General Description

The MAX706P/R/S/T, MAX706AP/AR/AS/AT, and

MAX708R/S/T microprocessor (µP) supervisory circuits

reduce the complexity and number of components

required to monitor +3V power-supply levels in +3V to

+5V µP systems. These devices significantly improve

system reliability and accuracy compared to separate

ICs or discrete components.

The MAX706P/R/S/T and MAX706AP/AR/AS/AT supervi-

sory circuits provide the following four functions:

1) A reset output during power-up, power-down, and

brownout conditions.

2) An independent watchdog output that goes low if the

watchdog input has not been toggled within 1.6s.

3) A 1.25V threshold detector for power-fail warning,

low-battery detection, or for monitoring a power

supply other than the main supply.

4) An active-low, manual-reset input.

The only difference between the MAX706R/AR,

MAX706S/AS, and MAX706T/AT is the reset-threshold

voltage levels, which are 2.63V, 2.93V, and 3.08V,

respectively. All have active-low reset output signals.

The MAX706P/AP are identical to the MAX706R/AR,

except the reset output signal is active-high. The watch-

dog timer function for the MAX706AP/AR/AS/AT dis-

ables when the WDI input is left open or connected to a

high-impedance state of a low-leakage tri-state output.

The MAX708R/S/T provide the same functions as the

MAX706R/S/T and MAX706AR/AS/AT except they do

not have a watchdog timer. Instead, they provide both

RESET and RESET outputs. As with the MAX706,

devices with R, S, and T suffixes have reset thresholds

of 2.63V, 2.93V, and 3.08V, respectively.

These devices are available in 8-pin SO, DIP, and

ating temperature range.

Applications

Battery-Powered Equipment

Portable Instruments

Computers

Controllers

Intelligent Instruments

Critical µP Power Monitoring

Features

♦ µMAX Package, Small 8-Pin SO

♦ Precision Supply-Voltage Monitors

2.63V (MAX706P/R, MAX706AP/AR, and MAX708R)

2.93V (MAX706S, MAX706AS, and MAX708S)

3.08V (MAX706T, MAX706AT, and MAX708T)

♦ 200ms Reset Time Delay

♦ Debounced TTL/CMOS-Compatible Manual Reset

Input

♦ 100µA Quiescent Current

♦ WDI Disable Feature (MAX706AP/AR/AS/AT)

♦ Watchdog Timer: 1.6s Timeout

♦ Reset Output Signal:

Active-High Only (MAX706P, MAX706AP)

Active-Low Only (MAX706R/S/T, MAX706AR/AS/AT)

Active-High and Active-Low (MAX708R/S/T)

♦ Voltage Monitor for Power-Fail or Low-Battery

Warning

♦ 8-Pin Surface-Mount Package

+3V Voltage Monitoring, Low-Cost µP

Supervisory Circuits

________________________________________________________________ Maxim Integrated Products

1

Ordering Information

19-0099; Rev 5; 4/06

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information continued at end of data sheet.

Pin Configurations appear at end of data sheet.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

PART†

TEMP

RANGE

PIN-

PACKAGE

PKG

CODE

MAX706PCPA

0°C to +70°C

8 PDIP

P8-1

MAX706PCSA

0°C to +70°C

8 SO

S8-2

MAX706PCUA

0°C to +70°C

8 µMAX

U8-1

MAX706PEPA

-40°C to +85°C

8 PDIP

P8-1

PFI

GND

MR

PFO

WDO

RESET

UNREGULATED

DC

PUSHBUTTON

SWITCH

WDI

I/O LINE

INTERRUPT

µP

MAX639

DC-DC

CONVERTER

+3V/+3.3V

MAX706R/S/T

MAX706AR/AS/AT

RESET

NMI

Typical Operating Circuits

Typical Operating Circuits continued at end of data sheet.