MAX811, MAX812
4-Pin µP Reset Monitors
The MAX811 and MAX812 are cost–effective system supervisor
circuits designed to monitor VCC in digital systems and provide a reset
signal to the host processor when necessary. A manual reset input is
provided to override the reset monitor, and is suitable for use as a
push–button reset. No external components are required.
The reset output is driven active within 20 µsec (4 µsec for
F version) of VCC falling through the reset voltage threshold. RESET
is maintained active for a minimum of 140 msec after VCC rises above
the reset threshold. The MAX812 has an active–high RESET output
while the MAX811 has an active–low RESET output. The output of
the MAX811 is guaranteed valid down to VCC = 1 V. Both devices are
available in a 4–Pin SOT–143 package.
The MAX811/12 are optimized to reject fast transient glitches on
the VCC line. Low supply current of 7 µA (VCC = 3.3 V) makes these
devices suitable for battery powered applications.
4
3
1
SOT–143
CASE 318A
2
PIN CONNECTIONS
Features
• Precision VCC Monitor for 1.8 V, 2.7 V, 3.0 V, 3.3 V, 5.0 V
•
•
•
•
•
•
•
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Nominal Supplies
Manual Reset Input
140 msec Guaranteed Minimum RESET, RESET Output Duration
RESET Output Guaranteed to VCC = 1.0 V (MAX811)
Low 7 µA Supply Current
VCC Transient Immunity
Small SOT–143–4 Package
No External Components
GND
MAX811 (RESET)
MAX812 (RESET)
1
4 VCC
2
3 MR
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 6 of this data sheet.
Typical Applications
•
•
•
•
Computers
Embedded Systems
Battery Powered Equipment
Critical µP Power Supply Monitoring
DEVICE MARKING INFORMATION
See general marking information in the device marking
section on page 6 of this data sheet.
VCC
VCC
PROCESSOR
VCC
MR
PUSH–
BUTTON
MAX811
RESET
INPUT
(ACTIVE LOW)
GND
GND
RESET
Typical Operating Circuit
Semiconductor Components Industries, LLC, 2002
May, 2002 – Rev. 4
1
Publication Order Number:
MAX811/D
MAX811, MAX812
MAXIMUM RATINGS*
Symbol
Value
Unit
Supply Voltage (VCC to GND)
Rating
–
+6.0
V
RESET, RESET
–
–0.3 to (VCC +0.3)
V
Input Current, VCC
–
20
mA
Output Current, RESET, RESET
–
20
mA
Operating Temperature Range
TA
–40 to +85
°C
Storage Temperature Range
Tstg
–65 to +150
°C
–
+260
°C
Lead Temperature (Soldering, 10 sec)
*This is a stress rating only and functional operation of the device at these or any other conditions above 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 = 5 V for L/M versions, VCC = 3.3 V for T/S versions, VCC = 3 V for R version,
VCC = 2.0 V for F version. TA = –40°C to +85°C unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
Characteristics
VCC Range
Test Conditions
Symbol
Min
Typ
Max
Unit
–
VCC
1.2
–
5.5
V
VCC VTH, for L, M, R, S, T, F
VCC VTH, for L, M, R, S, T
VCC VTH, for F
ICC
–
–
–
7.0
10
6.0
15
15
12
µA
MAX81_L: TA = +25°C
TA = –40°C to +85°C
MAX81_M: TA = +25°C
TA = –40°C to +85°C
MAX81_T: TA = +25°C
TA = –40°C to +85°C
MAX81_S: TA = +25°C
TA = –40°C to +85°C
MAX81_R: TA = +25°C
TA = –40°C to +85°C
MAX81_F: TA = +25°C
TA = –40°C to +85°C
VTH
4.54
4.50
4.30
4.25
3.03
3.00
2.88
2.85
2.58
2.55
1.71
1.70
4.63
–
4.38
–
3.08
–
2.93
–
2.63
–
1.75
–
4.72
4.75
4.46
4.50
3.14
3.15
2.98
3.00
2.68
2.70
1.79
1.80
V
–
–
–
30
–
ppm/°C
VCC = VTH to VTH –125 mV;
L, M, R, S, T, F
–
–
–
20
5.0
–
–
µsec
VCC = VTH(MAX)
tRP
140
280
560
msec
MR Minimum Pulse Width
–
tMR
10
–
–
µsec
MR Glitch Immunity
–
–
–
0.1
–
µsec
MR to Reset Propagation Delay
–
tMD
–
0.5
–
µsec
VCC VTH(MAX),
MAX81_L/M
VIH
VIL
2.3
–
–
–
–
0.8
V
VCC VTH(MAX),
MAX81_R/S/T/F
VIH
VIL
0.7 VCC
–
–
–
–
0.15 VCC
V
–
–
10
20
40
KΩ
ISOURCE = 150 µA;
VCC VTH(MIN)
VOH
0.8 VCC
–
–
V
Supply Current
Reset Threshold
Reset Threshold Tempco
VCC to Reset Delay
Reset Active Timeout Period
MR Input Threshold
–
MR Pull–up Resistance
RESET Output Voltage High
(MAX812)
1. Production testing done at TA = +25°C, over temperature limits guaranteed by design.
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2
MAX811, MAX812
ELECTRICAL CHARACTERISTICS (continued) (VCC = 5 V for L/M versions, VCC = 3.3 V for T/S versions, VCC = 3 V for R version,
VCC = 2.0 V for F version. TA = –40°C to +85°C unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
Characteristics
RESET Output Voltage Low
(MAX812)
RESET Output Voltage Low
(MAX811)
RESET Output Voltage High
(MAX811)
Symbol
Test Conditions
Min
Typ
Max
Unit
VOL
MAX812F only, ISINK = 500 µA,
VCC = VTH(MAX)
–
–
0.2
V
MAX812R/S/T only, ISINK = 1.2 mA,
VCC = VTH(MAX)
MAX812L/M only, ISINK = 3.2 mA,
VCC = VTH(MAX)
–
–
0.3
–
–
0.4
MAX811R/S/T only, ISINK = 1.2 mA,
VCC = VTH(MIN)
MAX811F only, ISINK = 500 µA,
VCC = VTH(MIN)
–
–
0.3
MAX811L/M only, ISINK = 3.2 mA,
VCC = VTH(MIN)
ISINK = 50 µA, VCC 1.0 V
–
–
0.4
–
–
TBD
MAX811L/M only,
ISOURCE = 800 µA,
VCC VTH(MAX)
MAX811R/S/T/F only,
ISOURCE = 500 µA,
VCC VTH(MAX)
VCC –1.5
–
–
0.8 VCC
–
–
VOL
VOH
V
V
1. Production testing done at TA = +25°C, over temperature limits guaranteed by design.
2. RESET output for MAX811, RESET output for MAX812.
PIN DESCRIPTION
Pin
Number
Symbol
Description
1
GND
2
RESET (MAX811)
Ground
RESET output remains low while VCC is below the reset voltage threshold, and for at least
140 msec min. after VCC rises above reset threshold.
2
RESET (MAX812)
RESET output remains high while VCC is below the reset voltage threshold, and for at least
140 msec min. after VCC rises above reset threshold.
3
MR
Manual Reset input generates a reset when MR is below VIL.
4
VCC
Supply voltage
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3
MAX811, MAX812
APPLICATIONS INFORMATION
resistor to VCC is required for the MAX812 to ensure a valid
high RESET for VCC below 1.1 V.
VCC Transient Rejection
The MAX811/12 provides accurate VCC monitoring and
reset timing during power–up, power–down, and
brownout/sag conditions, and rejects negative–going
transients (glitches) on the power supply line. Figure 1
shows the maximum transient duration vs. maximum
negative excursion (overdrive) for glitch rejection. Any
combination of duration and overdrive that lays under the
curve will not generate a reset signal. Combinations above
the curve are detected as a brownout or power–down.
Transient immunity can be improved by adding a capacitor
in close proximity to the VCC pin of the MAX811/12.
VCC
VCC
MAX811
RESET
R1
100 K
GND
VCC
VTH
Figure 2. Ensuring RESET Valid to VCC = 0 V
Overdrive
Processors with Bidirectional I/O Pins
MAXIMUM TRANSIENT DURATION ( sec)
Duration
Some µP’s (such as Motorola’s 68HC11) have
bi–directional reset pins. Depending on the current drive
capability of the processor pin, an indeterminate logic level
may result if there is a logic conflict. This can be avoided by
adding a 4.7 kΩ resistor in series with the output of the
MAX811/12 (Figure 3). If there are other components in the
system which require a reset signal, they should be buffered
so as not to load the reset line. If the other components are
required to follow the reset I/O of the µP, the buffer should
be connected as shown with the solid line.
400
TA = +25°C
320
240
160
MAX811/12
80
0
1
BUFFER
5
100
1000
Reset Comparator Overdrive, [VCCTP–VCC](mV)
Figure 1. Maximum Transient Duration vs.
Overdrive for Glitch Rejection at 25°C
BUFFERED
RESET TO
OTHER
SYSTEM
COMPONENTS
VCC
VCC
VCC
RESET Signal Integrity During Power–Down
MAX811
4.7 K
The MAX811 RESET output is valid to VCC = 1.0 V.
Below this voltage the output becomes an “open circuit’’ and
does not sink current. This means CMOS logic inputs to the
µP will be floating at an undetermined voltage. Most digital
systems are completely shutdown well above this voltage.
However, in situations where RESET must be maintained
valid to VCC = 0 V, a pull–down resistor must be connected
from RESET to ground to discharge stray capacitances and
hold the output low (Figure 2). This resistor value, though
not critical, should be chosen such that it does not
appreciably load RESET under normal operation (100 kΩ
will be suitable for most applications). Similarly, a pull–up
RESET
GND
P
RESET
GND
Figure 3. Interfacing to Bidirectional Reset I/O
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4
MAX811, MAX812
TYPICAL CHARACTERISTICS
8
14
VCC = 5 V
8
VCC = 3 V
6
4
VCC = 1 V
2
0
–40
POWER–DOWN RESET DELAY ( sec )
SUPPLY CURRENT ( A)
10
–20
0
20
40
60
85
4
VCC = 3 V
2
VCC = 1 V
0
–40
–20
40
60
VOD = 20 mV
VOD = 200 mV
10
VOD = 100 mV
–20
0
20
40
60
85
85
50
L/M
VOD = 20 mV
40
VOD = 100 mV
VOD = 200 mV
30
R/S/T
20
VOD = 200 mV
0
–40
VOD = 20 mV
VOD = 100 mV
10
–20
Temperature (°C)
0
20
40
60
85
Temperature (°C)
Figure 6. Power–Down Reset Delay vs.
Temperature (MAX81xF)
Figure 7. Power–Down Reset Delay vs.
Temperature (MAX81xL/M/R/S/T)
1.003
250
NORMALIZED THRESHOLD (V)
POWER–UP RESET TIMEOUT (msec)
20
Figure 5. Supply Current vs. Temperature
(No Load, MAX81xL/M)
30
245
MAX81xL/M
240
MAX81xR/S/T/F
235
230
225
–40
0
Figure 4. Supply Current vs. Temperature
(No Load, MAX81xR/S/T/F)
40
0
–40
VCC = 5 V
Temperature (°C)
50
20
6
Temperature (°C)
POWER–DOWN RESET DELAY ( sec )
SUPPLY CURRENT ( A)
12
1.002
1.001
1.000
0.999
0.998
0.997
0.996
0.995
0.994
–20
0
20
40
60
–40
85
Temperature (°C)
–15
10
35
60
Temperature (°C)
Figure 8. Power–Up Reset Timeout vs.
Temperature
Figure 9. Normalized Reset Threshold vs.
Temperature
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5
65
MAX811, MAX812
MARKING DIAGRAM
1
2
3
4
1 and 2
3
= Part Number Code and
Temperature Range (two–digit code)
= Year and Quarter Code
4
= Lot ID Number
ORDERING INFORMATION
Threshold
Voltage
1 and 2
MAX811LEUS–T*
MAX811MEUS–T*
MAX811TEUS–T
MAX811SEUS–T*
MAX811REUS–T*
MAX811FEUS–T
4.63
4.38
3.08
2.93
2.63
1.75
S1
S2
S3
S4
S5
S7
MAX812LEUS–T*
MAX812MEUS–T*
MAX812TEUS–T
MAX812SEUS–T*
MAX812REUS–T*
MAX812FEUS–T
4.63
4.38
3.08
2.93
2.63
1.75
T1
T2
T3
T4
T5
T7
Device
Marking
*Default: Contact your ON Semiconductor sales representative for other threshold voltage options.
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6
Package
(Qty/Reel)
3000 Units Tape and Reel
MAX811, MAX812
PACKAGE DIMENSIONS
SOT–143
CASE 318A–05
ISSUE R
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
A
L
G
3
4
S
B
1
F
H
2
D
J
C
R
K
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7
DIM
A
B
C
D
F
G
H
J
K
L
R
S
MILLIMETERS
INCHES
MIN
MAX
MIN
MAX
2.80
3.04
0.110
0.120
1.20
1.39 0.047
0.055
0.84
1.14 0.033
0.045
0.39
0.50 0.015
0.020
0.79
0.93 0.031
0.037
1.78
2.03 0.070
0.080
0.013
0.10 0.0005
0.004
0.08
0.15 0.003
0.006
0.46
0.60 0.018
0.024
0.445
0.60 0.0175
0.024
0.72
0.83 0.028
0.033
2.11
2.48 0.083
0.098
MAX811, MAX812
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make
changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any
particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all
liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or
specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be
validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others.
SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death
may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC
and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees
arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that
SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer.
PUBLICATION ORDERING INFORMATION
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For additional information, please contact your local
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MAX811/D
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