Diodes AP3408 User Manual
2A, 4MHz High Efficiency Synchronous Buck Converter AP3408
Preliminary Datasheet
General Description
The AP3408 is a current mode, PWM synchronous
buck DC/DC converter, capable of driving a 2A load
with high efficiency, excellent line and load
regulation. It operates in continuous PWM mode.
The AP3408 integrates synchronous P-channel and
N-channel power MOSFET switches with low
on-resistance. It is ideal for portable applications
powered from a single Li-ion battery. 100% duty
cycle and low on-resistance P-channel internal power
MOSFET can maximize the battery life.
The switching frequency of AP3408 can be
programmable from 300kHz to 4MHz, which allows
small-sized components, such as capacitors
inductors
different manufacturers are available. This feature
greatly simplifies the design of switch-mode power
supplies.
The AP3408 is available in DFN-3×3-10 and PSOP-8
packages.
A standard series of inductors from several
.
and
Features
Input Voltage Range: 2.6 to 5.5V
•
• Adjustable Output from 0.8 to 5V
• 0.8V Reference Voltage with ± 2% Precision
• Output Current: 2A
• High Efficiency up to 95%
• Low R
• Programmable Frequency: 300kHz to 4MHz
• Current Mode Control
• Forced Continuous-mode Operation
• 100% Duty Cycle
• Synchronizable Switching Frequency
Power Good Output Voltage Monitoring
•
• Built-in Soft-start
• Built-in Short Circuit Protection
• Built-in Thermal Shutdown Protection
• Built-in Current Limit Function
Internal Switches
DSON
Applications
• Portable Media Player
• Digital Still and Video Cameras
• Notebook
DFN-3×3-10 PSOP-8
Figure 1. Package Types of AP3408
Jan. 2013 Rev. 1. 1
1
BCD Semiconductor Manufacturing Limited
Preliminary Datasheet
2A, 4MHz High Efficiency Synchronous Buck Converter AP3408
Pin Configuration
DN Package MP Package
(DFN-3×3-10) (PSOP-8)
SHDN/ RT
SYNC
GND
SW
PGND
Pin 1 Mark
1
2
Exposed Pad
3
Connected to
4
56
PGND
10
9
8
7
COMP
FB
PGOOD
VDD
PVDD
SHDN/RT
Figure 2. Pin Configuration of AP3408 (Top View)
COMP
1
GND
2
Exposed Pad
Connected to
SW
3
PGND PVDD
4
PGND
8
FB
7
VDD
6
5
Pin Description
Pin Number
DFN-3×3-10 PSOP-8
1 1 SHDN/RT
2 SYNC
3 2 GND
4 3 SW
5 4 PGND
6 5 PVDD
7 6 VDD
8 PGOOD
9 7 FB
10 8 COMP
Jan. 2013 Rev. 1. 1
Pin Name Description
Oscillator resistor input. Connect a resistor to GND from
this pin to set the switching frequency. Forcing this pin to
V
to shutdown the device
DD
External clock synchronization input. The oscillation
frequency can be synchronized to an external oscillation
applied to this pin. When tied to VDD, the internal
oscillator is selected
Signal ground. All small-signal ground, such as the
compensation components and the exposed pad should be
connected to this pin, which in turn connects to PGND at
one point
Internal power switch output. Connect this pin with one
terminal of the inductor
Power ground. Connect this pin as close as possible to CIN
and COUT
Power input supply. Decouple this pin to PGND with a
capacitor
Signal input supply. Decouple this pin to GND with a
capacitor. Normally V
is equal to V
DD
Power Good Indicator. Open-drain logic output that is
pulled to ground when the output voltage is not within ±
12.5% of regulation point
Feedback voltage. This pin is the inverting input of internal
error amplifier. It senses the converter output voltage
through an external resistor divider. The internal reference
voltage is 0.8V, which determines the output voltage
through the resistor divider
Compensation input. This pin is the output of internal error
amplifier. Connect external compensation elements to this
pin to stabilize the control loop
BCD Semiconductor Manufacturing Limited
2
PVDD
Preliminary Datasheet
2A, 4MHz High Efficiency Synchronous Buck Converter AP3408
Functional Block Diagram
SHDN/RT
SYNC
2
SD
1(1)
CS
6(5)
PVDD
COMP
FB
PGOOD
A for DFN-3X3-10
B for PSOP-8
10(8)
9(7)
8
A (B)
0.8V
Oscillator
EA
Clamp
SS
0.4V
0.7V
0.9V
SUM
PWM
Control
Logic
V
REF
7(6)
VDD
Figure 3. Functional Block Diagram of AP3408
OCP
OTPUVLO
Driver
DC
4(3)
SW
5(4)
PGND
3(2)
GND
Jan. 2013 Rev. 1. 1
3
BCD Semiconductor Manufacturing Limited
Preliminary Datasheet
2A, 4MHz High Efficiency Synchronous Buck Converter AP3408
Ordering Information
AP3408 -
G1: Green
Circuit Type
Package
DN: DFN-3×3-10
MP: PSOP-8
TR: Tape & Reel
Blank: Tube
Package
DFN-3×3-10
PSOP-8
Temperature
Range
-40 to 125°C
Part Number Marking ID
Green Green
AP3408DNTR-G1 BFA Tape & Reel
AP3408MP-G1 3408MP-G1 Tube
AP3408MPTR-G1 3408MP-G1 Tape & Reel
Packing
Type
BCD Semiconductor's Pb-free products, as designated with "G1" suffix in the part number, are RoHS compliant
and green.
Absolute Maximum Ratings (Note 1)
Parameter Symbol Value Unit
VDD Pin Voltage VDD -0.3 to 6 V
PVDD Pin Voltage V
-0.3 to 6 V
PVDD
FB Pin Voltage VFB -0.3 to 6 V
COMP Pin Voltage V
-0.3 to 6 V
COMP
SW Pin Voltage VSW -0.3 to VIN+0.3 V
SHDN/RT Pin Voltage V
Thermal Resistance
DFN-3×3-10
PSOP-8 75
SHDN/RT
-0.3 to 6 V
θ
JA
110
ºC/W
Operating Junction Temperature TJ 150 ºC
Storage Temperature T
Lead Temperature (Soldering, 10 sec) T
-65 to 150 ºC
STG
260 ºC
LEAD
ESD (Machine Model) 200 V
ESD (Human Body Model) 2000 V
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.
Jan. 2013 Rev. 1. 1
4
BCD Semiconductor Manufacturing Limited
Loading...