Diodes AP3427M User Manual
Dual 1A, 1.5MHZ Synchronous Step-down DC-DC Converter AP3427M
Preliminary Datasheet
General Description
The AP3427M is a high efficiency step-down dual
channel DC-DC voltage converter. The chip
operation is optimized by peak-current mode
architecture with built-in synchronous power
MOSFET switchers. The oscillator and timing
capacitors are all built-in providing an internal
switching frequency of 1.5MHz that allows the use of
small surface mount inductors and capacitors for
portable product implementations.
Integrated Soft Start (SS), Under Voltage Lock Out
(UVLO), Thermal Shutdown Detection (TSD) and
Short Circuit Protection are designed to provide
reliable product applications.
The device is available in adjustable output voltage
ranging from 0.6V to 0.9×V
range is from 2.5V to 5.5V, and is able to deliver up
to 1A.
The AP3427M is available in standard DFN-3×3-10
package.
when input voltage
IN
Features
• High Efficiency Buck Power Converter
• Output Current: 1.0A
• Low R
• Adjustable Output Voltage from 0.6V to 0.9×V
• Wide Operating Voltage Range: 2.5V to 5.5V
• Built-in Power Switches for Synchronous
Rectification with High Efficiency
• Feedback Voltage: 600mV
• 1.5MHz Constant Frequency Operation
• Thermal Shutdown Protection
• Low Drop-out Operation at 100% Duty Cycle
• Input Over Voltage Protection
• No Schottky Diode Required
Internal Switches:200mΩ (VIN=5V)
DS(ON)
Applications
• Post DC-DC Voltage Regulation
• PDA and Notebook Computer
DFN-3×3-10
Figure 1. Package Type of AP3427M
IN
Mar. 2013 Rev. 1.0 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1A, 1.5MHZ Synchronous Step-down DC-DC Converter AP3427M
Pin Configuration
DN Package
（DFN-3×3-10）
Figure 2. Pin Configuration of AP3427M (Top View)
Pin Description
Pin Number Pin Name Function
1 EN1 Enable signal input of channel 1, active high
2 FB1 Feedback voltage of channel 1
3 VIN2 Power supply input of channel 2
4, 9, Exposed Pad GND GND. It should be connected to system ground
5 LX2 Connected from channel 2’s Power MOSFET to inductor
6 EN2 Enable signal input of channel 2, active high
7 FB2 Feedback voltage of channel 2
8 VIN1 Power supply input of channel 1
10 LX1 Connected from channel 1’s Power MOSFET to inductor
Mar. 2013 Rev. 1.0 BCD Semiconductor Manufacturing Limited
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Preliminary Datasheet
Dual 1A, 1.5MHZ Synchronous Step-down DC-DC Converter AP3427M
Functional Block Diagram
FB1/
FB2
2/7
EN 1/EN2
1/6 8/3
Over Current
Comparator
Control
Logic
Reverse Inductor
Current Comparator
Thermal
Shutdown
Current
Sensing
Buffer &
Dead Time
Control
Logic
Bias
Generator
Soft
Start
Bandgap
Reference
Saw-tooth
Generator
-
+
Error
Amplifier
-
+
Oscillator
+
+
-
Modulator
Over Voltage
Comparator
VIN1/VIN2
-
+
4/9
10/5
LX1/
LX2
GND
Figure 3. Functional Block Diagram of AP3427M
Ordering Information
AP3427M -
Circuit Type G1: Green
Package
DN: DFN-3×3-10
Package
DFN-3×3-10
Temperature
Range
-40 to 80°C
Part Number Marking ID
AP3427MDNTR-G1 BFE Tape & Reel
BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant
and green.
Mar. 2013 Rev. 1.0 BCD Semiconductor Manufacturing Limited
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TR: Tape & Reel
Packing
Type
Preliminary Datasheet
Dual 1A, 1.5MHZ Synchronous Step-down DC-DC Converter AP3427M
Absolute Maximum Ratings (Note 1)
Parameter Symbol Value Unit
Supply Input Voltage for the
MOSFET Switch
LX Pin Switch Voltage V
Enable Input Voltage V
LX Pin Switch Current I
Power Dissipation (on PCB,
=25°C)
T
A
Thermal Resistance (Junction to
Ambient, Simulation)
Thermal Resistance (Junction to
Case, Simulation)
Operating Junction Temperature TJ 155
, V
V
IN1
LX1
EN1
LX1
0 to 6.5 V
IN2
, V
-0.3 to VIN+0.3 V
LX2
, V
-0.3 to VIN+0.3 V
EN2
, I
1.8 A
LX2
2.44 W
P
D
θ
JA
θ
JC
41
4.2
°C/W
°C/W
°C
Operating Temperature TOP -40 to 85
Storage Temperature Range T
ESD (Human Body Model) V
ESD (Machine Model)
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.
-55 to 150
STG
2000 V
HBM
200 V
V
MM
°C
°C
Recommended Operating Conditions
Parameter Symbol Min Max Unit
Supply Input Voltage VIN 2.5 5.5 V
Operating Junction Temperature TJ -40 125
Ambient Temperature TA -40 80
°C
°C
Mar. 2013 Rev. 1.0 BCD Semiconductor Manufacturing Limited
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