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MAX811/MAX812
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 compo-nents 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 Va preset threshold, keeping it asserted for at least 140ms CC supply voltage falls below after VCC has 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 VCC down to 1V), while the MAX812 has an active-high RESET output. The reset comparator is designed to ignore fast transients on VReset thresholds are available for operation with a variety CC. 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
Typical Operating CircuitVCCVCCVCCMAX811MAX812μPRESET(RESET)RESETINPUTMRGNDGNDPUSHBUTTONSWITCH( ) ARE FOR MAX81219-0411; Rev 6; 5/18
4-Pin μP Voltage Monitorswith Manual Reset Input
Benefits and Features
●Integrated Voltage Monitor Increases System
Robustness with Added Manual Reset?Precision Monitoring of 3V, 3.3V, and 5VPower-Supply Voltages
?140ms Min Power-On-Reset Pulse Width?RESET Output (MAX811), RESET Output(MAX812)
?Guaranteed Over Temperature
?Guaranteed RESET Valid to VCC = 1V (MAX811)?Power-Supply Transient Immunity●Saves Board Space
?No External Components?4-Pin SOT143 Package
●Low Power Consumption Simplifies Power-Supply
Requirements
?6μA Supply Current
Ordering Information
PART*TEMP RANGEPIN-PACKAGEMAX811_EUS-T-40°C to +85°C4 SOT143MAX812_EUS-T
-40°C to +85°C
4 SOT143
*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.
Devices are available in both leaded and lead(Pb)-free packaging.Specify lead-free by replacing “-T” with “+T” when ordering.
RESET THRESHOLD
SUFFIX
VOLTAGE (V)
L4.63M4.38T3.08S2.93R2.63
Pin Configuration
TOP VIEW
GND
1
4
VCC
MAX811MAX812
(RESET) RESET
2
3
MR
SOT143
( ) ARE FOR MAX812
NOTE: SEE PACKAGE INFORMATION FOR MARKING INFORMATION.
MAX811/MAX812
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(MAX81_R/S/T)
3.01COT-2V1/CC = 3.6V112.58XAM)Aμ( TVCC = 3.3VN2.0ERRUC1.5 YLPPU1.0S0.5VCC = 1V0
-40
-15
10
35
60
85
TEMPERATURE (°C)
POWER-DOWN RESET DELAY vs. TEMPERATURE
(MAX81_R/S/T)
100V3OD = VTH - VCCCOT-21/)1s18μXA(M YA80VOD = 20mVLED TES60
ER NWO40
D-REWVOD = 125mVOP20
VOD = 200mV0-40
-15
10
35
60
85
TEMPERATURE (°C)
POWER-UP RESET TIMEOUT
vs. TEMPERATURE
2305COT-21/1)1sMAX81_R/S/T8XmAM( TUO220
EMIT TESE210
R PU-REW200
OMAX81_L/MP190
-40
-15
10
35
60
85
TEMPERATURE (°C)
4-Pin μP Voltage Monitorswith Manual Reset Input
SUPPLY CURRENT vs. TEMPERATURE
(MAX81_L/M)
8
2COT-21/118XAM)AVμ6
CC = 5.5V( TNERRUC4
YLPPUS2
VCC = 3VVCC = 1V0
-40
-15
103560
85
TEMPERATURE (°C)
POWER-DOWN RESET DELAY vs. TEMPERATURE
(MAX81_L/M)
200
4VCOD = VTH - VCCOT-21/)1s18μXA(M YA150
VOD = 20mVLED TESER N100
WOD-REW50
VOOD = 125mVP0
VOD = 200mV-40
-15
10
35
60
85
TEMPERATURE (°C)
RESET THRESHOLD DEVIATION
vs. TEMPERATURE
1.00056COT-21/118XA)VM( 1.0000DLOHSER0.9995HT DEZI0.9990
LAMRON0.99850.9980
-40-1510356085
TEMPERATURE (°C)