MAX811,812 Datasheet by Maxim Integrated

View All Related Products | Download PDF Datasheet
MAX811IMAX812 4-Pin pP Voltage Monitors w {j W W
19-0411; Rev 6; 5/18
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 VCC supply voltage falls below
a preset threshold, keeping it asserted for at least 140ms
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 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
Benefits and Features
Integrated Voltage Monitor Increases System
Robustness with Added Manual Reset
Precision Monitoring of 3V, 3.3V, and 5V
Power-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
*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)
L
4.63
M
4.38
T
3.08
S
2.93
R
2.63
PART* TEMP RANGE PIN-PACKAGE
MAX811_EUS-T -40°C to +85°C 4 SOT143
MAX812_EUS-T -40°C to +85°C 4 SOT143
MAX811
MAX812
VCC
VCC
RESET
(RESET)
RESET
INPUT
GND
VCC
GND
µP
( ) ARE FOR MAX812
PUSHBUTTON
SWITCH
MR
1
2
4
3
VCC
MR(RESET) RESET
GND
MAX811
MAX812
SOT143
TOP VIEW
( ) ARE FOR MAX812
NOTE: SEE PACKAGE INFORMATION FOR MARKING INFORMATION.
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Typical Operating Circuit Pin Configuration
Ordering Information
Click here for production status of specific part numbers.
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 ......................................................20mA
Output Current, RESET or RESET ....................................20mA
Continuous Power Dissipation (TA = +70°C)
SOT143 (derate 4mW/°C above +70°C) .....................320mW
Operating Temperature Range ........................... -40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range ............................ -65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
(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 SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range VCC
TA = 0°C to +70°C 1.0 5.5 V
TA = -40°C to +85°C 1.2
Supply Current ICC
MAX81_L/M, VCC = 5.5V, IOUT = 0 615 µA
MAX81_R/S/T, VCC = 3.6V, IOUT = 0 2.7 10
Reset Threshold VTH
MAX81_L TA = +25°C 4.54 4.63 4.72
V
TA = -40°C to +85°C 4.50 4.75
MAX81_M TA = +25°C 4.30 4.38 4.46
TA = -40°C to +85°C 4.25 4.50
MAX81_T TA = +25°C 3.03 3.08 3.14
TA = -40°C to +85°C 3.00 3.15
MAX81_S TA = +25°C 2.88 2.93 2.98
TA = -40°C to +85°C 2.85 3.00
MAX81_R TA = +25°C 2.58 2.63 2.68
TA = -40°C to +85°C 2.55 2.70
Reset Threshold Tempco 30 ppm/°C
VCC to Reset Delay (Note 2) VOD = 125mV, MAX81_L/M 40 µs
VOD = 125mV, MAX81_R/S/T 20
Reset Active Timeout Period tRP VCC = VTH(MAX) 140 560 ms
MR Minimum Pulse Width tMR 10 µs
MR Glitch Immunity (Note 3) 100 ns
MR to Reset Propagation
Delay (Note 2) tMD 0.5 µs
MR Input Threshold
VIH VCC > VTH(MAX), MAX81_L/M 2.3
V
VIL 0.8
VIH VCC > VTH(MAX), MAX81_R/S/T 0.7 x VCC
VIL 0.25 x VCC
MR Pull-Up Resistance 10 20 30 kΩ
RESET Output Voltage
(MAX812)
VOH ISOURCE = 150µA, 1.8V < VCC < VTH(MIN) 0.8 x VCC
V
VOL
MAX812R/S/T only, ISINK = 1.2mA,
VCC = VTH(MAX) 0.3
MAX812L/M only, ISINK = 3.2mA,
VCC = VTH(MAX) 0.4
www.maximintegrated.com Maxim Integrated
2
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Absolute Maximum Ratings
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)
Note 1:
Production testing done at TA = +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.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
RESET Output Voltage
(MAX811)
VOL
MAX811R/S/T only, ISINK = 1.2mA,
VCC = VTH(MIN) 0.3
V
MAX811L/M only, ISINK = 3.2mA,
VCC = VTH(MIN) 0.4
ISINK = 50µA, VCC > 1.0V 0.3
VOH
MAX811R/S/T only, ISOURCE = 500µA,
VCC > VTH(MAX) 0.8 x VCC
MAX811L/M only, ISOURCE = 800µA,
VCC > VTH(MAX) VCC - 1.5
www.maximintegrated.com Maxim Integrated
3
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Electrical Characteristics (continued)
vccis 5v \‘\ Vm:Vm : zomv 25mV v‘ou : MW BLUM tzsmv
(TA = +25°C, unless otherwise noted.)
0
SUPPLY CURRENT vs. TEMPERATURE
(MAX81_L/M)
8
MAX811/12-TOC2
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
4
2
6
-40 85
10-15 6035
VCC = 5.5V
VCC = 3V
VCC = 1V
190
POWER-UP RESET TIMEOUT
vs. TEMPERATURE
230
MAX811/12-TOC5
TEMPERATURE (°C)
POWER-UP RESET TIMEOUT (ms)
210
200
220
-40 85
35-15 10 60
MAX81_R/S/T
MAX81_L/M
0
POWER-DOWN RESET DELAY vs. TEMPERATURE
(MAX81_R/S/T)
80
100
MAX811/12-TOC3
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (µs)
40
20
60
-40 85
10-15 6035
VOD = VTH - VCC
VOD = 20mV
VOD = 200mV
VOD = 125mV
RESET THRESHOLD DEVIATION
vs. TEMPERATURE
0.9995
1.0000
1.0005
MAX811/12-TOC6
TEMPERATURE (°C)
NORMALIZED THRESHOLD (V)
0.9985
0.9980
0.9990
-40 8535-15 10 60
0
-40 85
SUPPLY CURRENT vs. TEMPERATURE
(MAX81_R/S/T)
2.0
2.5
3.0
MAX811/12-TOC1
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
10
1.0
0.5
-15 60
1.5
35
VCC = 3.6V
VCC = 3.3V
VCC = 1V
0
POWER-DOWN RESET DELAY vs. TEMPERATURE
(MAX81_L/M)
200
MAX811/12-TOC4
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (µs)
100
50
150
-40 8510-15 6035
VOD = VTH - VCC
VOD = 125mV
VOD = 200mV
VOD = 20mV
Maxim Integrated
4
www.maximintegrated.com
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Typical Operating Characteristics
Detailed Description
Reset Output
A microprocessor’s (μP’s) reset input starts the μP in a
known state. These μP supervisory circuits assert reset
to prevent code execution errors during power-up, power-
down, or brownout conditions.
RESET is guaranteed to be a logic low for VCC > 1V.
Once VCC exceeds the reset threshold, an internal timer
keeps RESET low for the reset timeout period; after this
interval, RESET goes high.
If a brownout condition occurs (VCC dips below the reset
threshold), RESET goes low. Any time VCC goes below
the reset threshold, the internal timer resets to zero, and
RESET goes low. The internal timer starts after VCC
returns above the reset threshold, and RESET remains
low for the reset timeout period.
The manual reset input (MR) can also initiate a reset. See
the Manual Reset Input section.
The MAX812 has an active-high RESET output that is the
inverse of the MAX811’s RESET output.
Manual Reset Input
Many μP-based products require manual reset capabil-
ity, allowing the operator, a test technician, or external
logic circuitry to initiate a reset. A logic low on MR asserts
reset. Reset remains asserted while MR is low, and for
the Reset Active Timeout Period (tRP) after MR returns
high. This input has an internal 20kΩ pull-up resistor, so
it can be left open if it is not used. MR can be driven with
TTL or CMOS-logic levels, or with open-drain/collector
outputs. Connect a normally open momentary switch from
MR to GND to create a manual-reset function; external
debounce circuitry is not required. If MR is driven from
long cables or if the device is used in a noisy environment,
connecting a 0.1μF capacitor from MR to ground provides
additional noise immunity.
Reset Threshold Accuracy
The MAX811/MAX812 are ideal for systems using a 5V
±5% or 3V ±5% power supply with ICs specified for 5V
±10% or 3V ±10%, respectively. They are designed to
meet worst-case specifications over temperature. The
reset is guaranteed to assert after the power supply
falls out of regulation, but before power drops below the
minimum specified operating voltage range for the system
ICs. The thresholds are pre-trimmed and exhibit tight dis-
tribution, reducing the range over which an undesirable
reset may occur.
PIN NAME FUNCTION
MAX811 MAX812
1 1 GND Ground
2 RESET Active-Low Reset Output. RESET remains low while VCC is below the reset threshold or while
MR is held low. RESET remains low for the Reset Active Timeout Period (tRP) after the reset
conditions are terminated.
2 RESET Active-High Reset Output. RESET remains high while VCC is below the reset threshold or while
MR is held low. RESET remains high for Reset Active Timeout Period (tRP) after the reset
conditions are terminated.
3 3 MR
Manual Reset Input. A logic low on MR asserts reset. Reset remains asserted as long as MR
is low and for 180ms after MR returns high. This active-low input has an internal 20kΩ pull-up
resistor. It can be driven from a TTL or CMOS-logic line, or shorted to ground with a switch.
Leave open if unused.
4 4 VCC +5V, +3.3V, or +3V Supply Voltage
www.maximintegrated.com Maxim Integrated
5
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Pin Description
Applications Information
Negative-Going VCC Transients
In addition to issuing a reset to the μP during power-up,
power-down, and brownout conditions, the MAX811/
MAX812 are relatively immune to short duration negative-
going VCC transients (glitches).
Figure 1 shows typical transient durations vs. reset com-
parator overdrive, for which the MAX811/MAX812 do
not generate a reset pulse. This graph was generated
using a negative-going pulse applied to VCC, starting
above the actual reset threshold and ending below it by
the magnitude indicated (reset comparator overdrive).
The graph indicates the typical maximum pulse width a
negative-going VCC transient may have without causing
a reset pulse to be issued. As the magnitude of the tran-
sient increases (goes farther below the reset threshold),
the maximum allowable pulse width decreases. Typically,
a VCC transient that goes 125mV below the reset thresh-
old and lasts 40μs or less (MAX81_L/M) or 20μs or less
(MAX81_T/S/R) will not cause a reset pulse to be issued.
A 0.1μF capacitor mounted as close as possible to VCC
provides additional transient immunity.
Ensuring a Valid RESET Output
Down to VCC = 0V
When VCC falls below 1V, the MAX811 RESET output
no longer sinks current—it becomes an open circuit.
Therefore, high-impedance CMOS-logic inputs connected
to the RESET output can drift to undetermined voltages.
This presents no problem in most applications, since most
μP and other circuitry is inoperative with VCC below 1V.
However, in applications where the RESET output must
be valid down to 0V, adding a pulldown resistor to the
RESET pin will cause any stray leakage currents to flow
to ground, holding RESET low (Figure 2). R1’s value is
not critical; 100kΩ is large enough not to load RESET and
small enough to pull RESET to ground.
A 100kΩ pull-up resistor to VCC is also recommended
for the MAX812 if RESET is required to remain valid for
VCC < 1V.
Figure 1. Maximum Transient Duration without Causing a Reset
Pulse vs. Comparator Overdrive
Figure 2. RESET Valid to VCC = Ground Circuit
5
6
7
8
4
0
1 100 1000
2
1
3
RESET COMPARATOR OVERDRIVE, VTH - VCC (mV)
MAXIMUM TRANSIENT DURATION (ms)
10
TA = +25°C
MAX81 _L/M
MAX81 _R/S/T
R1
VCC
GND
MAX811
RESET
www.maximintegrated.com Maxim Integrated
6
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Interfacing to μPs with
Bidirectional Reset Pins
μPs with bidirectional reset pins (such as the Motorola
68HC11 series) can contend with the MAX811/MAX812
reset outputs. If, for example, the MAX811 RESET output
is asserted high and the μP wants to pull it low, indeter-
minate logic levels may result. To correct such cases,
connect a 4.7kΩ resistor between the MAX811 RESET (or
MAX812 RESET) output and the μP reset I/O (Figure 3).
Buffer the reset output to other system components.
Figure 3. Interfacing to μPs with Bidirectional Reset I/O
4.7k
VCC
GND
RESET
MAX811
RESET
VCC
GND
µP
BUFFER
BUFFERED RESET
TO OTHER SYSTEM
COMPONENTS
www.maximintegrated.com Maxim Integrated
7
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Chip Information
TRANSISTOR COUNT: 341
PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
4 SOT143 U4+1 21-0052 90-0183
www.maximintegrated.com Maxim Integrated
8
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
5 6/15 Updated Benefits and Features and Package Information sections 1, 8
65/18 Updated Absolute Maximum Ratings 2
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. © 2018 Maxim Integrated Products, Inc.
9
MAX811/MAX812 4-Pin μP Voltage Monitors
with Manual Reset Input
Revision History
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.

Products related to this Datasheet

IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4
IC SUPERVISOR 1 CHANNEL SOT143-4