Maxim MAX812TEUS-T, MAX812SEUS-T, MAX812REUS-T, MAX812MEUS-T, MAX811LEUS-T Datasheet

________________General Description

The MAX811/MAX812 are low-power microprocessor
(µP) supervisory circuits used to monitor power sup­plies in µP and digital systems. They provide excellent
circuit reliability and low cost by eliminating external
components and adjustments when used with 5V­powered or 3V-powered circuits. The MAX811/MAX812
also provide a debounced manual reset input.

These devices perform a single function: They assert a
reset signal whenever the VCCsupply voltage falls
below a preset threshold, keeping it asserted for at
least 140ms after VCChas risen above the reset thresh­old. The only difference between the two devices is that
the MAX811 has an active-low RESET output (which is
guaranteed to be in the correct state for V

CC

down to
1V), while the MAX812 has an active-high RESET out­put. The reset comparator is designed to ignore fast
transients on VCC. Reset thresholds are available for
operation with a variety of supply voltages.

Low supply current makes the MAX811/MAX812 ideal
for use in portable equipment. The devices come in a
4-pin SOT143 package.

________________________Applications

Computers

Controllers

Intelligent Instruments

Critical µP and µC Power Monitoring

Portable/Battery-Powered Equipment

____________________________Features

♦ Precision Monitoring of 3V, 3.3V, and 5V

Power-Supply Voltages

♦ 6µA Supply Current

♦ 140ms Min Power-On Reset Pulse Width;

RREESSEETT

Output (MAX811), RESET Output (MAX812)

♦ Guaranteed Over Temperature

♦ Guaranteed

RREESSEETT

Valid to V

CC

= 1V (MAX811)

♦ Power-Supply Transient Immunity

♦ No External Components

♦ 4-Pin SOT143 Package

MAX811/MAX812

4-Pin µP Voltage Monitors

with Manual Reset Input

________________________________________________________________ Maxim Integrated Products 1

1

2

4

3

V

CC

MR(RESET) RESET

GND

MAX811
MAX812

SOT143

TOP VIEW

( ) ARE FOR MAX812

NOTE: SEE LAST PAGE FOR MARKING INFORMATION.

___________________Pin Configuration

MAX811
MAX812

V

CC

V

CC

RESET

(RESET)

RESET
INPUT

GND

V

CC

GND

µP

( ) ARE FOR MAX812

PUSHBUTTON

SWITCH

MR

___________Typical Operating Circuit

19-0411; Rev 3; 3/99

PART*

MAX811_EUS-T

MAX812_EUS-T -40°C to +85°C

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

4 SOT143

4 SOT143

_______________Ordering Information

* This part offers a choice of five different reset threshold

voltages. Select the letter corresponding to the desired
nominal reset threshold voltage, and insert it into the blank
to complete the part number.

RESET THRESHOLD

SUFFIX VOLTAGE (V)

L 4.63

M 4.38

T 3.08

S 2.93

R 2.63

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

MAX811/MAX812

4-Pin µP Voltage Monitors
with Manual Reset Input

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= 5V for L/M versions, VCC= 3.3V for T/S versions, VCC= 3V for R version, TA= -40°C to +85°C, unless otherwise noted.
Typical values are at T

A

= +25°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

Terminal Voltage (with respect to GND)

V

CC

......................................................................-0.3V to 6.0V

All Other Inputs.......................................-0.3V to (V

CC

+ 0.3V)

Input Current, V

CC,

MR .......................................................20mA

Output Current, RESET or RESET .......................................20mA

Continuous Power Dissipation (T

A

= +70°C)

SOT143 (derate 4mW/°C above +70°C) 320mW

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range .............................-65°C to +160°C

Lead Temperature (soldering, 10sec) .............................+300°C

I

SOURCE

= 150µA, 1.8V < VCC< V

TH(MIN)

MAX81_R/S/T, VCC= 3.6V, I

OUT

= 0

MAX81_L/M, VCC= 5.5V, I

OUT

= 0

TA= -40°C to +85°C

VOD= 125mV, MAX81_R/S/T

VOD= 125mV, MAX81_L/M

MAX81_S

MAX81_L

MAX81_M

VCC= V

TH(MAX)

CONDITIONS

0.8V

CC

2.3V

IH

µs0.5t

MD

MR to Reset Propagation Delay
(Note 2)

ns100

MR Glitch Immunity (Note 3)

µs10t

MR

MR Minimum Pulse Width

ms140 560t

RP

Reset Active Timeout Period

µA

2.7 10

I

CC

Supply Current

615

V

1.2

V

CC

Operating Voltage Range

µs

20

VCCto Reset Delay (Note 2)

40

2.88 2.93 2.98

3.03 3.08 3.14

Reset Threshold

4.54 4.63 4.72

4.50 4.75

4.30 4.38 4.46

4.25 4.50

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX812L/M only, I

SINK

= 3.2mA,

VCC= V

TH(MAX)

MAX812R/S/T only, I

SINK

= 1.2mA,

VCC= V

TH(MAX)

V

0.4

V

OL

RESET Output Voltage
(MAX812)

0.3

V

OH

VCC> V

TH(MAX)

, MAX81_L/M

0.8V

IL

VCC> V

TH(MAX)

, MAX81_R/S/T

V

0.25 x V

CC

V

IL

MR Input Threshold

0.7 x V

CC

V

IH

kΩ10 20 30

MR Pull-Up Resistance

TA= 0°C to +70°C 1.0 5.5

3.00 3.15

2.85 3.00

ppm/°C30Reset Threshold Tempco

MAX81_R

2.58 2.63 2.68

2.55 2.70

TA = +25°C

TA = -40°C to +85°C

TA = +25°C

TA = -40°C to +85°C

MAX81_T

TA = +25°C

TA = -40°C to +85°C

TA = +25°C

TA = -40°C to +85°C

TA = +25°C

TA = -40°C to +85°C

V

TH

V

MAX811/MAX812

4-Pin µP Voltage Monitors

with Manual Reset Input

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= 5V for L/M versions, VCC= 3.3V for T/S versions, VCC= 3V for R version, TA= -40°C to +85°C, unless otherwise noted.
Typical values are at T

A

= +25°C.) (Note 1)

Note 1: Production testing done at T

A

= +25°C, over temperature limits guaranteed by design using six sigma design limits.

Note 2: RESET output for MAX811, RESET output for MAX812.
Note 3: “Glitches” of 100ns or less typically will not generate a reset pulse.

MAX811R/S/T only, I

SINK

= 1.2mA,

VCC= V

TH(MIN)

MAX811L/M only, I

SOURCE

= 800µA,

VCC> V

TH(MAX)

MAX811L/M only, I

SINK

= 3.2mA,

VCC= V

TH(MIN)

I

SINK

= 50µA, VCC> 1.0V

MAX811R/S/T only, I

SOURCE

= 500µA,

V

CC

> V

TH(MAX)

CONDITIONS

0.3

V

VCC- 1.5

V

OH

RESET Output Voltage
(MAX811)

0.4

0.3

V

OL

0.8V

CC

UNITSMIN TYP MAXSYMBOLPARAMETER