V
Bootstrap Pin Voltage VBS -0.3 to VSW+6 V
Feedback Pin Voltage VFB -0.3 to 6V V
Thermal Resistance
Operating Junction Temperature TJ 150 ºC
Storage Temperature T

Lead Temperature (Soldering,
10sec)

ESD (Human Body Model) 2000 V
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.

θ

JA

-65 to 150 ºC

STG

260 ºC

T

LEAD

220 ºC/W

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Input Voltage VIN 4.5 18 V
Maximum Output Current I
Operating Ambient Temperature TA -40 85 ºC

OUT (MAX)

1.5 A

Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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Data Sheet

1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211

Electrical Characteristics

VIN=VEN=12V, V

Parameter Symbol Conditions Min Typ Max Unit

Input Voltage VIN 4.5 18 V
Quiescent Current IQ VFB=0.9V 0.8 1.1 mA

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

OUT

Shutdown Supply Current I
Feedback Voltage V
Feedback Over Voltage Threshold V
Feedback Bias Current IFB VFB=0.85V -0.1 0.1
Switch On-resistance R

Switch Leakage Current I
Switch Current Limit I

EN Pin Threshold

Input UVLO Threshold V
Input UVLO Hysteresis V

Oscillator Frequency

Max. Duty Cycle D
Min. Duty Cycle D

VEN=0V 0.1 1.0

SHDN

FB

0.972 V

FBOV

0.785 0.810 0.835 V

μA

μA

ISW=1A

DSON

=18V,

V

IN

LEAK

LIM

V

1.5

ENH

V

0.4

ENL

UVLO

0.2 V

HYS

f

1.1 1.4 1.7 MHz

OSC1

f

Short Circuit 460 kHz

OSC2

VFB=0.6V 90 %

MAX

VFB=0.9V 0 %

MIN

=0V

V

EN

1.8 2.4 A

V

Rising 3.3 3.8 4.3 V

IN

0.35

0.1 10

Ω

μA

V

Minimum On Time tON 100 ns
Thermal Shutdown T
Thermal Shutdown Hysteresis T
Soft-start Time tSS 200

Note 2: R

DSON , tON, TOTSD, THYS

and t

are guaranteed by design.

SS

160 ºC

OTSD

20 ºC

HYS

μs

Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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