Download Preliminary Datasheet Features

Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
General Description
Features
The AP3433 is a current mode, PWM synchronous
buck (step-down) DC-DC converter, capable of
driving a 3A load with high efficiency, excellent line
and load regulation.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
The device integrates two N-channel power
MOSFETs with low on-resistance. Current mode
control provides fast transient response and
cycle-by-cycle current limit.
The switching frequency of AP3433 can be
programmable from 300kHz to 2MHz, which allows
small-sized components, such as capacitors and
inductors. A standard series of inductors from several
different manufacturers are available. This feature
greatly simplifies the design of switch-mode power
supplies.
Under voltage lockout is internally set at 2.6V, but
can be increased by programming the threshold with
a resistor network on the enable pin. The output
voltage startup ramp is controlled by the soft-start pin.
An open drain power good signal indicates the output
is within 93% to 107% of its nominal voltage.
AP3433
Input Voltage Range: 2.95V to 5.5V
0.827V Reference Voltage with ±3% Precision
Two 45mΩ(typical) MOSFETs for High
Efficiency at 3A Load
High Efficiency: up to 94%
Output Current: 3A
Programmable Frequency:300kHz to 2MHz
Current Mode Control
Synchronizes to External Clock
Adjustable Soft-start
Soft Start-up into Pre-biased Output
UV and OV Power Good Output
Built-in Over Current Protection
Built-in Thermal Shutdown Function
Programmable UVLO Function
Built-in Over Voltage Protection
Thermally Enhanced 3mm×3mm 16-pin QFN
Applications
•
•
Low-voltage, High-density Power Systems
Point of Load Regulation for Consumer
Applications such as Set Top Boxes, LCD
Displays, CPE Equipment
The AP3433 is available in QFN-3×3-16 package.
QFN-3×3-16
Figure 1. Package Type of AP3433
Jul. 2012
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
1
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Pin Configuration
FN Package
(QFN-3×3-16)
Pin 1 Mark
16
15
14
13
VIN
1
12
SW
VIN
2
11
SW
10
SW
9
SS
GND
3
GND
4
EP
5
6
7
8
Figure 2. Pin Configuration of AP3433 (Top View)
Pin Description
Pin Number
Pin Name
Function
1,2,16
VIN
Supply input pin. A capacitor should be connected between the VIN and GND
pin to keep the DC input voltage constant
3,4
GND
Power ground. This pin should be electrically connected to the power pad under
the IC
5
AGND
Analog ground. This pin should be electrically connected to GND close to the
device
6
FB
7
COMP
8
RT/CLK
9
SS
Soft-start pin. An external capacitor connected to this pin sets the output voltage
rise time. This pin can also be used for tracking
10,11,12
SW
Internal power switch output pin. This pin is connected to the inductor and
bootstrap capacitor
13
BOOT
Bootstrap pin. A bootstrap capacitor is connected between the BOOT pin and SW
pin. The voltage across the bootstrap capacitor drives the internal high-side power
MOSFET
14
PGD
Power good indicator output. Asserts low if output voltage is low due to thermal
shutdown, over-current, over/under-voltage or EN shut down
15
EN
Enable pin, internal pull-up current source. Pull below 1.2V to disable. Float to
enable. Can be used to set the on/off threshold (adjust UVLO) with two additional
resistors
Jul. 2012
Feedback pin. Inverting node of the transconductance error amplifier
Compensation pin. This pin is the output of the transconductance error amplifier
and the input to the current comparator. Connect external compensation elements
to this pin to stabilize the control loop
Resistor timing or external clock input pin
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
2
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Functional Block Diagram
Figure 3. Functional Block Diagram of AP3433
Ordering Information
AP3433
G1: Green
Circuit Type
TR: Tape & Reel
Package
FN: QFN-3×3-16
Package
Temperature
Range
QFN-3×3-16
-40 to 85ºC
Part Number
AP3433FNTR-G1
Marking ID
B1D
Packing Type
Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant
and green.
Jul. 2012
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
3
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Absolute Maximum Ratings (Note 1)
Parameter
Symbol
Value
Unit
VIN Pin Voltage
VIN
-0.3 to 6.5
V
EN Pin Voltage
VEN
-0.3 to 6.5
V
SW Pin Voltage
VSW
-0.3 to VIN+0.3
V
FB Pin Voltage
VFB
-0.3 to 6.5
V
COMP Pin Voltage
VCOMP
-0.3 to 6.5
V
PGD Pin Voltage
VPGD
-0.3 to 6.5
V
VRT/CLK
-0.3 to 6.5
V
SS Pin Voltage
VSS
-0.3 to 6.5
V
Thermal Resistance
(Junction to Ambient)
Thermal Resistance
(Junction to Case)
θJA
70
ºC/W
θJC (BOTTOM)
5
ºC/W
TJ
-40 to 125
ºC
Storage Temperature
TSTG
-65 to 150
ºC
Lead Temperature (Soldering, 10sec)
TLEAD
260
ºC
ESD (Machine Model)
200
V
ESD (Human Body Model)
2000
V
RT/CLK Pin Voltage
Operating Junction Temperature
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
Min
Max
Unit
Input Voltage
VIN
2.95
5.5
V
IOUT(MAX)
3
TA
-40
Maximum Output Current
Operating Ambient Temperature
Jul. 2012
Rev. 1. 1
A
85
ºC
BCD Semiconductor Manufacturing Limited
4
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Electrical Characteristics
VIN=2.95 to 5.5V, TA=25ºC, unless otherwise specified. Specifications with boldface type apply over full
operating temperature range from -40 to 85ºC.
Parameters
Symbol
Conditions
Min
Typ
Max
Unit
5.5
V
360
575
µA
2
5
µA
1.25
1.37
V
SUPPLY VOLTAGE (VIN PIN)
Input Voltage
VIN
Quiescent Current
Shutdown
Current
IQ
Supply
ISHDN
2.95
VFB=0.9V,VIN=5V,
TA=25°C, RT=400kΩ
VEN=0V,TA=25°C
2.95V≤VIN≤5.5V
ENABLE AND UVLO (EN PIN)
Enable Threshold
VEN_H
Rising
VEN_L
Falling
1.16
1.18
Internal Under Voltage
Lockout Threshold
VUVLO
2.6
Internal Under Voltage
Hysteresis
VHYS
150
V
2.8
V
mV
VOLTAGE REFERENCE (FB PIN)
Voltage Reference
VREF
2.95V≤VIN≤5.5V
0.827
0.852
V
VBOOT-SW=5V
45
81
mΩ
VBOOT-SW=2.95V
64
110
mΩ
VIN=5V
42
81
mΩ
VIN=2.95V
59
110
mΩ
0.802
MOSFET
High
Side
On-resistance
Switch
Low
Side
On-resistance
Switch
RON_H
RON_L
CURRENT LIMIT
Current
Threshold
Limit
4.2
ILIMIT
6.6
A
140
°C
20
°C
THERMAL SHUTDOWN
Thermal Shutdown
TTSD
Hysteresis
Jul. 2012
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
5
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Electrical Characteristics (Continued)
VIN=2.95 to 5.5V, TA=25ºC, unless otherwise specified. Specifications with boldface type apply over full
operating temperature range from -40 to 85ºC.
Parameters
Symbol
Conditions
Min
Typ
Max
Unit
300
2000
kHz
300
2000
kHz
600
kHz
TIMING RESISTOR AND EXTERNAL CLOCK (RT/CLK PIN)
Switching Frequency
Range (RT Mode)
Switching Frequency
Range (CLK Mode)
Switching Frequency
fS
400
RT=400kΩ
Minimum CLK Pulse
Width
75
RT/CLK Voltage
RT/CLK
Threshold
RT/CLK
Threshold
500
ns
0.5
RT=400kΩ
High
1.6
Low
0.4
V
2.2
V
0.6
V
VIN=5V
16
Ω
VIN=2.95V
2.2
V
BOOT (BOOT PIN)
BOOT Charge Resistor
RBOOT
BOOT-SW UVLO
SOFT START (SS PIN)
Charge Current
ISS
VSS=0.4
2.2
µA
SS
to
Crossover
VSS
98% Nominal
1.1
V
VFB Falling (Fault)
91
VFB Rising (Good)
93
VFB Rising (Fault)
107
VFB Falling (Good)
105
Reference
POWER GOOD (PGD PIN)
Feedback Threshold
Jul. 2012
VFB_TH
Rev. 1. 1
%VREF
BCD Semiconductor Manufacturing Limited
6
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Typical Performance Characteristics
430
470
425
460
415
450
410
440
Supply Current (µA)
Supply Current (µA)
420
405
400
395
390
385
380
375
430
420
410
400
390
VIN=5V
380
VFB=0.9V
370
365
360
2.7
3.0
3.3
3.6
3.9
4.2
4.5
4.8
5.1
5.4
370
-50
5.7
-25
0
Input Voltage (V)
25
50
75
100
125
150
o
Temperature ( C)
Figure 4. Supply Current vs. Input Voltage
Figure 5. Supply Current vs. Temperature
100
2.60
95
2.55
90
2.50
80
2.45
UVLO Threshold (V)
85
Efficiency (%)
75
70
65
60
55
VOUT=1.8V
50
2.40
2.35
2.30
2.25
45
VIN=3.3V
2.20
40
VIN=5V
2.15
35
Start Switching
Stop Switching
2.10
30
0
300
600
900
1200
1500
1800
2100
2400
2700
-50
3000
0
25
50
75
100
125
150
Temperature ( C)
Figure 6. Efficiency vs. Output Current
Jul. 2012
-25
o
Output Current (mA)
Figure 7.UVLO Threshold vs. Temperature
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
7
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Typical Performance Characteristics (Continued)
1020
0.834
1010
0.832
0.830
990
RT=180k
Reference Voltage (V)
Switching Frequency (kHz)
1000
980
970
960
950
940
930
0.828
0.826
0.824
0.822
0.820
920
0.818
910
900
-50
-25
0
25
50
75
100
125
0.816
-50
150
-25
0
o
25
50
75
100
125
150
Temperature (°C)
Temperature ( C)
Figure 8. Switching Frequency vs. Temperature
Figure 9. Reference Voltage vs. Temperature
800
2000
1900
Switching Frequency (kHz)
Switching Frequency (kHz)
700
600
500
400
300
1800
1700
1600
1500
1400
1300
1200
1100
1000
200
900
100
300
400
500
600
700
800
900
800
80
1000
RT Resistance (kΩ)
120
140
160
180
200
RT Resistance (kΩ)
Figure 10. Switching Frequency vs. RT Resistance
Low Frequency Range
Jul. 2012
100
Figure 11. Switching Frequency vs. RT Resistance
High Frequency Range
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
8
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Typical Performance Characteristics (Continued)
VEN
2V/div
VOUT
1V/div
VSS
2V/div
IL
2A/div
VIN
2V/div
VOUT
1V/div
VSS
2V/div
IL
2A/div
Time
4ms/div
Time
Figure 12. Start up from VIN (VIN=5V, VOUT=1.8V, IOUT=3A)
VOUT(AC)
200mV/div
Figure 13. Disable IC (VIN=5V, VOUT=1.8V, IOUT=3A)
VCLOCK
2V/div
VSW
2V/div
IOUT
2A/div
Time 200µs/div
Time 400ns/div
Figure 14. Load Transient Response
(VIN=5V, VOUT=1.8V, IOUT=0 to 3A)
Jul. 2012
20µs/div
Figure 15. Synchronizing to External Clock
(fCLOCK=2MHz)
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
9
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Typical Performance Characteristics (Continued)
VOUT
1V/div
VOUT
1V/div
VSS
2V/div
VCOMP
0.5V/div
VSS
2V/div
VCOMP
0.5V/div
IL
2A/div
IL
2A/div
Time
4ms/div
Time
Figure 16. Short Circuit Protection
(VIN=5V, VOUT=1.8V, IOUT=3A)
Jul. 2012
4ms/div
Figure 17. Short Circuit Recovery
(VIN=5V, VOUT=1.8V, IOUT=3A)
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
10
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Typical Application
Figure 18. Typical Application of AP3433
Jul. 2012
Rev. 1. 1
BCD Semiconductor Manufacturing Limited
11
www.BDTIC.com/DIODES
Preliminary Datasheet
3A, 2MHz High Performance Synchronous Buck Converter
AP3433
Mechanical Dimensions
QFN-3×3-16
Jul. 2012
Rev. 1. 1
Unit:mm(inch)
BCD Semiconductor Manufacturing Limited
12
www.BDTIC.com/DIODES
BCD Semiconductor Manufacturing Limited
http://www.bcdsemi.com
IMPORTANT
IMPORTANT NOTICE
NOTICE
BCD Semiconductor
Semiconductor Manufacturing
Manufacturing Limited
Limited reserves
reserves the
the right
right to
to make
make changes
changes without
without further
further notice
notice to
to any
any products
products or
or specifispecifiBCD
cations herein.
herein. BCD
BCD Semiconductor
Semiconductor Manufacturing
Manufacturing Limited
Limited does
does not
not assume
assume any
any responsibility
responsibility for
for use
use of
of any
any its
its products
products for
for any
any
cations
particular
purpose, nor
nor does
does BCD
BCD Semiconductor
particular purpose,
Semiconductor Manufacturing
Manufacturing Limited
Limited assume
assume any
any liability
liability arising
arising out
out of
of the
the application
application or
or use
use
of
circuits. BCD
of any
any its
its products
products or
or circuits.
BCD Semiconductor
Semiconductor Manufacturing
Manufacturing Limited
Limited does
does not
not convey
convey any
any license
license under
under its
its patent
patent rights
rights or
or
other
rights of
of others.
others.
other rights
rights nor
nor the
the rights
MAIN
SITE
MAIN SITE
- Headquarters
BCD
Semiconductor Manufacturing Limited
BCD
Semiconductor
Manufacturing Limited
- Wafer
Fab
No.
1600, Zi
Xing Road,
Shanghai ZiZhu
Science-basedLimited
Industrial Park, 200241, China
Shanghai
SIM-BCD
Semiconductor
Manufacturing
Tel:
Fax: +86-21-24162277
800,+86-21-24162266,
Yi Shan Road, Shanghai
200233, China
Tel: +86-21-6485 1491, Fax: +86-21-5450 0008
REGIONAL SALES OFFICE
Shenzhen OfficeSALES OFFICE
REGIONAL
- Wafer
FabSemiconductor Manufacturing Limited
BCD
Shanghai
SIM-BCD
Semiconductor Manufacturing Co., Ltd.
- IC Design
Group
800 Yi
Shan Road,
Shanghai
200233,
China Corporation
Advanced
Analog
Circuits
(Shanghai)
Tel: +86-21-6485
1491,YiFax:
0008200233, China
8F, Zone B, 900,
Shan+86-21-5450
Road, Shanghai
Tel: +86-21-6495 9539, Fax: +86-21-6485 9673
Taiwan Office
Shanghai
Semiconductor Manufacturing Co., Ltd., Shenzhen Office
BCD Taiwan
Semiconductor
Shenzhen SIM-BCD
Office
Office (Taiwan) Company Limited
Unit
A Room
1203, Skyworth
Bldg., Gaoxin
Ave.1.S., Nanshan
Shenzhen,
4F, 298-1,
Guang Road,(Taiwan)
Nei-Hu District,
Taipei,
Shanghai
SIM-BCD
Semiconductor
Manufacturing
Co., Ltd.District,
Shenzhen
Office
BCDRui
Semiconductor
Company
Limited
China
Taiwan
Advanced Analog Circuits (Shanghai) Corporation Shenzhen Office
4F, 298-1, Rui Guang Road, Nei-Hu District, Taipei,
Tel:
+86-755-8826
Tel: +886-2-2656
2808
Room
E, 5F, Noble 7951
Center, No.1006, 3rd Fuzhong Road, Futian District, Shenzhen 518026, China
Taiwan
Fax:
+86-755-88267951
7865
Fax: +886-2-2656
28062808
Tel: +86-755-8826
Tel: +886-2-2656
Fax: +86-755-8826 7865
Fax: +886-2-2656 2806
USA Office
BCD Office
Semiconductor Corp.
USA
30920Semiconductor
Huntwood Ave.Corporation
Hayward,
BCD
CA 94544,
USA Ave. Hayward,
30920
Huntwood
Tel :94544,
+1-510-324-2988
CA
U.S.A
Fax:: +1-510-324-2988
+1-510-324-2788
Tel
Fax: +1-510-324-2788
www.BDTIC.com/DIODES