AP1537 Datasheet, PDF (1/7 Pages) Anachip Corp – PWM Control 3A Step-Down Converter

PWM Control 3A Step-Down Converter
AP1537
„ Features
- Input voltage: 3.6V to 18V.
- Output voltage: 0.8V to V_CC.
- Duty ratio: 0% to 100% PWM control
- Oscillation frequency: 500KHz typ.
- Soft-start, Current Limit, Enable function
- Thermal Shutdown function
- Built-in internal SW P-channel MOS
- Low ESR output capacitor (Multi-layer chip
capacitor (MLCC)) application
- SOP-8L Pb-Free Package.
„ Applications
- PC Motherboard
- LCD Monitor
- Graphic Card
- DVD-Video Player
- Telecom Equipment
- ADSL Modem
- Printer and other Peripheral Equipment
- Microprocessor core supply
- Networking power supply
„ Pin Assignments
)
FB 1
EN ²
Comp 3
AP1537
VCC 4
8 ^Vss
7 Vss
6 Output
5 _Output
„ General Description
AP1537 consists of step-down switching regulator
with PWM control. These devices include a reference
voltage source, oscillation circuit, error amplifier,
internal PMOS and etc.
AP1537 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 100%. 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 500KHz 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
mini-package, 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.
„ Pin Descriptions
Name
FB
EN
Comp
VCC
Output
VSS
Pin
Description
1
2
3
4
5、6
7、8
Feedback pin
Power-off pin
H: Normal operation
(Step-down operation)
L: Step-down operation stopped
(All circuits deactivated)
Compensation pin
IC power supply pin
Switch Pin. Connect external
inductor/diode here. Minimize trace
area at this pin to reduce EMI.
GND Pin
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of
this product. No rights under any patent accompany the sale of the product.
Rev. 1. 3 May 09, 2006
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