Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead 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
(V
CC
= 5V for L/M versions, V
CC
= 3.3V for T/S versions, V
CC
= 3V for R version, T
A
= -40°C to +85°C, unless otherwise noted.
Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
Supply Current
SYMBOL
V
CC
I
CC
CONDITIONS
T
A
= 0°C to +70°C
T
A
= -40°C to +85°C
MAX81_L/M, V
CC
= 5.5V, I
OUT
= 0
MAX81_R/S/T, V
CC
= 3.6V, I
OUT
= 0
MAX81_L
MAX81_M
Reset Threshold
V
TH
MAX81_T
MAX81_S
MAX81_R
Reset Threshold Tempco
V
CC
to Reset Delay (Note 2)
Reset Active Timeout Period
MR
Minimum Pulse Width
MR
Glitch Immunity (Note 3)
MR
to Reset Propagation Delay
(Note 2)
t
MD
V
IH
MR
Input Threshold
V
IL
V
IH
V
IL
MR
Pull-Up Resistance
V
OH
RESET Output Voltage
(MAX812)
I
SOURCE
= 150µA, 1.8V < V
CC
< V
TH(MIN)
MAX812R/S/T only, I
SINK
= 1.2mA,
V
CC
= V
TH(MAX)
MAX812L/M only, I
SINK
= 3.2mA,
V
CC
= V
TH(MAX)
V
CC
> V
TH(MAX)
, MAX81_L/M
V
CC
> V
TH(MAX)
, MAX81_R/S/T
2.3
0.8
0.7 x V
CC
0.25 x V
CC
10
0.8 x V
CC
0.3
0.4
V
20
30
kΩ
V
t
RP
t
MR
V
OD
= 125mV, MAX81_L/M
V
OD
= 125mV, MAX81_R/S/T
V
CC
= V
TH(MAX)
140
10
100
0.5
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
4.54
4.50
4.30
4.25
3.03
3.00
2.88
2.85
2.58
2.55
30
40
20
560
2.63
2.93
3.08
4.38
MIN
1.0
1.2
6
2.7
4.63
15
10
4.72
4.75
4.46
4.50
3.14
3.15
2.98
3.00
2.68
2.70
ppm/°C
µs
ms
µs
ns
µs
V
TYP
MAX
5.5
UNITS
V
µA
V
OL
www.maximintegrated.com
Maxim Integrated | 2
MAX811/MAX812
4-Pin μP Voltage Monitors
with Manual Reset Input
Electrical Characteristics (continued)
(V
CC
= 5V for L/M versions, V
CC
= 3.3V for T/S versions, V
CC
= 3V for R version, T
A
= -40°C to +85°C, unless otherwise noted.
PARAMETER
SYMBOL
CONDITIONS
MAX811R/S/T only, I
SINK
= 1.2mA,
V
CC
= V
TH(MIN)
V
OL
RESET
Output Voltage
(MAX811)
V
OH
MAX811L/M only, I
SINK
= 3.2mA,
V
CC
= V
TH(MIN)
I
SINK
= 50µA, V
CC
> 1.0V
MAX811R/S/T only, I
SOURCE
= 500µA,
V
CC
> V
TH(MAX)
MAX811L/M only, I
SOURCE
= 800µA,
V
CC
> V
TH(MAX)
0.8 x V
CC
V
CC
- 1.5
MIN
TYP
MAX
0.3
0.4
0.3
V
UNITS
Note 1:
Production testing done at T
A
= +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.
www.maximintegrated.com
Maxim Integrated | 3
MAX811/MAX812
4-Pin μP Voltage Monitors
with Manual Reset Input
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(MAX81_R/S/T)
MAX811/12-TOC1
SUPPLY CURRENT vs. TEMPERATURE
(MAX81_L/M)
MAX811/12-TOC2
POWER-DOWN RESET DELAY vs. TEMPERATURE
(MAX81_R/S/T)
V
OD
= V
TH
- V
CC
V
OD
= 20mV
MAX811/12-TOC3
3.0
2.5
SUPPLY CURRENT (μA)
2.0
1.5
1.0
0.5
0
-40
-15
10
35
60
V
CC
= 3.6V
V
CC
= 3.3V
8
100
POWER-DOWN RESET DELAY (μs)
SUPPLY CURRENT (μA)
6
V
CC
= 5.5V
80
60
4
40
V
OD
= 125mV
20
V
OD
= 200mV
0
2
V
CC
= 1V
0
85
-40
-15
TEMPERATURE (°C)
V
CC
= 3V
V
CC
= 1V
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
POWER-DOWN RESET DELAY vs. TEMPERATURE
(MAX81_L/M)
MAX811/12-TOC4
POWER-UP RESET TIMEOUT
vs. TEMPERATURE
MAX81_R/S/T
POWER-UP RESET TIMEOUT (ms)
220
MAX811/12-TOC5
RESET THRESHOLD DEVIATION
vs. TEMPERATURE
MAX811/12-TOC6
200
POWER-DOWN RESET DELAY (μs)
V
OD
= V
TH
- V
CC
V
OD
= 20mV
230
1.0005
1.0000
150
NORMALIZED THRESHOLD (V)
0.9995
100
210
0.9990
50
V
OD
= 125mV
V
OD
= 200mV
-40
-15
10
35
60
85
TEMPERATURE (°C)
200
MAX81_L/M
0.9985
0.9980
0
190
-40
-15
10
35
60
85
TEMPERATURE (°C)
-40
-15
10
35
60
85
TEMPERATURE (°C)
www.maximintegrated.com
Maxim Integrated | 4
MAX811/MAX812
4-Pin μP Voltage Monitors
with Manual Reset Input
Pin Description
PIN
NAME
MAX811
1
2
MAX812
1
—
GND
RESET
Ground
Active-Low Reset Output.
RESET
remains low while V
CC
is below the reset threshold or while
MR
is held low.
RESET
remains low for the Reset Active Timeout Period (t
RP
) after the reset
conditions are terminated.
Active-High Reset Output. RESET remains high while V
CC
is below the reset threshold or while
MR
is held low. RESET remains high for Reset Active Timeout Period (t
RP
) after the reset condi-
tions are terminated.
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.
+5V, +3.3V, or +3V Supply Voltage
FUNCTION
—
2
RESET
3
3
MR
4
4
V
CC
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 V
CC
> 1V.
Once V
CC
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 (V
CC
dips below the
reset threshold),
RESET
goes low. Any time V
CC
goes
below the reset threshold, the internal timer resets to
zero, and
RESET
goes low. The internal timer starts
after V
CC
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 (t
RP
) 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 distribution, reducing the range over which an
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