Diodes AP1509 User Manual
Ap1509
AP1509
150KHz, 2A PWM BUCK DC/DC CONVERTER
AP1509
Document number: DS31016 Rev. 4 - 2
1 of 13
June 2010
© Diodes Incorporated
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
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.
Pin Assignments
(Top View)
1
2
3
4
8
7
6
5
V
IN
GND
FB
AP1509
GND
Output
GND
GND
SD
SOP-8L
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