© Semiconductor Components Industries, LLC, 2004

December, 2004 − Rev. 5

1

Publication Order Number:

NCP345/D

NCP345

Overvoltage Protection IC

The NCP345 overvoltage protection circuit (OVP) protects

sensitive electronic circuitry from overvoltage transients and power

supply faults when used in conjunction with an external P−channel

FET. The device is designed to sense an overvoltage condition and

quickly disconnect the input voltage supply from the load before any

damage can occur. The OVP consists of a precise voltage reference, a

comparator with hysteresis, control logic, and a MOSFET gate driver.

The OVP is designed on a robust BiCMOS process and is intended to

withstand voltage transients up to 30 V.

The device is optimized for applications that have an external

AC/DC adapter or car accessory charger to power the product and/or

recharge the internal batteries. The nominal overvoltage threshold is

6.85 V so it is suitable for single cell Li−Ion applications as well as 3/4

cell NiCD/NiMH applications.

Features

Typical Applications

−

+

OUT

IN

GND

CNTRL

+

Logic

FET

Driver

Undervoltage

Lock Out

LOAD

AC/DC Adapter or

Accessory Charger

C1

Schottky

Diode

Microprocessor port

P−CH

Figure 1. Simplified Application Diagram

NCP345

Note: This device contains 89 active transistors

THIN SOT−23−5

SN SUFFIX

CASE 483

1

5

PIN CONNECTIONS &

MARKING DIAGRAM

1

3

IN

OUT

2

GND

CNTRL

4

VCC

5

(Top View)

Device

Package

ORDERING INFORMATION

NCP345SNT1

SOT−23−5

3000 / Tape &

Reel

(7 inch Reel)

Y

= Year

W

= Work Week

NCP345SNT1G

SOT−23−5

(Pb−Free)

†For information on tape and reel specifications,

including part orientation and tape sizes, please

refer to our Tape and Reel Packaging Specifications

Brochure, BRD8011/D.

http://onsemi.com