Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Preliminary Datasheet
General Description
The AP3422 contains two independent 1.1MHz fixed
frequency, current mode, PWM synchronous buck
(step-down) DC-DC converters, each of them is
capable of driving a 800mA load with high efficiency,
excellent line and load regulation. Each converter
integrates a main switch and a synchronous switch
without an external Schottky diode. 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 AP3422. This feature greatly simplifies the
design of switch-mode power supplies.
This IC is available in DFN-3×3-10 package.
Features
High Efficiency: up to 95%
•
• Output Current on Each Channel: 800mA
• Input Voltage Range: 2.5V to 5.5V
• Fixed 1.1MHz Frequency
• 100% Duty Cycle in Dropout
• Built-in Short Circuit Protection
• Built-in Thermal Shutdown Function
• Built-in Current Limit Function
• Shutdown Current: <1µA
Applications
• GPS
• WiFi Card
• Portable Media Player
• Digital Still and Video Cameras
DFN-3×3-10
Figure 1. Package Type of AP3422
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Pin Configuration
DN Package
(DFN-3×3-10)
Pin 1 Mark
1
2
3
4
56
Figure 2. Pin Configuration of AP3422 (Top View)
10
9
8
7
Pin Description
Pin Number Pin Name Function
Channel 1 enable control input. Drive EN1 above 1.5V to turn on the
1 EN1
2 FB1
3 VIN2
4 GND2 Ground 2
5 SW2
6 EN2
7 FB2
8 VIN1
9 GND1 Ground 1
10 SW1
Channel 1. Drive EN1 below 0.6V to turn it off (shutdown current <
0.1µA)
Channel 1 feedback input. Connect FB1 to the center point of the external
resistor divider. The feedback voltage is 0.6V
Channel 2 supply input. Bypass to GND with a 10µF or greater ceramic
capacitor
Channel 2 power switch output. Inductor connection to drains of the
internal PFET and NFET switches
Channel 2 Enable Control Input. Drive EN2 above 1.5V to turn on the
Channel 2. Drive EN2 below 0.6V to turn it off (shutdown current <
0.1µA)
Channel 2 feedback input. Connect FB2 to the center point of the external
resistor divider. The feedback voltage is 0.6V
Channel 1 supply input. Bypass to GND with a 10µF or greater ceramic
capacitor
Channel 1 power switch output. Inductor connection to drains of the
internal PFET and NFET switches
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Functional Block Diagram
EN1, EN2 VIN1, VIN2
FB1,
FB2
1, 6
Shutdown
Control
Oscillator
with
0.6V
V
REF
Soft-start
2, 7
Figure 3. Functional Block Diagram of AP3422 (Diagram represents
Slope
Compensation
Error
Amplifier
Current Limit
PWM
Comparator
Detector
Temperature
Current
Sense
Control
Logic
Over
Detector
8, 3
Driver
9, 4
GND1, GND2
½ of the AP3422)
10,5
SW1,
SW2
Ordering Information
AP3422 -
Circuit Type
Package
DN: DFN-3
×3-10
Package
DFN-3×3-10 -40 to 85 ºC AP3422DNTR-G1 BDC Tape & Reel
Temperature
Range
Part Number Marking ID Packing Type
BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS
compliant and green.
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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G1: Green
TR: Tape & Reel
Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Absolute Maximum Ratings (Note 1)
Parameter Symbol Value Unit
Input Voltage V
Feedback Voltage V
EN1, EN2 Pin Voltage V
SW1, SW2 Pin Voltage V
Thermal Resistance
Operating Junction Temperature TJ 150 ºC
Storage Temperature T
Lead Temperature (Soldering, 10sec) T
IN1, VIN2
FB1, VFB2
EN1, VIN2
SW1, VSW2
-0.3 to 6 V
-0.3 to VIN +0.3 V
-0.3 to VIN+0.3 V
-0.3 to VIN+0.3 V
θJA
-65 to 150 ºC
STG
260 ºC
LEAD
50 ºC/W
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 V
Maximum Output Current
Operating Ambient Temperature TA -40 85 ºC
IN1, VIN2
I
OUT1 (MAX),
I
OUT2(MAX
2.5 5.5 V
800 mA
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Electrical Characteristics
V
IN1=VIN2=VEN1=VEN2
full operating temperature range from -40 to 85ºC.
Parameters Symbol Conditions Min Typ Max Unit
Supply Current on Each
Converter
Shutdown Supply Current
on Each Converter
Under Voltage Lockout
Threshold
Under Voltage Lockout
Hysteresis
Feedback Bias Current IFB VFB=0.65V -50 0.5 50 nA
Feedback Voltage VFB I
Maximum Output Current
Switch Current Limit I
Oscillator Frequency f
EN Pin Threshold
EN Pin Input Leakage
Current
Internal PFET On
Resistance
Internal NFET On
Resistance
Maximum Duty Cycle D
Soft-start Time TSS
Thermal Shutdown
Threshold
Thermal Shutdown
Hysteresis
=3.6V, T
=25℃ , unless otherwise specified. Specifications with boldface type apply over
A
I
VFB=0.55V 400 600
CC
VEN=0V, VIN=5.5V 0.01 1
I
SHDN
V
UVLO
V
HUVLO
I
OUT (MAX)
LIM
OSC
V
ENL
V
ENH
I
V
H
Rising Edge 2.27 V
200 mV
OUT
V
IN
V
OUT
VIN=3.6V,
V
OUT
VIN=4.6V,
V
OUT
=100mA
=2.5V,
=0.9V
=1.2V
=3.3V
0.588/
0.582
0.600
800
800
800
0.612/
0.618
VFB=0.55V 0.95 1.25 A
0.8 1.1 1.4 MHz
0.6
1.5
=3.6V -0.1 0.1
EN
IL VEN=0V -0.1 0.1
R
ISW=100mA 0.44 Ω
DSONP
R
ISW=-100mA 0.29 Ω
DSONN
VFB=0.55V 100 %
MAX
=0V to V
V
EN
I
= 50mA
OUT
T
160 ºC
OTSD
T
30 ºC
HYS
IN
220
µA
µA
V
mA
V
µA
µA
µs
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Typical Performance Characteristics
L1=L2=10µ H, C
1.4
IN1=CIN2=COUT1=COUT2
=10µ F, T
=25 ºC , unless otherwise noted.
A
0.7
1.3
1.2
1.1
Frequency (MHz)
1.0
0.9
0.8
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Input Voltage (V)
VIN=3.6V
V
=1.8V
OUT1
I
=0A
OUT
0.6
0.5
0.4
Supply Current (mA)
0.3
0.2
-60 -40 -20 0 20 40 60 80 100 120 140 160
Temperature (oC)
Figure 4. Frequency vs. Input Voltage Figure 5. Supply Current vs. Temperature
2.0
1.8
1.6
1.4
1.2
1.0
0.8
Current Limit (A)
0.6
0.4
0.2
0.0
-60 -40 -20 0 20 40 60 80 100
Temperature (OC)
VIN=3.6V
VFB=0.55V
2.0
1.8
1.6
1.4
1.2
1.0
0.8
Output Voltage (V)
0.6
0.4
0.2
0.0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
VIN=3.6V
V
=1.8V
OUT1
Output Current (A)
VIN=3.6V
VFB=0.55V
Figure 6. Current Limit vs. Temperature Figure 7. Output Voltage vs. Output Current
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Typical Performance Characteristics (Continued)
L1=L2=10µ H, C
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
Normalized Feedback Voltage (%)
-2.0
-60 -40 -20 0 20 40 60 80 100
IN1=CIN2=COUT1=COUT2
Temperature (oC)
=10µ F, T
VIN=3.6V
V
=1.8V
OUT1
=25 ºC , unless otherwise noted.
A
100
90
80
70
Efficiency (%)
60
50
0 200 400 600 800
Output Curren t (mA)
VIN=4.2V
V
=1.8V
OUT1
=1.2V
V
OUT2
Figure 8. Normalized Feedback Voltage vs. Temperature Figure 9. Efficiency vs. Output Current
I
OUT1
500mA
V
OUT1
200mV
I
OUT2
500mA
V
OUT2
200mV
V
SW1
5V
V
OUT1
20mV
V
SW2
5V
V
OUT2
20mV
Time 200µs/div Time 1µs/div
Figure 10. Load Transient (V
=400mA to 800mA, I
I
OUT1
=4.2V, V
IN
=400 to 800mA)
OUT2
OUT1
=1.8V, V
OUT2
=1.2V,
Figure 11. Heavy Load Operation (V
V
OUT1
=1.8V, V
OUT2
=1.2V, I
OUT1=IOUT2
=4.2V,
IN
=800mA)
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Typical Performance Characteristics (Continued)
L1=L2=10µ H, C
IN1=CIN2=COUT1=COUT2
=10µ F, T
=25 ºC , unless otherwise noted.
A
V
EN
2V
V
OUT1
1V
V
OUT2
1V
Time 400µs/div
Figure 12. Start-up from Shutdown (V
V
OUT1
=1.8V, V
=1.2V, VEN=0 to 3.6V, I
OUT2
=4.2V,
IN
OUT1=IOUT2
=400mA)
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
T ypical Application
Figure 13. Typical Application of AP3422
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1.1MHz, 800mA Synchronous DC-DC Buck Converter AP3422
Mechanical Dimensions
DFN-3×3-10 Unit:mm(inch)
Feb. 2013 Rev. 1. 2 BCD Semiconductor Manufacturing Limited
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BCD Semiconductor Manufacturing Limited
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