Maxim MAX824LEUK, MAX824MEUK, MAX824REUK, MAX823MEUK, MAX823REUK Datasheet

_______________General Description

The MAX823/MAX824/MAX825* microprocessor (µP)
supervisory circuits combine reset output, watchdog,
and manual-reset input functions in a 5-pin SOT23-5
package. They significantly improve system reliability
and accuracy compared to separate ICs or discrete
components. The MAX823/MAX824/MAX825 are
specifically designed to ignore fast transients on VCC.

Five preprogrammed reset threshold voltages are
available, designated by the following package
suffixes: L = 4.63V, M = 4.38V, T = 3.08V, S = 2.93V,
and R = 2.63V. All three devices have an active-low
reset output, which is guaranteed to be in the correct
state for VCCdown to 1V. The MAX824/MAX825 also
have an active-high reset output. The following

Selector

Guide

explains the functions offered in this series of

parts.

________________________Applications

Battery-Powered Computers and Controllers
Embedded Controllers
Intelligent Instruments
Automotive Systems
Critical µP Monitoring
Portable/Battery-Powered Equipment

____________________________Features

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

Power Supplies

♦ Operating Current: 10µA (MAX823L/M)

3µA (MAX825T/S/R)

♦ Fully Specified Over Temperature
♦ 140ms Min Power-On Reset
♦ Guaranteed RESET Valid to V

CC

= 1V

♦ Power-Supply Transient Immunity
♦ Watchdog Timer with 1.6sec Timeout

(MAX823/MAX824)

♦ Manual-Reset Input (MAX823/MAX825)
♦ No External Components

MAX823/MAX824/MAX825

5-Pin Microprocessor Supervisory Circuits

________________________________________________________________

Maxim Integrated Products

1

1

5

2

3

4

1

5

2

3

4

1

5

2

3

4

GND

WDI

MR

V

CC

RESET

MAX823

SOT23-5

TOP VIEW

GND

WDI

RESET

V

CC

RESET

MAX824

SOT23-5

GND

MR

RESET

V

CC

RESET

MAX825

SOT23-5

__________________________________________________________Pin Configurations

_____________________Selector Guide

19-0487; Rev 1; 6/97

PART

†

MAX823_EUK
MAX824_EUK -40°C to +85°C

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

5 SOT23-5
5 SOT23-5

______________Ordering Information

†

Insert the desired suffix letter (from the table below) into the
blank to complete the part number.

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone] ext. 3468.

MAX825_EUK -40°C to +85°C 5 SOT23-5

MAX823

Active-Low Reset

✔

Active-High Reset —

FUNCTION

Watchdog Input

✔

MAX824

✔
✔
✔

MAX825

✔
✔

—

Manual-Reset Input

✔

—

✔

SUFFIX

RESET

THRESHOLD (V)

L 4.63

M 4.38

T 3.08
S 2.93
R 2.63

Typical Operating Circuit appears at end of data sheet.
Marking Information appears at end of data sheet.

*Patents Pending

MAX823/MAX824/MAX825

5-Pin Microprocessor Supervisory Circuits

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +4.75V to +5.5V for MAX82_L, VCC= +4.5V to +5.5V for MAX82_M, VCC= +3.15V to +3.6V for MAX82_T, VCC= +3V
to +3.6V for MAX82_S, VCC= +2.7V to +3.6V for MAX82_R, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

TA= +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.

VCC........................................................................-0.3V to +6.0V

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

CC

+ 0.3V)

Input Current, All Pins Except RESET and

RESET..............20mA

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

Rate of Rise, V

CC

............................................................100V/µs

Continuous Power Dissipation (T

A

= +70°C)

SOT23-5 (derate 7.1mW/°C above +70°C)...................571mW

Operating Temperature Range

MAX82_EUK .....................................................-40°C to +85°C

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

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

MAX82_M

TA= +25°C
TA= -40°C to +85°C

WDI and MR
unconnected

4.25 4.50

TA= -40°C to +85°C

TA= 0°C to +70°C

4.31 4.38 4.45

MAX82_T/S/R

MAX82_L/M

MAX82_L

TA= +25°C
TA= -40°C to +85°C

MR unconnected

MAX82_S

CONDITIONS

TA= +25°C
TA= -40°C to +85°C 2.85 3.00

2.89 2.93 2.96

MAX82_T

TA= +25°C
TA= -40°C to +85°C 3.00 3.15

3.04 3.08 3.11

MAX82_L/M
MAX82_T/S/R

mV

5

Reset Threshold Hysteresis

10

MAX82_R

TA= +25°C
TA= -40°C to +85°CV2.55 2.70

V

RST

Reset Threshold

2.59 2.63 2.66

MAX823T/S/R,
MAX824T/S/R

5 12

V

1.2

V

CC

1.0 5.5

MAX823L/M,
MAX824L/M

MAX825L/M

Operating Voltage Range

ms

140 200 280

t

RP

Reset Timeout Period

140 200 280

ppm/°C40

Reset Threshold Temperature
Coefficient

4.50 4.75

10 24

4.5 12

µA

3 8

I

SUPPLY

Supply Current

4.56 4.63 4.70

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX825T/S/R

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +4.75V to +5.5V for MAX82_L, VCC= +4.5V to +5.5V for MAX82_M, VCC= +3.15V to +3.6V for MAX82_T, VCC= +3V
to +3.6V for MAX82_S, V

CC

= +2.7V to +3.6V for MAX82_R, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at

T

A

= +25°C.) (Note 1)

Note 1: Over-temperature limits are guaranteed by design and not production tested.
Note 2: The RESET short-circuit current is the maximum pull-up current when RESET is driven low by a µP bidirectional reset pin.
Note 3: WDI is internally serviced within the watchdog period if WDI is left unconnected.
Note 4: The WDI input current is specified as the average input current when the WDI input is driven high or low. The WDI input is

designed to drive a three-stated-output device with a 10µA maximum leakage current and a maximum capacitive load of
200pF. This output device must be able to source and sink at least 200µA when active.

MAX823/MAX824/MAX825

5-Pin Microprocessor Supervisory Circuits

_______________________________________________________________________________________ 3

V

RST

- VCC= 100mV

MAX824T/S/R, MAX825T/S/R,
VCC= V

RST

max, I

SINK

= 1.2mA

MAX82_L/M, VCC= V

RST

max,

I

SOURCE

= 120µA

MAX824L/M, MAX825L/M,
VCC= V

RST

max, I

SINK

= 3.2mA

VCC> 1.8V, I

SOURCE

= 150µA

MAX82_L/M, RESET = 0V, VCC= 5.5V

CONDITIONS

µs20

VCCto RESET Delay

V

0.3

V

OL

RESET Output Voltage

VCC- 1.5

0.4

0.8V

CC

V

OH

800

UNITSMIN TYP MAXSYMBOLPARAMETER

MAX82_T/S/R, VCC= V

RST

max,

I

SOURCE

= 30µA

0.8V

CC

V

OH

MAX82_T/S/R, VCC= V

RST

min,

I

SINK

= 1.2mA

MAX82_L/M, VCC= V

RST

min,

I

SINK

= 3.2mA

0.3

0.4

TA= -40°C to +85°C, VCC= 1.2V,
VCCfalling, V

BATT

= 0V, I

SINK

= 100µA

TA= 0°C to +70°C, VCC= 1V,
VCCfalling, I

SINK

= 50µA

V

0.3

V

OL

RESET Output Voltage

0.3

MAX82_T/S/R, RESET = 0V, VCC= 3.6V

µA

400

I

SOURCE

RESET Output Short-Circuit
Current (Note 2)

VIL= 0.4V, VIH= 0.8V

CC

ns50t

WDI

WDI Pulse Width

sec1.12 1.60 2.40t

WD

Watchdog Timeout Period

WDI = 0V, time average

WDI = VCC, time average

VCC= 5V

µA

-20 -15

WDI Input Current (Note 4)

120 160

V

0.7V

CC

V

IH

WDI Input Threshold (Note 3)

0.3V

CC

V

IL

µs1.0

MR Pulse Width

V

0.7V

CC

V

IH

MR Input Threshold

0.3V

CC

V

IL

kΩ35 52 75

MR Pull-Up Resistance (internal)

ns500

MR to Reset Delay

ns100

MR Noise Immunity (pulse width
with no reset)

MANUAL-RESET INPUT (MAX823/MAX825)

WATCHDOG INPUT (MAX823/MAX824)