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General Description

The MAX6361–MAX6364 supervisory circuits reduce the

complexity and number of components required for

power-supply monitoring and battery control functions in

microprocessor (µP) systems. The circuits significantly

improve system reliability and accuracy compared to that

obtainable with separate ICs or discrete components.

Their functions include µP reset, backup battery

switchover, and power failure warning.

The MAX6361–MAX6364 operate from supply voltages as

low as +1.2V. The factory-preset reset threshold voltage

ranges from 2.32V to 4.63V (see

Ordering Information

These devices provide a manual reset input (MAX6361),

watchdog timer input (MAX6362), battery-on output

(MAX6363), and an auxiliary adjustable reset input

(MAX6364). In addition, each part type is offered in three

reset output versions: an active-low open-drain reset, an

active-low open-drain reset, and an active-high open-

drain reset (see

Selector Guide

at end of data sheet).

Applications

Features

o Low +1.2V Operating Supply Voltage

or V

BATT

)

o Precision Monitoring of +5.0V, +3.3V, +3.0V, and

+2.5V Power-Supply Voltages

o Debounced Manual Reset Input (MAX6361)

o Watchdog Timer with 1.6s Timeout Period

(MAX6362)

o Battery-On Output Indicator (MAX6363)

o Auxiliary User-Adjustable RESET IN (MAX6364)

o Three Available Output Structures

Push-Pull RESET, Open-Drain RESET,

Open-Drain RESET

o RESET/RESET Valid Down to 1.2V Guaranteed

or V

BATT

)

o Power-Supply Transient Immunity

o 150ms (min) Reset Timeout Period

o Small 6-Pin SOT23 Package

MAX6361–MAX6364

SOT23, Low-Power µP Supervisory Circuits

with Battery Backup

________________________________________________________________

Maxim Integrated Products

19-1615; Rev 4; 10/11

Ordering Information

Pin Configurations

Note: These parts offer a choice of reset threshold voltages.

From the table below, select the suffix corresponding to the

desired threshold voltage and insert it into the part number to

complete it. When ordering from the factory, there is a 2500-

piece minimum on the SOT package (tape-and-reel only).

Devices are available in both leaded and lead-free packaging.

Specify lead-free by replacing "-T" with "+T" when ordering.

GND

16BATT

5 OUT

RESET, RESET

MAX6361

TOP VIEW

SOT23-6

Computers

Controllers

Intelligent Instruments

Critical µP/µC

Power Monitoring

Fax Machines

Industrial Control

POS Equipment

Portable/Battery-Powered

Equipment

Selector Guide appears at end of data sheet.

Typical Operating Circuit appears at end of data sheet.

Pin Configurations continued at end of data sheet.

6 SOT23-40°C to +85°CMAX6364HUT_ _-T

6 SOT23-40°C to +85°CMAX6364PUT_ _-T

6 SOT23-40°C to +85°C

MAX6364LUT_ _-T

6 SOT23-40°C to +85°C

6 SOT23-40°C to +85°CMAX6363HUT_ _-T

MAX6363PUT_ _-T

6 SOT23-40°C to +85°C

MAX6363LUT_ _-T

6 SOT23

PIN-PACKAGETEMP RANGE

-40°C to +85°C

MAX6361HUT_ _-T

6 SOT23-40°C to +85°CMAX6361PUT_ _-T

MAX6361LUT_ _-T

PART

6 SOT23-40°C to +85°CMAX6362HUT_ _-T

6 SOT23-40°C to +85°CMAX6362PUT_ _-T

6 SOT23-40°C to +85°C

MAX6362LUT_ _-T

SUFFIX

MIN

46 4.50 4.63

MAXTYP

44 4.25 4.38

31 3.00 3.08

4.75

4.50

3.15

23 2.25

29 2.85 2.93

2.32

26 2.55 2.63

2.38

3.00

2.70

RESET THRESHOLD RANGES (V)

Summary of content (11 pages)

PAGE 1
9-1615; Rev 4; 10/11 SOT23, Low-Power µP Supervisory Circuits with Battery Backup The MAX6361–MAX6364 supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery control functions in microprocessor (µP) systems. The circuits significantly improve system reliability and accuracy compared to that obtainable with separate ICs or discrete components. Their functions include µP reset, backup battery switchover, and power failure warning.
PAGE 2
MAX6361–MAX6364 SOT23, Low-Power µP Supervisory Circuits with Battery Backup ABSOLUTE MAXIMUM RATINGS Terminal Voltages (with respect to GND) VCC, BATT, OUT.......................................................-0.3V to +6V RESET (open drain), RESET (open drain) ................-0.3V to +6V BATT ON, RESET (push-pull), RESET IN, WDI.......................................................-0.3V to (VOUT + 0.3V) MR .............................................................-0.3V to (VCC + 0.
PAGE 3
SOT23, Low-Power µP Supervisory Circuits with Battery Backup (VCC = +2.4V to +5.5V, VBATT = 3V, TA = -40°C to +85°C, reset not asserted. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL VOL RESET Output Voltage CONDITIONS Reset asserted, VBATT = 0V MIN TYP MAX UNITS ISINK = 1.6mA, VCC ≥ 2.1V 0.3 ISINK = 100µA, VCC ≥ 1.2V 0.4 V 0.
PAGE 4
Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) SUPPLY CURRENT vs. TEMPERATURE (NO LOAD) 16 14 -20 0.6 VBATT = 2.0V 0.4 0.2 20 40 60 6 5 VBATT = 2.0V 4 VBATT = 2.8V 3 2 VBATT = 5.0V 1 IOUT = 25mA VCC = 0V 0 -40 80 MAX6361 toc03 MAX6361 toc02 0.8 0 0 -20 0 20 40 60 80 -40 -20 0 80 RESET TIMEOUT PERIOD vs. TEMPERATURE VCC TO RESET PROPAGATION DELAY vs. TEMPERATURE MAX6361 toc04 VCC = 3.0V IOUT = 65mA 0.6 VCC = 4.5V IOUT = 150mA 0.
PAGE 5
SOT23, Low-Power µP Supervisory Circuits with Battery Backup 6 5 VBATT = 2.5V 4 1.235 3 2 MAX6361 toc11 2.8 PROPAGATION DELAY (µs) VBATT = 2.8V 7 THRESHOLD (V) BATTERY SUPPLY CURRENT (µA) MAX6361 toc10 VTH = 2.93V 8 1.236 MAX6361 toc09 10 9 MAX6364 RESET IN TO RESET PROPAGATION DELAY vs. TEMPERATURE MAX6364 RESET IN THRESHOLD vs. TEMPERATURE BATTERY SUPPLY CURRENT vs. SUPPLY VOLTAGE VOD = 50mV 2.5 2.2 1.9 1.6 1.3 1 VBATT = 2.3V 0 0 1.234 1 2 3 VCC (V) 4 1.
PAGE 6
MAX6361–MAX6364 SOT23, Low-Power µP Supervisory Circuits with Battery Backup Detailed Description The Typical Operating Circuit shows a typical connection for the MAX6361–MAX6364 family. OUT powers the static random-access memory (SRAM). OUT is internally connected to VCC if VCC is greater than the reset threshold, or to the greater of VCC or VBATT when VCC is less than the reset threshold. OUT can supply up to 150mA from VCC. When VCC is higher than VBATT, the BATT ON (MAX6363) output is low.
PAGE 7
SOT23, Low-Power µP Supervisory Circuits with Battery Backup Replacing the Backup Battery If BATT is decoupled with a 0.1µF capacitor to ground, the backup power source can be removed while VCC remains valid without danger of triggering a reset pulse. The device does not enter battery-backup mode when VCC stays above the reset threshold voltage. Reset Output A µP’s reset input starts the µP in a known state.
PAGE 8
MAX6361–MAX6364 SOT23, Low-Power µP Supervisory Circuits with Battery Backup Watchdog Software Considerations (MAX6362 Only) To help the watchdog timer monitor software execution more closely, set and reset the watchdog input at different points in the program, rather than “pulsing” the watchdog input low-high-low. This technique avoids a “stuck” loop, in which the watchdog timer would continue to be reset within the loop, keeping the watchdog from timing out.
PAGE 9
SOT23, Low-Power µP Supervisory Circuits with Battery Backup PART MANUAL RESET INPUT MR MAX6361LUT_ _ MAX6361PUT_ _ MAX6361HUT_ _ WATCHDOG INPUT WDI BATT ON RESET IN RESET PUSHPULL RESET OPEN DRAIN RESET OPEN DRAIN MAX6362LUT_ _ MAX6362PUT_ _ MAX6362HUT_ _ MAX6363LUT_ _ MAX6363PUT_ _ MAX6363HUT_ _ MAX6364LUT_ _ MAX6364PUT_ _ MAX6364HUT_ _ Device Marking Codes PART TOP MARK PART TOP MARK PART TOP MARK PART TOP MARK M
PAGE 10
MAX6361–MAX6364 SOT23, Low-Power µP Supervisory Circuits with Battery Backup Pin Configurations (continued) TOP VIEW RESET, RESET 1 GND 2 MAX6362 WDI 3 RESET, RESET 1 6 BATT 5 OUT GND 2 4 VCC BATT ON 3 SOT23-6 MAX6363 RESET, RESET 1 6 BATT 5 OUT GND 2 4 VCC RESET IN 3 MAX6364 6 BATT 5 OUT 4 VCC SOT23-6 SOT23-6 Typical Operating Circuit Chip Information PROCESS: BiCMOS UNREGULATED DC VOLTAGE 2.4V TO 5.5V VCC R1 0.
PAGE 11
SOT23, Low-Power µP Supervisory Circuits with Battery Backup REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 1/00 Initial release — 3 11/05 Added lead-free information. 1 4 10/11 Updated Electrical Characteristics. 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.