July 2005

1

M9999-071305

MIC809-5

Micrel

MIC809-5

Microprocessor Reset Circuit

General Description

The MIC809-5 is a power supply supervisor that provides

under-voltage monitoring and power-on reset generation in

an industry standard 3-pin SOT package and SC-70 pack-

age. The reset output is asserted at power-on and any time

the input voltage drops below the programmed threshold. It

remains asserted for 30ms (min.) after the input subsequently

rises back above the threshold boundary. The MIC809-5 has

an active-low reset output.

The MIC809-5 is inherently immune to brief power supply

transients. Typical supply current is a low 5µA. For those

applications that require a manual reset function, see the

MIC811/812. For those applications that require a longer

reset timeout, see the MIC809/810. (The MIC809-5 is identi-

cal to the industry-standard MIC809 with the exception of a

shorter reset timeout).

Typical Application

VCC

/RESET

µP

/RESET

MIC809-5

VCC

Features

• Under-voltage monitor

• Power-on reset generation (30ms minimum)

• Choice of threshold voltages

• Active-low reset output

• No external components required

• Rejects brief input transients

• Industry standard package and pinout

• 3-pin IttyBitty™ SOT23-3 package and SC-70 package

Applications

• PDAs, hand-held PCs

• Embedded controllers

• Telecommunications systems

• Power supplies

• Wireless/cellular systems

• Networking hardware

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

Ordering Information

Typical

Nominal

Application

Threshold

Operating

Part Number

Marking

Voltage*

Voltage

(ms)

Temp. Range

Package

Pb-Free

MIC809-5SU

IX

3.3V±5%

2.93

30

–40°C to +85°C

SOT23-3

No

MIC809-5SBC3

IX

3.3V±5%

2.93

30

–40°C to +85°C

SC70-3

No

MIC809-5SUY

IX

3.3V±5%

2.93

30

–40°C to +85°C

SOT23-3

Yes

MIC809-5SYC3

IX

3.3V±5%

2.93

30

–40°C to +85°C

SC70-3

Yes

*Other voltages available. Contact Micrel for details. Minimum order may apply.

IttyBitty is a trademark of Micrel, Inc.