19-0411; Rev 4; 12/05
4-Pin µP Voltage Monitors
with Manual Reset Input
________________General Description
____________________________Features
The MAX811/MAX812 are low-power microprocessor
(µP) supervisory circuits used to monitor power sup-
plies in µP and digital systems. They provide excellent
circuit reliability and low cost by eliminating external
components and adjustments when used with 5V-
powered or 3V-powered circuits. The MAX811/MAX812
also provide a debounced manual reset input.
♦ Precision Monitoring of 3V, 3.3V, and 5V
Power-Supply Voltages
♦ 6µA Supply Current
♦ 140ms Min Power-On Reset Pulse Width;
Output (MAX811), RESET Output (MAX812)
♦ Guaranteed Over Temperature
These devices perform a single function: They assert a
reset signal whenever the V
supply voltage falls
CC
♦ Guaranteed
Valid to V
= 1V (MAX811)
CC
below a preset threshold, keeping it asserted for at
least 140ms after V has risen above the reset thresh-
♦ Power-Supply Transient Immunity
♦ No External Components
CC
old. The only difference between the two devices is that
the MAX811 has an active-low RESET output (which is
♦ 4-Pin SOT143 Package
guaranteed to be in the correct state for V
down to
CC
1V), while the MAX812 has an active-high RESET out-
put. The reset comparator is designed to ignore fast
_______________Ordering Information
PART*
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
transients on V . Reset thresholds are available for
CC
operation with a variety of supply voltages.
MAX811_EUS-T
MAX812_EUS-T
4 SOT143
4 SOT143
Low supply current makes the MAX811/MAX812 ideal
for use in portable equipment. The devices come in a
4-pin SOT143 package.
*This part offers a choice of five different reset threshold volt-
ages. Select the letter corresponding to the desired nominal
reset threshold voltage, and insert it into the blank to complete
the part number.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
________________________Applications
Computers
Controllers
RESET THRESHOLD
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
SUFFIX
VOLTAGE (V)
4.63
L
M
T
4.38
3.08
S
2.93
R
2.63
___________________Pin Configuration
___________Typical Operating Circuit
TOP VIEW
V
CC
1
4
GND
V
CC
V
V
CC
CC
MAX811
MAX812
P
MAX811
MAX812
RESET
INPUT
RESET
(RESET)
MR
(RESET) RESET
2
3
MR
GND
GND
SOT143
( ) ARE FOR MAX812
PUSHBUTTON
SWITCH
( ) ARE FOR MAX812
NOTE: SEE LAST PAGE FOR MARKING INFORMATION.
________________________________________________________________ Maxim Integrated Products
1
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.