Diodes AP3409A User Manual
AP3409/A
Document number: DS36789 Rev. 2 - 2
1 of 11
www.diodes.com
January 2014
© Diodes Incorporated
AP3409/A
A Product Line of
Diodes Incorporated
Description
The AP3409/A is a current mode, PWM synchronous buck DC/DC
converter, capable of driving a 3A load with high efficiency, excellent
line and load regulation. It operates in continuous PWM mode.
The AP3409/A 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 AP3409/A can be programmable from
300kHz to 4MHz, 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.
The AP3409/A is available in U-DFN3030-10 package.
Features
Input Voltage Range: 2.6V to 5.5V
Adjustable Output from 0.8V to 5V
0.8V Reference Voltage with ± 2% Precision
Output Current: 3A
High Efficiency up to 95%
Low R
DSON
Internal Switches
Programmable Frequency: 300kHz to 4MHz
Current Mode Control
Forced Continuous-mode Operation
100% Duty Cycle
Built-in Soft-start
Built-in Short Circuit Protection
Built-in Thermal Shutdown Protection
Built-in Current Limit Function
PGOOD Output Voltage Monitoring (For AP3409A)
U-DFN3030-10 package
Totally Lead-free & Fully RoHS Compliant (Note 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Pin Assignments
(Top View)
U-DFN3030-10 (DN Package)
For AP3409
(Top View)
U-DFN3030-10 (DN Package)
For AP3409A
Applications
Portable Media Player
Digital Still and Video Cameras
Notebook
SHDN/RT
GND
SW
SW
PGND
COMP
FB
VDD
PVDD
PVDD
Pin 1 Mark
1
2
3
4
5 6
7
8
9
10
Exposed Pad
Connected to
PGND
SHDN/RT
GND
SW
SW
PGND
COMP
FB
PGOOD
VDD
PVDD
Pin 1 Mark
1
2
3
4
5 6
7
8
9
10
Exposed Pad
Connected to
PGND
Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green"
and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
3A, 4MHz HIGH EFFICIENCY SYNCHRONOUS BUCK CONVERTER
AP3409/A
Document number: DS36789 Rev. 2 - 2
2 of 11
www.diodes.com
January 2014
© Diodes Incorporated
AP3409/A
A Product Line of
Diodes Incorporated
AP3409
SHDN/RT
GND
SW
PGND
COMP
FB
VDD
PVDD
V
IN
5V
R
OSC
330k
L1 2.0mH
C
IN
22mF
C1
22pF
C
OUT
22mF ×2
R1
510k
R2 240k
C
COMP
1000pF
R
COMP
30k
V
OUT
2.5V/3A
AP3409A
SHDN/RT
GND
SW
PGND
COMP
FB
PGOOD
VDD
(PVDD)
V
IN
5V
R
OSC
330k
L1 2.0mH
C
IN
22mF
C1
22pF
C
OUT
22mF ×2
R1
510k
R2 240k
C
COMP
1000pF
R
COMP
30k
V
OUT
2.5V/3A
R4
100k
2
)21(RRRV
V
FB
OUT
Typical Applications Circuit (Note 4)
Notes 4:
Typical Application of AP3409
Typical Application of AP3409A
AP3409/A
Document number: DS36789 Rev. 2 - 2
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www.diodes.com
January 2014
© Diodes Incorporated
AP3409/A
A Product Line of
Diodes Incorporated
Pin Number
Pin Name
Function
AP3409
AP3409A
1
1
SHDN/RT
Oscillator resistor input. Connect a resistor to GND from this pin to set the
switching frequency. Forcing this pin to VDD to shutdown the device
2
2
GND
Signal ground. All small-signal ground, such as the compensation
components and exposed pad should be connected to this, which in turn
connects to PGND at one point
3, 4
3, 4
SW
Internal power switch output. Connect this pin with one terminal of the
inductor
5
5
PGND
Power ground. Connect this pin as close as possible to CIN and C
OUT
6, 7
6
PVDD
Power Input Supply. Decouple this pin to PGND with a capacitor
8
7
VDD
Signal input supply. Decouple this pin to GND with a capacitor. Normally
VDD is equal to V
PVDD
–
8
PGOOD
Power good indicator. This pin is open-drain logic output that is pulled to
ground when the output voltage is not within ±12.5% of regulation point
9
9
FB
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
10
10
COMP
Compensation input. This pin is the output of internal error amplifier.
Connect external compensation elements to this pin to stabilize the
control loop
SD
Oscillator
SUM
CS
0.8V
EA
OCP
Driver
Control
Logic
OTPUVLO
V
REF
0.4V
SHDN/RT
PVDD
SW
GND
PGND
VDD
FB
COMP
1
2
10
3, 4
5
6, 7
8
9
PWM
Clamp
SS
DC
Pin Descriptions
Functional Block Diagram
Functional Block Diagram of AP3409
AP3409/A
Document number: DS36789 Rev. 2 - 2
4 of 11
www.diodes.com
January 2014
© Diodes Incorporated
AP3409/A
A Product Line of
Diodes Incorporated
SD
Oscillator
SUM
CS
0.8V
EA
OCP
Driver
Control
Logic
OTPUVLO
0.4V
SHDN/RT
PVDD
SW
GND
PGND
VDD
FB
COMP
1
2
10
3, 4
5
6
7
9
PWM
Clamp
SS
DC
8
PGOOD
V
REF
0.725V
0.9V
Symbol
Parameter
Rating
Unit
VDD
VDD Pin Voltage
-0.3 to 6
V
V
PVDD
PVDD Pin Voltage
-0.3 to 6
V
VFB
FB Pin Voltage
-0.3 to 6
V
V
COMP
COMP Pin Voltage
-0.3 to 6
V
VSW
SW Pin Voltage
-0.3 to VIN+0.3
V
VRT
SHDN/RT Pin Voltage
-0.3 to 6
V
θ
JA
Thermal Resistance (Junction to Ambient)
110
ºC/W
θ
JC
Thermal Resistance (Junction to Case)
3
ºC/W
TJ
Operating Junction Temperature
+150
ºC
T
STG
Storage Temperature
-65 to +150
ºC
T
LEAD
Lead Temperature (Soldering, 10 sec)
+260
ºC
–
ESD (Machine Model)
200 V –
ESD (Human Body Model)
2000
V
Functional Block Diagram (Cont.)
Absolute Maximum Ratings (Note 5)
Note 5: 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.
Functional Block Diagram of AP3409A
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