AP5100
1.2A STEP-DOWN CONVERTER with 1.4MHz SWITCHING
FREQUENCY
AP5100
Document number: DS32130 Rev. 3 - 2
1 of 12
www.diodes.com
April 2012
© Diodes Incorporated
Description
The AP5100 is a current mode step-down converter with a
built-in power MOSFET to enable smallest solution size
power conversion.
With the low series resistance power switch it enables a
constant output current of up to 1.2A over a wide input supply
range. The load and line regulation has excellent response
time over the operating input voltage and temperature range.
The AP5100 is self protected, through a cycle-by-cycle
current limiting algorithm and an on chip thermal protection.
The AP5100 will provide the voltage conversion with a low
count of widely available standard external components.
The AP5100 is available in SOT26 package.
Pin Assignments
1
2
3
7
4
6
EN
GND
IN
FB
SOT26
5
BST
( Top View )
SW
Features
• V
IN
4.75V to 24V
• Load current of up to 1.2A
• Internal Power MOSFET
• Stable with Low ESR Ceramic Output Capacitors
• Up to 90% Efficiency
• 0.1µA Shutdown Mode
• Fixed 1.4MHz Frequency
• Thermal Shutdown
• Cycle-by-Cycle Over Current Protection
• Resistor divider adjustable Output: 0.81V to 15V
• SOT26: Available in “Green” Molding Compound
(No Br, Sb)
• Lead Free Finish/RoHS Compliant (Note 1)
Applications
• Distributed Power Systems
• Battery Charger
• Pre-Regulator for Linear Regulators
• WLED Drivers
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.
Typical Application Circuit
BST
SW
FB
IN
EN
C2
AP5100
R1
R2
D1
GND
V
IN
C3
.L 1
C1
ON
OF F
C6
5
4
1
6
3
V
OUT
Figure 2. Typical Application Circuit
0.6 0.8 1.0 1.200.20.4
LOAD CURRENT (A)
Fig. 1 Efficiency vs. Load Current
EFFI
IEN
(%)
100
90
80
70
60
50
40
V = 12V
L = 3.3µH
IN
V = 5V
OUT
V = 3.3V
OUT
