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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
4-Pin μP Voltage Monitorswith Manual Reset Input
Absolute Maximum Ratings
Terminal Voltage (with respect to GND) VCC .....................................................................-0.3V to 6.0V All Other Inputs .....................................-0.3V to (VCC + 0.3V)Input Current, VCC, MR ......................................................20mAOutput Current, RESET or RESET ....................................20mAContinuous Power Dissipation (TA = +70°C)
SOT143 (derate 4mW/°C above +70°C) .....................320mW
Operating Temperature Range ...........................-40°C to +85°CJunction Temperature ......................................................+150°CStorage Temperature Range ............................-65°C to +160°CLead Temperature (soldering, 10sec) .............................+300°C
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.
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 TA = +25°C.) (Note 1)
PARAMETER
Operating Voltage RangeSupply Current
SYMBOLVCCICC
CONDITIONS
TA = 0°C to +70°CTA = -40°C to +85°C
MAX81_L/M, VCC = 5.5V, IOUT = 0MAX81_R/S/T, VCC = 3.6V, IOUT = 0MAX81_LMAX81_M
Reset Threshold
VTH
MAX81_TMAX81_SMAX81_R
Reset Threshold TempcoVCC to Reset Delay (Note 2)Reset Active Timeout PeriodMR Minimum Pulse WidthMR Glitch Immunity (Note 3)MR to Reset Propagation Delay (Note 2)
tMDVIH
MR Input Threshold
VILVIHVIL
MR Pull-Up Resistance
VOH
RESET Output Voltage (MAX812)
VOL
ISOURCE = 150μA, 1.8V < VCC < VTH(MIN)MAX812R/S/T only, ISINK = 1.2mA, VCC = VTH(MAX)
MAX812L/M only, ISINK = 3.2mA, VCC = VTH(MAX)
VCC > VTH(MAX), MAX81_L/MVCC > VTH(MAX), MAX81_R/S/T
2.3
0.8
0.7 x VCC
0.25 x VCC
100.8 x VCC
0.30.4
V
20
30
k?V
tRPtMR
VOD = 125mV, MAX81_L/MVOD = 125mV, MAX81_R/S/TVCC = VTH(MAX)
14010
1000.5
TA = +25°CTA = -40°C to +85°CTA = +25°CTA = -40°C to +85°CTA = +25°CTA = -40°C to +85°CTA = +25°CTA = -40°C to +85°CTA = +25°CTA = -40°C to +85°C
4.544.504.304.253.033.002.882.852.582.55
304020
560
2.632.933.084.38
MIN1.01.2
62.74.63
15104.724.754.464.503.143.152.983.002.682.70
ppm/°CμsmsμsnsμsV
TYP
MAX5.5
UNITSVμA
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