Diodes AP3422 User Manual
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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