March 2007

1

KB809

The KB809 is a power supply supervisor that provides

under-voltage monitoring and power-on reset generation in

an industry standard 3-pin SOT package and pinout. The

reset output is asserted at power-on and any time the input

voltage drops below the programmed threshold. It remains

asserted for 180ms (typ.) after the input subsequently rises

back above the threshold boundary. The KB809 has an

active-low reset output. Hysteresis is included to prevent

chattering due to noise, and the KB809 is inherently

immune to brief power supply transients. Typical supply

current is a low 3

µA. For those applications that require a

manual reset function, see the KB811/812. For those appli-

cations that require a longer reset timeout, see the

KB809. (The KB809 is identical to the industry-

standard KB809 with the exception of a shorter reset timout.)

VCC

/RESET

µP

/RESET

VCC

Typical Operating Circuit

• Under-voltage monitor

• Power-on reset generation (180ms Typ)

• Choice of threshold voltages (contact Kingbor regarding

availability)

• Active-low reset output

• No external components required

• Rejects brief input transients

• Industry standard package and pinout

• 3-pin SOT23-3 package

• Monitoring processor, ASIC, or FPGA core and I/O

voltages

• PDAs, hand-held PCs

• Embedded controllers

• Telecommunications systems

• Power supplies

• Wireless / Cellular systems

• Networking hardware

Typical

Nominal

Junction

Part Number

Marking**

Application

Threshold

T

Temperature

Package

Voltage*

Voltage

Range

KB809-293

ADAA C956

3.3V

±5%

2.93

180

–40

°C to +85°C

SOT23-3

Microprocessor Reset circuits

KB809

Kingbor Technology Co.,Ltd

TEL:(86)0755-83095458 FAX:(86)0755-88364052

KB809

General Description

Features

Applications

Ordering Information

Typical Application

Block Diagrams

Typical

Nominal

Junction

Part Number

Marking**

Application

Threshold

T

Temperature

Package

Voltage*

Voltage

Range

KB809-263

AFAA C756

3.3V

±10%

2.63

180

–40

°C to +85°C

SOT23-3

Top Marking:

ADAA & AFAA: To manufacture marking after 2007-3-15

C956 & C756: Before 2007-3-15