AP1509
150KHz, 2A PWM BUCK DC/DC CONVERTER
Description
The AP1509 series are monolithic IC designed for a step-
down DC/DC converter, and own the ability of driving a
2A load without additional transistor. It saves board space.
The external shutdown function can be controlled by logic
level and then come into standby mode. The internal
compensation makes feedback control having good line and
load regulation without external design. Regarding protected
function, thermal shutdown is to prevent over temperature
operating from damage, and current limit is against over
current operating of the output switch. If current limit function
occurs and V
FB
is down below 0.5V, the switching frequency
will be reduced. The AP1509 series operates at a switching
frequency
of
150KHz
thus
allow smaller
sized
filter
Pin Assignments
(Top View)
V
IN
Output
FB
SD
1
2
AP1509
3
4
SOP-8L
8
7
6
5
GND
GND
GND
GND
components than what would be needed with lower frequency
switching regulators. Other features include a guaranteed
+4% tolerance on output voltage under specified input voltage
and output load conditions, and +15% on the oscillator
frequency. The output version included fixed 3.3V, 5V, 12V,
and an adjustable type. The chips are available in a standard
8-lead SOP-8 package.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
Output Voltage: 3.3V, 5V, 12V and Adjustable Output
Version
Adjustable Version Output Voltage Range, 1.23V to
18V+4%
150KHz +15% Fixed Switching Frequency
Voltage Mode Non-Synchronous PWM Control
Thermal-Shutdown and Current-Limit Protection
ON/OFF Shutdown Control Input
Operating Voltage can be up to 22V
Output Load Current: 2A
SOP-8L Packages
Low Power Standby Mode
Built-in Switching Transistor On Chip
SOP-8L: Available in “Green” Molding Compound
(No Br, Sb)
Lead Free Finish/ RoHS Compliant (Note 1)
Applications
•
•
•
Simple High-Efficiency Step-Down Regulator
On-Card Switching Regulators
Positive to Negative Converter
Notes:
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at
http://www.diodes.com/products/lead_free.html.
AP1509
Document number: DS31016 Rev. 4 - 2
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June 2010
© Diodes Incorporated
AP1509
150KHz, 2A PWM BUCK DC/DC CONVERTER
Typical Application Circuit
(1) Fixed Type Circuit
FB
12V
DC Input
1
V
IN
4
C
IN
Capacitor
SD
3
AP1509-
33
5
6
7
Output
2
L1
47uH
Inductor
3.3V/2A
Output Load
8
D1
Schottky Diode
Co
Capacitor
GND GND GND GND
(2) Adjustable Type Circuit
R2 1K
12V
DC Input
V
IN
C
IN
Capacitor
1
4
SD
R1 1K
FB
3
L1
39uH
Inductor
D1
Schottky
Diode
Co
Capacitor
2.5V/2A
Output Load
AP1509
5
6
7
2
8
Output
GND GND GND GND
V
OUT
= V
FB
×
(1 +
R1
R2
)
V
FB
= 1.23V
R2 = 1K ~ 3K
(3) Delay Start Circuit
R2 1K
12V
DC Input
FB
3
V
IN
C
DELAY
0.1uF
C
IN
Capacitor
R
DELAY
10K
1
4
SD
R1 1K
L1
39uH
Inductor
D1
Schottky
Diode
Co
Capacitor
2.5V/2A
Output Load
AP1509
5
6
7
2
8
Output
GND GND GND GND
AP1509
Document number: DS31016 Rev. 4 - 2
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June 2010
© Diodes Incorporated
AP1509
150KHz, 2A PWM BUCK DC/DC CONVERTER
Pin Descriptions
Pin Name
V
IN
Output
GND
FB
SD
Description
Operating voltage input
Switching output
Ground
Output voltage feedback control
ON/OFF Shutdown
Functional Block Diagram
SD
V
IN
200mV
Current
Source
bias
1.235V
Reference
2.5V
Regulator
Start
up
220mV
+
Comp
_
Comp
+
FB
Comp
+
AP1509
Document number: DS31016 Rev. 4 - 2
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_
+
Amp
_
Frequecy
compen-
sation
Pre-
driver
150kH
z
OSC.
Thermal
Shutdown
_
2A
Switch
Output
GND
June 2010
© Diodes Incorporated
AP1509
150KHz, 2A PWM BUCK DC/DC CONVERTER
Absolute Maximum Ratings
Symbol
ESD HBM
ESD MM
V
IN
V
SD
V
FB
V
OUT
P
D
T
ST
T
J
Parameter
Human Body Model ESD Protection
Machine Model ESD Protection
Supply Voltage
ON/OFF Pin Input Voltage
Feedback Pin Voltage
Output Voltage to Ground
Power Dissipation
Storage Temperature
Operating Junction Temperature
Rating
2
200
+24
-0.3 to +18
-0.3 to +18
-1
Internally Limited
-65 to +150
-40 to +125
Unit
KV
V
V
V
V
V
W
o
o
C
C
Recommended Operating Conditions
Symbol
I
OUT
V
OP
T
A
Parameter
Output Current
Operating Voltage
Operating Ambient Temperature
Min
0
4.5
-20
Max
2
22
85
Unit
A
V
o
C
AP1509
Document number: DS31016 Rev. 4 - 2
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June 2010
© Diodes Incorporated
AP1509
150KHz, 2A PWM BUCK DC/DC CONVERTER
Electrical Characteristics
Unless otherwise specified, V
IN
= 12V for 3.3V, 5V, adjustable version and V
IN
= 18V for the 12V version. I
LOAD
= 0.5A
Specifications with
boldface type
are for full operating temperature range, the other type are for T
J
= 25ºC.
Symbol
I
FB
F
OSC
F
SCP
V
SAT
DC
I
CL
Parameter
Feedback Bias Current
Oscillator Frequency
Oscillator Frequency of
Short Circuit Protect
Saturation Voltage
Max. Duty Cycle (ON)
Min. Duty Cycle (OFF)
Current Limit
Output
Leakage
Output = -1 Current
Quiescent Current
Standby Quiescent
Current
Output = 0
ON/OFF Pin Logic Input
Threshold Voltage
Conditions
V
FB
= 1.3V
(Adjustable version only)
Min
Typ.
-10
127
110
When current limit occurred
and V
FB
< 0.5V, T
a
= 25
o
C
I
OUT
= 2A
No outside circuit
V
FB
= 0V force driver on
V
FB
= 0V force driver on
V
FB
= 12V force driver off
Peak current
No outside circuit
V
FB
= 0V force driver on
No outside circuit
V
FB
= 12V force driver off
V
IN
= 22V
V
FB
= 12V force driver off
ON/OFF pin = 5V
V
IN
= 22V
Low (regulator ON)
High (regulator OFF)
10
150
30
1.25
100
0
Max
-50
-100
173
173
50
1.4
Unit
nA
KHz
KHz
V
%
A
1.5
3
-200
-5
5
70
-
2.0
1.3
10
150
200
0.6
-
-0.01
-0.1
15
70
-1
o
I
L
I
Q
I
STBY
V
IL
V
IH
I
H
I
L
θ
JA
θ
JC
uA
mA
mA
uA
V
ON/OFF Pin Logic Input
V
LOGIC
= 2.5V (OFF)
Current
ON/OFF Pin Input Current V
LOGIC
= 0.5V (ON)
Junction to
Thermal Resistance
SOP-8L
case
Thermal Resistance
Junction to
SOP-8L
with a copper area of
ambient
approximately 3 in
2
uA
C/W
C/W
o
AP1509
Document number: DS31016 Rev. 4 - 2
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June 2010
© Diodes Incorporated
