MAX823/4/5

Voltage Supervisor with Watchdog Timer

and Manual Reset

Revision 1.0

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

January 14, 2014

Revision 1.0

General Description

The MAX823/4/5 voltage supervisory circuits combine

low-current, manual reset input, watchdog timer, active-

high and active-low push-pull outputs. The reset outputs

are asserted and held when the supply voltage falls below

the factory-programmed threshold voltage, when the /MR

pin is pulled low, or if the watchdog times out. Reset is

asserted for the reset timeout delay after the supply

voltage increases above the rising threshold voltage or

when manual reset input is asserted high.

The MAX823/4/5 features an integrated pull-up resistor on

the /MR pin. An active-low push-pull reset output (/RESET)

and an active-high reset output (RESET) provide flexibility

when interfacing with various microcontrollers, PMICs, or

load

switches.

The

watchdog

input

can

be

left

unconnected for applications that do not require watchdog

monitoring.

The MAX823/4/5 consumes a quiescent current of only

3.8µA and is offered in standard SOT23-5 and SC70-5

packages. It is rated for the

–40°C to +125°C temperature

range.

Datasheets and support documentation are available on

Micrel’s web site at: www.micrel.com.

Features

 Precision 1.665V to 4.625V power supply monitor

 ±0.5% threshold accuracy at TA = +25°C

 ±1.5% threshold accuracy from TA = –40°C to +125°C

 3.8µA supply current (S,R,T,W,Y,Z options)

 4.8µA supply current (L,M options)

 Manual reset input (MAX823/5)

 140ms (min.) reset timeout period

 1.6s (typ.) watchdog timeout period

 Active-high and active-low push-pull outputs

 Guaranteed reset output valid to VCC = 1V

 40°C to +125°C junction temperature range

 5-pin SOT23 & SC70 packages

 8x lower watchdog input current than competition

Applications

 Computers and Controllers

 Embedded Controllers

 Intelligent Instruments

 Automotive Systems

 Critical µP Monitoring

 Portable/ Battery-Powered Equipment

Typical Application