Datasheet

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_______________General Description

These microprocessor (µP) supervisory circuits reduce

the complexity and number of components required for

power-supply monitoring and battery-control functions

in µP systems. They significantly improve system relia-

bility and accuracy compared to separate ICs or

discrete components.

These devices are designed for use in systems powered

by 3.0V or 3.3V supplies. See the selector guide in the

back of this data sheet for similar devices designed for

5V systems. The suffixes denote different reset threshold

voltages: 3.075V (T), 2.925V (S), and 2.625V (R) (see the

Reset Threshold section in the Detailed Description). All

these parts are available in 8-pin DIP and SO packages.

Functions offered in this series are as follows:

________________________Applications

Battery-Powered Computers and Controllers

Embedded Controllers

Intelligent Instruments

Automotive Systems

Critical µP Power Monitoring

Portable Equipment

____________________________Features

♦

–

—

–

and RESET Outputs

♦ Manual Reset Input

♦ Precision Supply-Voltage Monitor

♦ 200ms Reset Time Delay

♦ Watchdog Timer (1.6s timeout)

♦ Battery-Backup Power Switching—

Battery Can Exceed V

in Normal Operation

♦ 40µA V

Supply Current

♦ 1µA Battery Supply Current

♦ Voltage Monitor for Power-Fail or

Low-Battery Warning

♦ Guaranteed

–

—

–

Assertion to V

= 1V

♦ 8-Pin DIP and SO Packages

______________Ordering Information

MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R

3.0V/3.3V Microprocessor Supervisory Circuits

________________________________________________________________ Maxim Integrated Products 1

MAX690T/S/R

MAX802T/S/R

MAX804T/S/R

MAX805T/S/R

0.1μF

OUT

RESET

(RESET)

PFO

WDI

VBATT

GND

0.1μF

3.6V

LITHIUM

BATTERY

CMOS RAM

μP

RESET

NMI

I/O LINE

UNREGULATED

REGULATED +3.3V OR +3.0V

BUS

( ) ARE FOR MAX804T/S/R, MAX805T/S/R

PFI

See last page for MAX704T/S/R, MAX806T/S/R.

__________________Pin Configuration

DIP/SO

TOP VIEW

PFO

VBATT

RESET (RESET)

WDI

<MR>

OUT

GND

PFI

MAX690T/S/R

MAX704T/S/R

MAX802T/S/R

MAX804T/S/R

MAX805T/S/R

MAX806T/S/R

( )

ARE FOR MAX804T/S/R, MAX805T/S/R

< > ARE FOR MAX704T/S/R, MAX806T/S/R

_________Typical Operating Circuits

19-0243; Rev 2; 12/05

PART** TEMP RANGE

MAX690_CPA

0°C to +70°C

MAX690_CSA 0°C to +70°C

MAX690_C/D 0°C to +70°C Dice*

8 SO

8 Plastic DIP

PIN-PACKAGE

Part

MAX690_EPA -40°C to +85°C

MAX690_ESA -40°C to +85°C

MAX690_MJA -55°C to +125°C 8 CERDIP

8 SO

8 Plastic DIP

Active-Low Reset

Active-High Reset

Watchdog Input

Manual Reset

Input

Backup-Battery

Switch

Power-Fail

Threshold Accuracy

Power-Fail

Comparator

Reset Window

MAX690

✓✓ ✓

±4%

✓

±75mV

MAX704

✓✓✓

±4%

✓

±75mV

MAX802

✓✓ ✓

±2%

✓

±2%

MAX804

✓✓ ✓

±2%

✓

±2%

MAX805

✓✓ ✓

±4%

✓

±75mV

MAX806

✓✓✓

±2%

✓

±2%

Ordering Information continued at end of data sheet.

*Contact factory for dice specifications.

**These parts offer a choice of reset threshold voltage. Select

the letter corresponding to the desired nominal reset threshold

voltage (T = 3.075V, S = 2.925V, R = 2.625V) and insert it into

the blank to complete the part number.

Devices in PDIP and SO packages are available in both leaded

and lead-free packaging. Specify lead free by adding the +

symbol at the end of the part number when ordering. Lead free

not available for CERDIP package.

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.

Summary of content (12 pages)

PAGE 1
9-0243; Rev 2; 12/05 3.0V/3.3V Microprocessor Supervisory Circuits These microprocessor (µP) supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery-control functions in µP systems. They significantly improve system reliability and accuracy compared to separate ICs or discrete components. These devices are designed for use in systems powered by 3.0V or 3.3V supplies.
PAGE 2
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R 3.0V/3.3V Microprocessor Supervisory Circuits ABSOLUTE MAXIMUM RATINGS Terminal Voltage (with respect to GND) VCC.........................................................................-0.3V to 6.0V VBATT ....................................................................-0.3V to 6.0V All Other Inputs ...................-0.3V to the higher of VCC or VBATT Continuous Input Current VCC ............................................................................
PAGE 3
.0V/3.3V Microprocessor Supervisory Circuits (VCC = 3.17V to 5.5V for the MAX690T/MAX704T/MAX80_T, VCC = 3.02V to 5.5V for the MAX690S/MAX704S/MAX80_S, VCC = 2.72V to 5.5V for the MAX690R/MAX704R/MAX80_R; VBATT = 3.6V; TA = TMIN to TMAX; unless otherwise noted. Typical values are at TA = +25˚C.) PARAMETER SYMBOL CONDITIONS IOUT = 250µA, VBATT = 2.3V VOUT in Battery-Backup Mode MIN TYP VBATT - 0.1 VBATT - 0.034 VBATT - VCC, VSW > VCC > 1.
PAGE 4
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R 3.0V/3.3V Microprocessor Supervisory Circuits ELECTRICAL CHARACTERISTICS (continued) (VCC = 3.17V to 5.5V for the MAX690T/MAX704T/MAX80_T, VCC = 3.02V to 5.5V for the MAX690S/MAX704S/MAX80_S, VCC = 2.72V to 5.5V for the MAX690R/MAX704R/MAX80_R; VBATT = 3.6V; TA = TMIN to TMAX; unless otherwise noted. Typical values are at TA = +25˚C.
PAGE 5
3.0V/3.3V Microprocessor Supervisory Circuits VBATT-to-VOUT ON-RESISTANCE vs. TEMPERATURE VCC = 2.5V VCC = 3.3V 3 2 VCC = 5V 1 140 VBATT = 3V 100 VBATT = 3.3V 60 VCC = 5V VCC = 2.5V 20 40 60 80 100 120 140 –60 –40 –20 0 100 VBATT = 3V 1 212 VCC = 5V 208 RESET-COMPARATOR PROPAGATION DELAY vs. TEMPERATURE VBATT = 3.0V 204 200 VBATT = 2V 30 VBATT = 3.
PAGE 6
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R 3.0V/3.3V Microprocessor Supervisory Circuits ______________________________________________________________Pin Description PIN MAX690 MAX704 MAX804 MAX802 MAX806 MAX805 NAME FUNCTION 1 1 1 VOUT Supply Output for CMOS RAM. When VCC is above the reset threshold, VOUT is connected to VCC through a p-channel MOSFET switch. When VCC falls below VSW and VBATT, VBATT connects to VOUT. Connect to VCC if no battery is used.
PAGE 7
3.0V/3.3V Microprocessor Supervisory Circuits 3.0V OR 3.3V BATTERY SWITCHOVER CIRCUITRY VCC VRST VOUT VCC VSW BATTERY SWITCHOVER COMPARATOR 0V 3.0V OR 3.3V VOUT 1.237V RESET COMPARATOR MAX690T/S/R MAX704T/S/R MAX802T/S/R MAX804T/S/R MAX805T/S/R MAX806T/S/R VBATT = 3.6V VSW tWP 3.0V OR 3.3V RESET 1.
PAGE 8
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R 3.0V/3.3V Microprocessor Supervisory Circuits Backup-Battery Switchover In the event of a brownout or power failure, it may be necessary to preserve the contents of RAM. With a backup battery installed at VBATT, the devices automatically switch RAM to backup power when V CC falls. This family of µP supervisors (designed for 3.3V and 3V systems) doesn’t always connect VBATT to VOUT when VBATT is greater than VCC.
PAGE 9
3.0V/3.3V Microprocessor Supervisory Circuits +5V MAX690T/S/R VOUT MAX704T/S/R MAX802T/S/R MAX804T/S/R VBATT MAX805T/S/R RESET MAX806T/S/R (RESET) VCC 1N4148 3.0V OR 3.3V TO STATIC RAM 1N4148 TO μP TO STATIC RAM TO μP 0.47F 0.47F GND GND a MAX690T/S/R VOUT MAX704T/S/R MAX802T/S/R MAX804T/S/R VBATT MAX805T/S/R RESET MAX806T/S/R (RESET) VCC ( ) ARE FOR MAX804T/S/R, MAX805T/S/R ONLY b ( ) ARE FOR MAX804T/S/R, MAX805T/S/R ONLY Figure 3.
PAGE 10
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R 3.0V/3.
PAGE 11
3.0V/3.3V Microprocessor Supervisory Circuits _Typical Operating Circuits (cont.) 3.0V OR 3.3V VOUT VCC VCC VCC MAX690T/S/R MAX704T/S/R RESET MAX802T/S/R MAX806T/S/R μP 4.7kΩ 0.1µF RESET 3.6V 0.1µF MAX704T/S/R MAX806T/S/R RESET MR GND GND RAM VBATT 0.1µF μP PFI GND Figure 6. Interfacing to µPs with Bidirectional Reset I/O DS690-806 fig7 MAXIMUM TRANSIENT DURATION (μs) 100 80 VCC = 3.3V TA = +25°C 60 40 20 0 10 100 1000 RESET COMPARATOR OVERDRIVE (VRST - VCC) (mV) Figure 7.
PAGE 12
MAX690T/S/R, 704T/S/R, 802T/S/R, 804–806T/S/R 3.0V/3.