AP3431M-G1 [BCDSEMI]
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter; 为1.0MHz ， 2.0A ，同步降压DC- DC转换器
| 型号： | AP3431M-G1 |
| 厂家： | 
BCD SEMICONDUCTOR MANUFACTURING LIMITED |
| 描述： | 1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter |
| 文件： | 总19页 (文件大小：1260K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Features
General Description
•
•
•
•
•
•
High Efficiency Buck Power Converter
Output Current: 2A
The AP3431 is a high efficiency step-down DC-DC
voltage converter. The chip operation is optimized
by peak-current mode architecture with built-in
synchronous power MOS switchers. The oscillator
and timing capacitors are all built-in providing an
internal switching frequency of 1MHz that allows
the use of small surface mount inductors and
capacitors for portable product implementations.
Low RDS(ON) Internal Switches : 120mΩ(VIN=5V)
Adjustable Output Voltage from 0.8V to 0.9×VIN
Wide Operating Voltage Range: 2.7V to 5.5V
Built-in Power Switches for Synchronous
Rectification with High Efficiency
Feedback Voltage: 800mV
Switching Frequency: 1.0MHz
Thermal Shutdown Protection
Internal Soft Start
•
•
•
•
Integrated Soft Start (SS), Under Voltage Lock Out
(UVLO), Thermal Shutdown Detection (TSD) and
short circuit protection are designed to provide
reliable product applications.
Applications
The device is available in adjustable output voltage
•
•
•
•
LCD TV
Set Top Box
Post DC-DC Voltage Regulation
PDA and Notebook Computer
versions ranging from 0.8V to 0.9×VIN when input
voltage range is from 2.7V to 5.5V , and is able to
deliver up to 2.0A.
The AP3431 is available in SOIC-8 package.
SOIC-8
Figure 1. Package Type of AP3431
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
1
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Pin Configuration
M Package
(SOIC-8)
8
7
1
2
3
4
6
5
Figure 2. Pin Configuration of AP3431 (Top View)
Pin Description
Pin Number
Pin Name
Function
1
2
3
VCC
NC
Supply input for the analog circuit
No connection
Ground pin
GND
Feedback pin. Receives the feedback voltage from a resistive
divider connected across the output
Chip enable pin. Active high, internal pull-high with
200kΩ resistor
4
5
FB
EN
6
7
8
PGND
SW
Power switch ground pin
Switch output pin
Power supply input for the MOSFET switch
VIN
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
2
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Functional Block Diagram
Figure 3. Functional Block Diagram of AP3431
Ordering Information
AP3431
A
-
G1:Green
Circuit Type
Package
M: SOIC-8
Blank: Tube
TR: Tape & Reel
Marking ID Packing Type
3431M-G1
3431M-G1
Temperature
Range
Package
Part Number
AP3431M-G1
AP3431MTR-G1
Tube
SOIC-8
-40 to 80°C
Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "G1" in the part number, are RoHS compliant and
green.
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
3
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Absolute Maximum Ratings (Note 1)
Parameter
Symbol
VCC
Value
0 to 6.0
0 to 6.0
-0.3 to VIN+0.3
-0.3 to VIN+0.3
2.9
Unit
V
Supply Input for the Analog Circuit
Power Supply Input for the MOSFET Switch
VIN
V
V
SW Pin Switch Voltage
VSW
VEN
ISW
Enable Voltage
V
A
SW Pin Switch Current
Power Dissipation (on PCB, TA=25°C)
Thermal Resistance (Junction to Ambient, Simulation)
Junction Temperature
PD
1.45
W
θJA
68.63
°C/W
°C
°C
°C
V
TJ
160
Operating Temperature
TOP
TSTG
VHBM
VMM
-40 to 85
-55 to 150
2000
Storage temperature
ESD (Human Body Model)
ESD (Machine Model)
V
200
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.
Recommended Operating Conditions
Parameter
Symbol
VIN
Min
2.7
Max
5.5
Unit
V
Supply Input Voltage
Junction Temperature Range
Ambient Temperature Range
TJ
-40
125
80
°C
TA
-40
°C
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
4
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Electrical Characteristics
VIN=VCC=VEN=5V, VOUT=1.2V, VFB=0.8V, L=2.2µH, CIN=10µF, COUT=22µF, TA=25°C, unless otherwise
specified.
Parameter
Symbol
VIN
Conditions
Min Typ Max Unit
Input Voltage Range
Shutdown Current
Active Current
2.7
5.5
V
IOFF
VEN=0V
VFB = 0.95V
4
µA
µA
ION
460
Regulated1Feedback
Voltage
VFB
∆VOUT/VOUT
IPK
For Adjustable Output Voltage 0.784 0.8 0.816
VIN=2.7V to 5.5V,
V
%
A
Regulated
Output
-3
3
Voltage Accuracy
IOUT=0 to 2.0A
Peak
Inductor
2.9
Current
Oscillator Frequency
PMOSFET RON
fOSC
VIN = 2.7V to 5.5V
VIN = 5V
1.0
120
120
MHz
mΩ
RON(P)
RON(N)
NMOSFET RON
VIN = 5V
mΩ
EN High-level Input
Voltage
EN Low-level Input
Voltage
VEN_H
1.5
90
V
V
VEN_L
IEN
tSS
0.4
EN Input Current
Soft-start Time
2
µA
µs
450
Maximum
Cycle
Duty
DMAX
%
Rising
2.4
2.3
0.1
160
V
V
Under Voltage Lock
Out Threshold
Falling
Hysteresis
Hysteresis=30°C
V
Thermal Shutdown
TSD
°C
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
5
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics
Figure 4. Efficiency vs. Output Current
Figure 5. Efficiency vs. Output Current
Figure 6. 2.5V Load Regulation
Figure 7. 1.8V Load Regulation
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
6
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 8. 2.5V Line Regulation
Figure 9. 1.8V Line Regulation
Figure 10. Efficiency vs. Output Current
Figure 11. Efficiency vs. Output Current
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
7
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 12. 1.2V Load Regulation
Figure 13. 1.0V Load Regulation
Figure 14. 1.2V Line Regulation
Figure 15. 1.0V Line Regulation
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
8
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 16. Efficiency vs. Output Current
Figure 17. Frequency vs. Input Voltage
Figure 18. 3.3V Load Regulation
Figure 19. Temperature vs. Output Current
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
9
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 20. EN Pin Threshold vs. Input Voltage
Figure 21. FB Voltage vs. Output Current
Figure 22. VOUT Ripple
Figure 23. Dynamic Mode
(VIN=5V, VOUT=3.3V, IOUT=500mA)
(Load=200mA to 1200mA, VIN=5V, VOUT=3.3V)
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
10
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 24. VOUT Ripple
Figure 25. Dynamic Mode (Rising)
(VIN=5V, VOUT=3.3V, IOUT=1A)
Figure 26. VOUT Ripple
Figure 27. Dynamic Mode (Falling)
(VIN=5V, VOUT=3.3V, IOUT=2A)
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
11
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 28. EN Pin, Low to High
(VIN=5V, VOUT=3.3V, IOUT=100mA)
Figure 29. Soft Start
(VIN=5V, VOUT=3.3V, IOUT=0A)
Figure 30. EN Pin, Low to High
(VIN=5V, VOUT=3.3V, IOUT=1A)
Figure 31. Soft Start
(VIN=5V, VOUT=3.3V, IOUT=1A)
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
12
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Performance Characteristics (Continued)
Figure 32. EN Pin, High to Low
(VIN=5V, VOUT=3.3V, IOUT=1A)
Figure 33. OTP
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
13
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Application Information
qw
The basic AP3431 application circuit is shown in Figure
35, external components selection is determined by the
load current and is critical with the selection of inductor
and capacitor values.
deviations do not much relieve. The selection of COUT
is determined by the Effective Series Resistance
(ESR) that is required to minimize output voltage
ripple and load step transients, as well as the amount
of bulk capacitor that is necessary to ensure that the
control loop is stable. Loop stability can be also
checked by viewing the load step transient response
as described in the following section. The output
ripple, △VOUT, is determined by:
1. Inductor Selection
For most applications, the value of inductor is chosen
based on the required ripple current with the range of
1µH to 6.8µH.
1
∆VOUT ≤ ∆IL[ESR +
]
1
VOUT
VIN
8× f ×COUT
∆IL =
VOUT (1−
)
f × L
The output ripple is the highest at the maximum input
voltage since △IL increases with input voltage.
The largest ripple current occurs at the highest input
voltage. Having a small ripple current reduces the ESR
loss in the output capacitor and improves the efficiency.
The highest efficiency is realized at low operating
frequency with small ripple current. However, larger
value inductors will be required. A reasonable starting
point for ripple current setting is △IL=40%IMAX . For a
maximum ripple current stays below a specified
value, the inductor should be chosen according to the
following equation:
3. Load Transient
A switching regulator typically takes several cycles to
respond to the load current step. When a load step
occurs, VOUT immediately shifts by an amount equal
to △ILOAD×ESR, where ESR is the effective series
resistance of output capacitor. △ILOAD also begins to
charge or discharge COUT generating a feedback error
signal used by the regulator to return VOUT to its
steady-state value. During the recovery time, VOUT
can be monitored for overshoot or ringing that would
indicate a stability problem.
VOUT
VOUT
L = [
][1−
]
f × ∆IL (MAX )
VIN (MAX )
4. Output Voltage Setting
The output voltage of AP3431 can be adjusted by a
resistive divider according to the following formula:
The DC current rating of the inductor should be at
least equal to the maximum output current plus half
the highest ripple current to prevent inductor core
saturation. For better efficiency,
DC-resistance inductor should be selected.
a
lower
R
R1
R2
VOUT = VREF × (1+ 1 ) = 0.8V × (1+
)
R2
2. Capacitor Selection
The resistive divider senses the fraction of the output
voltage as shown in Figure 34.
The input capacitance, CIN, is needed to filter the
trapezoidal current at the source of the top MOSFET.
To prevent large ripple voltage, a low ESR input
capacitor sized for the maximum RMS current must
be used. The maximum RMS capacitor current is
given by:
VOUT
R1
FB
1
AP3431
R2
[VOUT (VIN −VOUT )]2
IRMS = IOMAX
×
GND
VIN
It indicates a maximum value at VIN=2VOUT, where
RMS=IOUT/2. This simple worse-case condition is
I
commonly used for design because even significant
Figure 34. Setting the Output Voltage
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
14
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Application Information (Continued)
the VIN and this effect will be more serious at higher
input voltages.
5. Short Circuit Protection
When the AP3431 output node is shorted to GND, as
VFB drop under 0.4V, the chip will enter soft-start
mode to protect itself, when short circuit is removed,
and VFB rise over 0.4V, the AP3431 recover back to
normal operation again. If the AP3431 reach OCP
threshold while short circuit, the AP3431 will enter
soft-start cycle until the current under OCP threshold.
6.2 I2R losses are calculated from internal switch
resistance, RSW and external inductor resistance RL.
In continuous mode, the average output current
flowing through the inductor is chopped between
power PMOSFET switch and NMOSFET switch.
Then, the series resistance looking into the SW pin is
a function of both PMOSFET and NMOSFET RDS(ON)
resistance and the duty cycle (D) are as follows:
6. Efficiency Considerations
The efficiency of switching regulator is equal to the
output power divided by the input power times 100%.
It is usually useful to analyze the individual losses to
determine what is limiting efficiency and which
change could produce the largest improvement.
Efficiency can be expressed as:
R
DS(ON) resistance and the duty cycle (D):
RSW = RDS P × D + RDS
×
(
1− D
)
(
ON
)
(
ON N
)
Therefore, to obtain the I2R losses, simply add RSW to
RL and multiply the result by the square of the
average output current.
Efficiency=100%-L1-L2-…..
Other losses including CIN and COUT ESR dissipative
losses and inductor core losses generally account for
less than 2 % of total additional loss.
Where L1, L2, etc. are the individual losses as a
percentage of input power.
Although all dissipative elements in the regulator
produce losses, two major sources usually account for
most of the power losses: VIN quiescent current and
I2R losses. The VIN quiescent current loss dominates
the efficiency loss at very light load currents and the
I2R loss dominates the efficiency loss at medium to
heavy load currents.
7. Thermal Characteristics
In most applications, the part does not dissipate much
heat due to its high efficiency. However, in some
conditions when the part is operating in high ambient
temperature with high RDS(ON) resistance and high
duty cycles, such as in LDO mode, the heat
dissipated may exceed the maximum junction
temperature. To avoid the part from exceeding
maximum junction temperature, the user should do
some thermal analysis. The maximum power
dissipation depends on the layout of PCB, the thermal
resistance of IC package, the rate of surrounding
airflow and the temperature difference between
junction and ambient.
6.1 The VIN quiescent current loss comprises two
parts: the DC bias current as given in the electrical
characteristics and the internal MOSFET switch gate
charge currents. The gate charge current results from
switching the gate capacitance of the internal power
MOSFET switches. Each cycle the gate is switched
from high to low, then to high again, and the packet
of charge, dQ moves from VIN to ground. The
resulting dQ/dt is the current out of VIN that is
typically larger than the internal DC bias current. In
continuous mode,
8. PCB Layout Considerations
When laying out the printed circuit board, the
following checklist should be used to optimize the
performance of AP3431.
IGATE = f × (QP + QN )
Where QP and QN are the gate charge of power
PMOSFET and NMOSFET switches. Both the DC
bias current and gate charge losses are proportional to
1) The power traces, including the GND trace, the SW
trace and the VIN trace should be kept direct, short
and wide.
2) Put the input capacitor as close as possible to the V
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
15
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Application Information (Continued)
-IN and GND pins.
3) The FB pin should be connected directly to the
feedback resistor divider.
4) Keep the switching node, SW, away from the
sensitive FB pin and the node should be kept small
area.
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
16
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Typical Application
R
Note 2: VOUT = VFB × (1+ 1 ) .
R2
Figure 35. Typical Application Circuit of AP3431
Table 1. Component Guide
VOUT(V)
3.3
R1(kΩ)
31.25
21.5
12.5
5
R2(kΩ)
10
L1(µH)
2.2
2.5
10
2.2
1.8
10
2.2
1.2
10
2.2
1.0
3
10
2.2
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
17
Data Sheet
1.0MHz, 2.0A, Synchronous Step Down DC-DC Converter
AP3431
Mechanical Dimensions
SOIC-8
Unit: mm(inch)
4.700(0.185)
0.320(0.013)
1.350(0.053)
1.750(0.069)
5.100(0.201)
0.675(0.027)
0.725(0.029)
D
5.800(0.228)
6.200(0.244)
1.270(0.050)
TYP
D
20:1
0.800(0.031)
0.200(0.008)
0.100(0.004)
0.300(0.012)
0°
8°
1.000(0.039)
3.800(0.150)
4.000(0.157)
0.190(0.007)
0.250(0.010)
1°
5°
0.330(0.013)
0.510(0.020)
0.900(0.035)
06)
.0
0(0
.15
R0
0.450(0.017)
0.800(0.031)
Note: Eject hole, oriented hole and mold mark is optional.
Nov. 2011 Rev. 1. 0
BCD Semiconductor Manufacturing Limited
18
BCD Semiconductor Manufacturing Limited
http://www.bcdsemi.com
- Headquarters
- Wafer Fab
BCD Semiconductor Manufacturing Limited
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd.
No. 1600, Zi Xing Road, Shanghai ZiZhu Science-based Industrial Park, 200241, China
800 Yi Shan Road, Shanghai 200233, China
Tel: +86-21-24162266, Fax: +86-21-24162277
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
REGIONAL SALES OFFICE
Shenzhen Office
Taiwan Office
USA Office
Shanghai SIM-BCD Semiconductor Manufacturing Co., Ltd., Shenzhen Office
BCD Semiconductor (Taiwan) Company Limited
BCD Semiconductor Corp.
Unit A Room 1203, Skyworth Bldg., Gaoxin Ave.1.S., Nanshan District, Shenzhen,
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
30920 Huntwood Ave. Hayward,
China
Taiwan
Tel: +886-2-2656 2808
CA 94544, USA
Tel: +86-755-8826 7951
Tel : +1-510-324-2988
Fax: +86-755-8826 7865
Fax: +886-2-2656 2806
Fax: +1-510-324-2788
相关型号：
AP3432DNTR-G1
Switching Regulator, Current-mode, 3.5A, 1500kHz Switching Freq-Max, PDSO6, DFN-6
DIODES
AP3435MPTR-G1
Switching Regulator, Current-mode, 4.5A, 1000kHz Switching Freq-Max, PDSO8, SOP-8
DIODES
©2020 ICPDF网 联系我们和版权申明