Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
1
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 suppl i es.
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
Figure 1. Package Type of AP3211
SOT-23-6
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
2
Pin Configuration
K Package
(SOT-23-6)
Figure 2. Pin Configuration of AP3211 (Top View)
Pin Description
Pin Number Pin Name Function
1 BS
Bootstrap pin. A bootstrap capacitor is connected between the
BS pin and SW pin. The voltage across the bootstrap capacitor
drives the internal high-side NMOS switch
2 GND Ground pin
3 FB
Feedback pin. This pin is connected to an external resistor
divider to program the system output voltage. When VFB exceeds
20% of the nominal regulation value of 0.81V, the OVP is
triggered. When VFB＜0.25V, the oscillator frequency is lowered
to realize short circuit protection
4 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
5 IN
Supply input pin. A capacitor should be connected between the
IN pin and GND to keep the DC input voltage constant
6 SW
Power switch output pin. This pin is connected to the inductor
and bootstrap capacitor
BS 1
2
34
5
Pin 1 Mark
6
GND
FB
SW
IN
EN
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
3
Functional Block Diagram
Figure 3. Functional Block Dia gram of AP32 11
Ordering Information
AP3211 -
Circuit Type G1: Green
Package TR: Tape & Reel
K: SOT-23-6
Package Temperature
Range Part Number Marking ID Packing
Type
SOT-23-6 -40 to 85°C 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.
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
4
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 Pi n Vol t a ge VBS -0.3 to VSW+6 V
Feedback Pin Voltage VFB -0.3 to 6V V
Thermal Resistance θJA 220 ºC/W
Operating Junction Temperature TJ 150 ºC
Sto rage Temperature TSTG -65 to 150 ºC
Lead Temperature (Soldering,
10sec) TLEAD 260 ºC
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 p eriods may affect device reliability.
Recommended Operating Conditions
Parameter Symbol Min Max Unit
Input Voltage VIN 4.5 18 V
Maximum Output Current IOUT (MAX) 1.5 A
Operating Ambient T emperature TA -40 85 ºC
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
5
Electrical Characteristics
VIN=VEN=12V, VOUT=3.3V, TA=25ºC, unless otherwise specified.
Parameter Symbol Conditions Min Typ Max Unit
Input Voltage VIN 4.5 18 V
Quiescent Current IQ V
FB=0.9V 0.8 1.1 mA
Shutdown Supply Current ISHDN V
EN=0V 0.1 1.0
μA
Feedback Voltage VFB 0.785 0.810 0.835 V
Feedback Over Voltage Threshold VFBOV 0.972 V
Feedback Bias Current IFB V
FB=0.85V -0.1 0.1
μA
Switch On-resistance RDSON I
SW=1A
0.35 Ω
Switch Leakage Current ILEAK VIN=18V,
VEN=0V 0.1 10
μA
Switch Current Limit ILIM 1.8 2.4 A
EN Pin Threshold VENH 1.5 V
VENL 0.4
Input UVLO Threshold VUVLO VIN Rising 3.3 3.8 4.3 V
Input UVLO Hysteresis VHYS 0.2 V
Oscillator Frequency fOSC1 1.1 1.4 1.7 MHz
fOSC2 Short Circuit 460 kHz
Max. Duty Cycle DMAX V
FB=0.6V 90 %
Min. Duty Cycle DMIN V
FB=0.9V 0 %
Minimum On Time tON 100 ns
Thermal Shutdown TOTSD 160 ºC
Thermal Shutdown Hysteresis THYS 20 ºC
Soft-start T ime tSS 200 μs
Note 2: RDSON , tON, TOTSD, THYS and tSS are guaranteed by desi gn .
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
6
Typical Performance Characteristics
TA=25ºC, VIN=12V, VEN=5V, VOUT=3.3V, unless otherwise noted.
Figure 4. Efficiency vs. Output Current Figure 5. Quiescent Current vs. Temperature
Figure 6. Feedback Voltage vs.Temperature Figure 7. Output Voltage vs. Output Current
0.01 0.1 0.5 1 2
0
10
20
30
40
50
60
70
80
90
100
Efficiency (%)
Output Curr en t ( A)
VIN=12V,VOUT=3.3V
VIN=12V,VOUT=5V
-60 -40 -20 0 20 40 60 80 100 120 140 160
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
Quiescent Current (mA)
Temperature (oC)
VIN=12V
VFB=0.9V
VEN=5V
-60 -40 -20 0 20 40 60 80 100 120 140 160
0.40
0.48
0.56
0.64
0.72
0.80
0.88
0.96
Feedba ck Vo ltage (V)
Temperature (oC)
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
VIN=12V, VOUT=3.3V
Output Voltage (V)
Output Current (A)
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
7
Typical Performance Characteristics (Continued)
TA=25ºC, VIN=12V, VEN=5V, VOUT=3.3V, unless otherwise noted.
Figure 8. Output Voltage vs. Input Voltage Figure 9. Maximum Output Current vs. Input Voltage
Figure 10. Output Ripple (IOUT=1.5A) Figure 11.Load Transient (IOUT=1 to 1.5A)
4 6 8 101214161820
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
Output Voltage (V)
Input Voltage (V)
IOUT=1.2A
IOUT=1.5A
4 6 8 101214161820
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
Maximum Output Current (A)
Input V ol tag e ( V )
VOUT=3.3V
VOUT (AC)
20mV/div
VSW
5V/div
IL
1A/div
VIN
10V/div
VOUT (AC)
100mV/div
IL
1A/div
Time (400ns/div) Time (100μs/div)
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
8
Typical Performance Characteristics (Continued)
TA=25ºC, VIN=12V, VEN=5V, VOUT=3.3V, unless otherwise noted.
Figure 12. Enable Turn-on Characteristic Figure 13. Enable Turn-off Characteristic
(Resistance Load, RLOAD=2.6Ω) (Resistance Load, RLOAD=2.6Ω)
F igure 14. Short Circuit Protection (IOUT=1.5A) Figure 15.Short Circuit Recovery (RLOAD=2.6Ω)
Time (100μs/div)
VEN
3.8V/div
VOUT
1V/div
VSW
5V/div
IL
1A/div
VEN
3.4V/div
VOUT
1V/div
VSW
5V/div
IL
1A/div
Time (10μs/div)
VFB
1V/div
VOUT
2V/div
IL
1A/div
VSW
10V/div
Time (400μs/div) Time (400μs/div)
VOUT
2V/div
VFB
1V/div
IL
1A/div
VSW
10V/div
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
9
Typical Performance Characteristics (Continued)
TA=25ºC, VIN=12V, VEN=5V, VOUT=3.3V, unless otherwise noted.
Figure 16. Over Voltage Protection (IOUT=1.5A) Figure 17. Over Voltag e Recovery (IOUT=1.5A)
Time (20μs/div)
VFB
500mV/div
VOUT
2V/div
IL
1A/div
VSW
10V/div
VFB
500mV/div
VOUT
2V/div
IL
1A/div
VSW
10V/div
Time (200μs/div)
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
10
Typical Application
Figure 18. Typical Application Circuit of AP3211
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
11
Mechanical Dimensions
SOT-23-6 Unit: mm(inch)
2.820(0.111)
3.100(0.122)
0.950(0.037)TYP
1.800(0.071)
2.000(0.079)
0.300(0.012)
0.500(0.020)
0.700(0.028)REF
0.100(0.004)
0.200(0.008)
0°
8°
0.200(0.008)
0.300(0.012)
0.600(0.024)
0.000(0.000)
0.150(0.006)
0.900(0.035)
1.300(0.051) 1.450(0.057)
MAX
123
4
5
6
Pin 1 Mark
Data Sheet
1.4MHz, 1.5A ASYNCHRONOUS DC-DC BUCK CONVERTER AP3211
Apr. 2013 Rev. 1. 4 BCD Semiconductor Manufacturing Limited
12
Mounting Pad Layout
SOT-23-6
Dimensions Z
(mm)/(inch) G
(mm)/(inch) X
(mm)/(inch) Y
(mm)/(inch) E
(mm)/(inch)
Value 3.600/0.142 1.600/0.063 0.700/0.028 1.000/0.039 0.950/0.037
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility fo r use of any its products for any
particular purpose, nor does BCD Semiconductor Man ufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Limited
800, Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
BCD Semiconductor Manufacturing Limited
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd. Shenzhen Office
Advanced Analog Circuits (Shanghai) Corporation Shenzhen Office
Room E, 5F, Noble Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China
Tel: +86-755-8826 7951
Fax: +86-755-8826 7865
Taiwan Office
BCD Semiconductor (Taiwan) Company Limited
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Taiwan
Tel: +886-2-2656 2808
Fax: +886-2-2656 2806
USA Office
BCD Semiconductor Corporation
30920 Huntwood Ave. Hayward,
CA 94544, U.S.A
Tel : +1-510-324-2988
Fax: +1-510-324-2788
- IC Design Group
Advanced Analog Circuits (Shanghai) Corporation
8F, Zone B, 900, Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6495 9539, Fax: +86-21-6485 9673
BCD Semiconductor Manufacturing Limited
http://www.bcdsemi.com
BCD Semiconductor Manufacturing Limited
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any
particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.
800 Yi Shan Road, Shanghai 200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd., Shenzhen Office
Unit A Room 1203, Skyworth Bldg., Gaoxin Ave.1.S., Nanshan District, Shenzhen,
China
Tel: +86-755-8826 7951
Fax: +86-755-8826 7865
Taiwan Office
BCD Semiconductor (Taiwan) Company Limited
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Taiwan
Tel: +886-2-2656 2808
Fax: +886-2-2656 2806
USA Office
BCD Semiconductor Corp.
30920 Huntwood Ave. Hayward,
CA 94544, USA
Tel : +1-510-324-2988
Fax: +1-510-324-2788
- Headquarters
BCD Semiconductor Manufacturing Limited
No. 1600, Zi Xing Road, Shanghai ZiZhu Science-based Industrial Park, 200241, China
Tel: +86-21-24162266, Fax: +86-21-24162277
IMPORTANT NOTICE
BCD Semiconductor Manufacturing Limited reserves the right to make changes without further notice to any products or specifi-
cations herein. BCD Semiconductor Manufacturing Limited does not assume any responsibility for use of any its products for any
particular purpose, nor does BCD Semiconductor Manufacturing Limited assume any liability arising out of the application or use
of any its products or circuits. BCD Semiconductor Manufacturing Limited does not convey any license under its patent rights or
other rights nor the rights of others.
- Wafer Fab
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.
800 Yishan Road, Shanghai 200233, China
Tel: +021-6485-1491, Fax: +86-021-5450-0008
MAIN SITE
REGIONAL SALES OFFICE
Shenzhen Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd., Shenzhen Office
Unit A Room 1203,Skyworth Bldg., Gaoxin Ave.1.S., Nanshan District
Shenzhen 518057, China
Tel: +86-0755-8660-4900, Fax: +86-0755-8660-4958
Taiwan Office (Taipei)
BCD Semiconductor (Taiwan) Company Limited
3F, No.17, Lane 171, Sec. 2, Jiu-Zong Rd., Nei-Hu Dist., Taipei(114), Taiwan, R.O.C
Tel: +886-2-2656 2808
Fax: +886-2-2656-2806/26562950
Taiwan Office (Hsinchu)
BCD Semiconductor (Taiwan) Company Limited
8F, No.176, Sec. 2, Gong-Dao 5th Road, East District
HsinChu City 300, Taiwan, R.O.C
Tel: +886-3-5160181, Fax: +886-3-5160181
- Headquarters
BCD (Shanghai) Micro-electronics Limited
No. 1600, Zi Xing Road, Shanghai ZiZhu Science-based Industrial Park, 200241, P. R.C.
Tel: +86-021-2416-2266, Fax: +86-021-2416-2277
USA Office
BCD Semiconductor Corp.
48460 Kato Road, Fremont, CA 94538, USA
Tel: +1-510-668-1950
Fax: +1-510-668-1990
Korea Office
BCD Semiconductor Limited Korea office.
Room 101-1112, Digital-Empire II, 486 Sin-dong,
Yeongtong-Gu, Suwon-city, Gyeonggi-do, Korea
Tel: +82-31-695-8430
