AP1538 Datasheet, PDF (1/14 Pages) Diodes Incorporated – 18V 3A 300KHz BUCK CONVERTER

AP1538
18V 3A 300KHz BUCK CONVERTER
Features
• Input voltage : 3.6V to 18V
• Output voltage : 0.8V to V_CC
• Output current : up to 3A
• Duty ratio: 0% to 99% PWM control
• Oscillation frequency: 300KHz typical
• Soft-start like, Current limit and Enable function
• Thermal Shutdown function
• Built-in internal SW P-channel MOS
• SOP-8L and SOP-8L-DEP: Available in “Green”
Molding Compound (No Br, Sb)
• Lead Free Finish / RoHS Compliant (Note 1)
Applications
• PC Motherboard
• LCD Monitor
• Graphic Card
• DVD-Video Player
• Telecom Equipment
• ADSL Modem
• Printer and other Peripheral Equipment
• Microprocessor core supply
General Description
AP1538 consists of step-down switching regulator with PWM
control. These devices include a reference voltage source,
oscillation circuit, error amplifier, internal PMOS.
AP1538 provides low-ripple power, high efficiency, and excellent
transient characteristics. The PWM control circuit is able to vary
the duty ratio linearly from 0 up to 99%. This converter also
contains an error amplifier circuit as well as a soft-start circuit that
prevents overshoot at startup. An enable function, an over
current protect function and a short circuit protect function are built
inside, and when OCP or SCP happens, the operation frequency
will be reduced from 300KHz to 50KHz. Also, an internal
compensation block is built in to minimum external component
count.
With the addition of an internal P-channel Power MOS, a coil,
capacitors, and a diode connected externally, these ICs can
function as step-down switching regulators. They serve as ideal
power supply units for portable devices when coupled with the
SOP-8L and SOP-8L-DEP mini-packages, providing such
outstanding features as low current consumption. Since this
converter can accommodate an input voltage up to 18V, it is also
suitable for the operation via an AC adapter.
Ordering Information
AP 1538 XXX G - X
Package
S : SOP-8L
SDP : SOP-8L-DEP
Lead Free
G : Green
Packing
U : Tube
13 : Tape & Reel
Device
AP1538SG-U
AP1538SG-13
AP1538SDPG-U
AP1538SDPG-13
Package
Code
S
S
SDP
SDP
Packaging
(Note 2)
SOP-8L
SOP-8L
SOP-8L-DEP
SOP-8L-DEP
Tube
Quantity Part Number
Suffix
100
-U
NA
NA
100
-U
NA
NA
13” Tape and Reel
Quantity
Part Number
Suffix
NA
NA
2500/Tape & Reel
-13
NA
NA
2500/Tape & Reel
-13
Notes:
1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes.
2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
AP1538 Rev. 2
1 of 14
www.diodes.com
JUNE 2008
© Diodes Incorporated