http://www.belling.com.cn

- 1-

8/8/2006

BL8501

Step down DC/DC controller

OUTLINE

The BL8501 is a CMOS-based PWM step-down DC-DC Converter controller. The device can

offer the following advantages: lower supply current and wider operating input-voltage range.

The BL8501 consists of an oscillator, a PWM control circuit, a reference voltage unit, an error

amplifier, a soft-start circuit, a protection circuit, a PWM/VFM alternative circuit, a chip enable

circuit, and detecting input voltage circuit. A low ripple, high efficiency step-down DC-DC

converter can be easily composed of this IC with only several external components, or a

power-transistor, an inductor, a diode and capacitors. Output Voltage can be adjusted with

external resistors.

FEATURES

Range of input Voltage: 3.5V~12V

Built-in Soft-start Function and Protection Function (Reset type protection)

Oscillation Frequency: 500KHz

High efficiency: 90%

High Accuracy Output Voltage:

2.0%

Low Temperature-Drift Coefficient of Output Voltage: Typ:

100ppm/°C

Operating Temperature Range: -20 ~85

APPLICATIONS

Power source for hand-held communication equipment, cameras, video instruments

such as VCRs, camcorders.

Power source for battery-powered equipment.

Power source for household electrical appliances.

PIN CONFIGURATION

SOT-23-5L

PIN DESCRIPTION

DETAILED DESCRIPTION

Pin No.

Symbol

Description

1

CE

Chip Enable Pin (Active with “H”)

2

GND

Ground Pin

3

V

FB

Pin for Feedback Voltage

4

EXT

External Transistor Drive Pin (CMOS Output)

5

V

IN

Power Supply Pin