July 2005

1

MIC1815

MIC1815

Micrel

MIC1815

Microprocessor Reset Circuit

General Description

The MIC1815 is an inexpensive microprocessor supervisory

circuit that monitors power supplies in microprocessor based

systems.

The function of these devices is to assert a reset if the power

supplydropsbelowadesignatedresetthresholdlevel.Several

different reset threshold levels are available to accommodate

10% or 20% drop in 3.3V powered systems.

The MIC1815 has an active low /RESET output. The reset

output is guaranteed to remain asserted for a minimum of

old level. The MIC1815 comes in a 3-pin SOT-23 package.

Typical Application

VCC

RESET

µP

RESET

VCC

MIC1815

VCC

Features

• Precision voltage monitor for 10% or 20% drop in 3.3V

power supplies

• 5µA supply current

• 100ms minimum reset pulse width

• No external components required

• Available in 3-pin SOT-23 package

Applications

• Portable equipment

• Intelligent instruments

• Critical microprocessor power monitoring

• Printers/computers

• Embedded controllers

Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 474-1000 • fax + 1 (408) 944-0970 • http://www.micrel.com

Ordering Information

Threshold

Part Number

Marking

Voltage

Operating Temp. Range

Package

Pb-Free

MIC1815-10U

ND

2.88V

–40°C to +85°C

SOT-23

No

MIC1815-20U

NE

2.55V

–40°C to +85°C

SOT-23

No

MIC1815-10UY

ND

2.88V

–40°C to +85°C

SOT-23

Yes

MIC1815-20UY

NE

2.55V

–40°C to +85°C

SOT-23

Yes