19-1867; Rev 1; 1/02
Dual Ultra-Low-Voltage SOT23 µP Supervisors
with Manual Reset and Watchdog Timer
General Description
The MAX6826–MAX6831 are ultra-low-voltage micro-
processor (µP) supervisory circuits designed to monitor
two power supplies and have manual reset and watch-
dog input functions. These devices assert a system reset
if any of the monitored supplies fall below the prepro-
grammed thresholds, and maintain reset for a minimum
timeout period after the supplies rise above the threshold.
Microprocessor supervisors significantly improve system
reliability and accuracy compared to separate ICs or dis-
crete components. These devices monitor primary volt-
ages from +1.8V to +5.0V and secondary voltages from
+0.9V to +2.5V. These devices are guaranteed to be in
the correct state for V
CC
down to +1.0V.
A variety of preprogrammed reset threshold voltages
are available (see
Threshold Suffix Guide).
The devices
include manual reset and watchdog inputs. The
MAX6829/MAX6830/MAX6831 provide a factory-
trimmed threshold to monitor a 2nd voltage down to
+0.9V. The MAX6826/MAX6829 have a push-pull
RESET,
the MAX6827/MAX6830 have a push-pull
RESET and the MAX6828/MAX6831 have an open-drain
RESET.
The MAX6826/MAX6827/MAX6828 have an aux-
iliary monitor that allows user adjustable input to monitor
voltages down to +0.6V. See
Selector Guide
for func-
tions available.
Features
o
Monitor Primary V
CC
Supplies from +1.8V
to +5.0V and Secondary V
CC2
Supplies
from +0.9V to +2.5V
o
User Adjustable RESET IN Down to +0.63V
(MAX6826/MAX6827/MAX6828)
o
140ms (min) Reset Timeout Delay
o
1.6s Watchdog Timeout Period
o
Manual Reset Input
o
Three Reset Output Options
Push-Pull
RESET
Push-Pull RESET
Open-Drain
RESET
o
Guaranteed Reset Valid Down to V
CC
= +1.0V
o
Immune to Short Negative V
CC
Transients
o
No External Components
o
Small 6-pin SOT23 Packages
MAX6826–MAX6831
Ordering Information
PART
†
MAX6826_UT-T
MAX6827_UT-T
MAX6828_UT-T
MAX6829_
_UT-T
MAX6830_
_UT-T
MAX6831_
_UT-T
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
________________________Applications
Portable/Battery-
Powered Equipment
Embedded Controllers
Intelligent Instruments
Automotive Systems
Critical µP Monitoring
Multivoltage Systems
Pin Configuration
TOP VIEW
RESET(RESET)
1
6
V
CC
†
Insert the desired suffix letter (from Standard Versions table) into
the blanks to complete the part number.
Standard Versions Table*
MAX6826/MAX6827/MAX6828
L
S
5
RESET IN/V
CC2
GND
2
MAX6826–
MAX6831
R
Z
V
MR
3
4
WDI
SOT23-6
(RESET) MAX6827/MAX6830 ONLY
RESET IN FOR MAX6826/MAX6827/MAX6828 ONLY
V
CC2
FOR MAX6829/MAX6830/MAX6831 ONLY
*Samples are typically available for standard versions only.
The MAX6826/MAX6827/MAX6828 require a 2.5k minimum
order increment for all versions. Contact factory for availability.
Typical Operating Circuit appears at end of data sheet.
Threshold Suffix Guide appears at end of data sheet.
Standard Versions Table continued at end of data sheet.
Selector Guide appears at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Dual Ultra-Low-Voltage SOT23 µP Supervisors
with Manual Reset and Watchdog Timer
MAX6826–MAX6831
ABSOLUTE MAXIMUM RATINGS
V
CC
, V
CC2
to GND.................................................-0.3V to +6.0V
Open-Drain
RESET................................................-0.3V
to +6.0V
Push-Pull
RESET,
RESET............................-0.3V to (V
CC
+ 0.3V)
MR,
WDI, RESET IN....................................-0.3V to (V
CC
+ 0.3V)
Input Current (V
CC
) .............................................................20mA
Output Current (RESET, RESET).........................................20mA
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23 (derate 8.7mW/°C above +70°C)..............696mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+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
= +4.5V to +5.5V for MAX68_ _L/M, V
CC
= +2.7V to +3.6V for MAX68_ _T/S/R, V
CC
= +2.1V to +2.75V for MAX68_ _Z/Y,
V
CC
= +1.53V to +2.0V for MAX68_ _W/V; T
A
= -40°C to +125°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
SYMBOL
V
CC
CONDITIONS
T
A
= 0°C to +85°C
T
A
= -40°C to +125°C
V
CC
= +5.5V,
no load
I
CC
V
CC
= +3.6V,
no load
V
CC2
≤
+2.5V
MAX68_ _L
MAX68_ _M
MAX68_ _T
MAX68_ _S
V
CC
Reset Threshold
(V
CC
Falling)
V
TH
MAX68_ _R
MAX68_ _Z
MAX68_ _Y
MAX68_ _W
MAX68_ _V
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
4.50
4.47
4.25
4.22
3.00
2.97
2.85
2.83
2.55
2.53
2.25
2.24
2.12
2.11
1.62
1.61
1.52
4.63
4.63
4.38
4.38
3.08
3.08
2.93
2.93
2.63
2.63
2.32
2.32
2.19
2.19
1.67
1.67
1.58
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
7
MIN
1.0
1.2
10
TYP
MAX
5.5
5.5
20
30
16
25
2
4.75
4.78
4.50
4.53
3.15
3.17
3.00
3.02
2.70
2.72
2.38
2.40
2.25
2.26
1.71
1.72
1.62
V
µA
µA
UNITS
V
V
CC
Supply Current
MR
and WDI Unconnected
V
CC2
Supply Current
2
_______________________________________________________________________________________
Dual Ultra-Low-Voltage SOT23 µP Supervisors
with Manual Reset and Watchdog Timer
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.5V to +5.5V for MAX68_ _L/M, V
CC
= +2.7V to +3.6V for MAX68_ _T/S/R, V
CC
= +2.1V to +2.75V for MAX68_ _Z/Y,
V
CC
= +1.53V to +2.0V for MAX68_ _W/V; T
A
= -40°C to +125°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
Z
Y
W
V
I
V
CC2
Reset Threshold
V
TH2
H
G
F
E
D
Reset Threshold Temperature
Coefficient
Reset Threshold Hysteresis
RESET IN Threshold
RESET IN Hysteresis
RESET IN Input Current (Note 2)
V
CC
to Reset Output Delay
RESET IN to Reset Output Delay
Reset Timeout Period
t
RP
I
RSTIN
t
RD
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
V
CC
= V
TH
to (V
TH
- 100mV)
V
RSTIN
= V
RSTINTH
to (V
RSTINTH
- 30mV)
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
V
CC
≥
1.0V, I
SINK
= 50µA, reset asserted,
T
A
= 0°C to +85°C
V
OL
V
CC
≥
1.2V, I
SINK
= 100µA, reset asserted
V
CC
≥
2.55V, I
SINK
= 1.2mA, reset asserted
V
CC
≥
4.25V, I
SINK
= 3.2mA, reset asserted
140
100
-25
-100
20
15
200
280
320
0.3
0.3
0.3
0.4
V
V
RSTINTH
V
RSTINTH
falling
T
A
= 0°C to +85°C
T
A
= -40°C to +125°C
0.615
0.610
2.5
+25
+100
CONDITIONS
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
MIN
2.244
2.238
2.119
2.113
1.615
1.611
1.525
1.521
1.346
1.343
1.271
1.268
1.077
1.074
1.017
1.014
0.808
0.806
0.762
0.761
TYP
2.313
2.313
2.188
2.188
1.665
1.665
1.575
1.575
1.388
1.388
1.313
1.313
1.110
1.110
1.050
1.050
0.833
0.833
0.788
0.788
60
2 x V
TH
0.630
0.645
0.650
MAX
2.381
2.388
2.257
2.263
1.715
1.719
1.625
1.629
1.429
1.433
1.354
1.358
1.143
1.146
1.083
1.086
0.858
0.860
0.813
0.815
ppm/°C
mV
V
mV
nA
µs
µs
ms
V
UNITS
MAX6826–MAX6831
RESET
Output LOW
(Push-Pull or Open-Drain)
_______________________________________________________________________________________
3
Dual Ultra-Low-Voltage SOT23 µP Supervisors
with Manual Reset and Watchdog Timer
MAX6826–MAX6831
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.5V to +5.5V for MAX68_ _L/M, V
CC
= +2.7V to +3.6V for MAX68_ _T/S/R, V
CC
= +2.1V to +2.75V for MAX68_ _Z/Y,
V
CC
= +1.53V to +2.0V for MAX68_ _W/V; T
A
= -40°C to +125°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
RESET
Output HIGH
(Push-Pull Only)
Open-Drain
RESET
Output
Leakage Current (Note 1)
SYMBOL
V
OH
CONDITIONS
V
CC
≥
1.8V, I
SOURCE
= 200µA, reset not asserted
MIN
0.8
✕
V
CC
V
TYP
MAX
UNITS
V
CC
≥
3.15V, I
SOURCE
= 500µA, reset not asserted 0.8
✕
V
CC
V
CC
≥
4.75V, I
SOURCE
= 800µA, reset not asserted 0.8
✕
V
CC
I
LKG
RESET
not asserted
V
CC
≥
1.0V, I
SOURCE
= 1µA, reset asserted,
T
A
= 0°C to +85°C
0.8
✕
V
CC
0.8
✕
V
CC
0.8
✕
V
CC
0.8
✕
V
CC
1.0
µA
RESET Output HIGH
(Push-Pull Only)
V
OH
V
CC
≥
1.50V, I
SOURCE
= 100µA, reset asserted
V
CC
≥
2.55V, I
SOURCE
= 500µA, reset asserted
V
CC
≥
4.25V, I
SOURCE
= 800µA, reset asserted
V
CC
≥
1.8V, I
SINK
= 500µA, reset asserted
V
0.3
0.3
0.3
0.3
✕
V
CC
0.7
✕
V
CC
1
100
200
25
50
1.6
75
2.4
2.60
0.3
✕
V
CC
0.7
✕
V
CC
V
RESET Output LOW
(Push-Pull Only)
MANUAL RESET INPUT
MR
Input voltage
MR
Minimum Input Pulse
MR
Glitch Rejection
MR
to Reset Delay
MR
Pullup Resistance
WATCHDOG INPUT
Watchdog Timeout Period
WDI Pulse Width (Note 2)
WDI Input Voltage
WDI Input Current
V
OH
V
CC
≥
3.15V, I
SINK
= 1.2mA, reset asserted
V
CC
≥
4.75V, I
SINK
= 3.2mA, reset asserted
V
IL
V
IH
V
µs
ns
ns
kΩ
t
WD
t
WDI
V
IL
V
IH
I
WDI
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
1.12
0.80
50
s
ns
V
µA
WDI = V
CC
, time average
WDI = 0, time average
-20
120
-15
160
Note 1:
Over-temperature limits are guaranteed by design and not production tested. Devices tested at +25°C.
Note 2:
Guaranteed by design and not production tested.
4
_______________________________________________________________________________________
Dual Ultra-Low-Voltage SOT23 µP Supervisors
with Manual Reset and Watchdog Timer
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
MAX6826–MAX6831
SUPPLY CURRENT
vs. TEMPERATURE
MAX6826 toc01
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6826 toc02
V
CC
TO RESET OUTPUT DELAY
vs. TEMPERATURE
V
CC
FALLING, V
CC
= V
TH
- 100mV
MAX6826 toc03
13
12
11
SUPPLY CURRENT (µA)
10
9
8
7
6
5
4
3
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
V
CC
= +3.3V, S VERSION
V
CC
= +1.8V, V VERSION
V
CC
= +5V, L VERSION
250
240
RESET TIMEOUT PERIOD (ms)
230
220
210
200
190
180
170
160
150
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
35
30
PROPAGATION DELAY (µs)
25
20
15
10
5
0
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
WATCHDOG TIMEOUT PERIOD
vs. TEMPERATURE
MAX6826 toc04
NORMALIZED RESET THRESHOLD
DELAY vs. TEMPERATURE
MAX6826 toc05
MAXIMUM V
CC
TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6826 toc06
2.0
1.9
WATCHDOG TIMEOUT PERIOD (s)
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
1.06
1.04
RESET THRESHOLD (V)
1.02
1.00
0.98
0.96
0.94
-40 -20
120
100
80
60
40
20
0
TRANSIENT DURATION (µs)
RESET OCCURS
ABOVE CURVE
0
20
40
60
80
100 120
0
20 40 60 80 100 120 140 160 180 200
RESET THRESHOLD OVERDRIVE (mV), V
TH
- V
CC
TEMPERATURE (°C)
V
RSTIN
TO RESET OUTPUT DELAY
vs. TEMPERATURE
MAX6826 toc07
MAXIMUM V
RSTIN
TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
90
TRANSIENT DURATION (µs)
80
70
60
50
40
30
20
10
RESET OCCURS
ABOVE CURVE
MAX6826 toc08
25
V
RSTIN
FALLING
V
RSTIN
= V
RSTINTH
- 30mV
100
PROPAGATION DELAY (µs)
20
15
10
5
0
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
0
0
20 40 60 80 100 120 140 160 180 200
RESET THRESHOLD OVERDRIVE (mV), V
RSTINTH
- V
RSTIN
_______________________________________________________________________________________
5
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