General Description
The MAX6800/MAX6801/MAX6802 microprocessor (μP)
supervisory circuits monitor the power supplies in 2.85V to
5.0V μP and digital systems. They increase circuit reliability
and reduce cost by eliminating external components and
adjustments.
These devices perform a single function—they assert a
reset signal whenever the VCC supply voltage declines
below a preset threshold, keeping it asserted for a preset
timeout period after VCC has risen above the reset
threshold. The only difference among the three devices
is their output. The MAX6801 (push/pull) and MAX6802
(open-drain) have an active-low RESET output, while the
MAX6800 (push/pull) has an active-high RESET output.
The devices are guaranteed to be in the correct state for
VCC down to 0.7V. The MAX6802 is guaranteed to be in
the correct state for VCC down to 1.0V.
The reset comparator in these ICs is designed to ignore
fast transients on VCC. Reset thresholds are factory-
trimmable between 2.63V and 4.80V, in approximately
100mV increments. These devices are available with
a 1ms (min), 20ms (min), or 100ms (min) reset pulse
width. Ideal for space-critical applications, the MAX6800/
MAX6801/MAX6802 come packaged in a 3-pin SOT23.
For a lower threshold voltage version, see the MAX6332/
MAX6333/MAX6334.
Applications
Computers
Controllers
Intelligent Instruments
Critical μP/μC Power Monitoring
Portable/Battery-Powered Equipment
Benets and Features
Ultra-Low 0.7V Operating Supply Voltage
Low 4.0μA Supply Current
Precision Monitoring of 2.85V to 5.0V Power-
Supply Voltages
Reset Thresholds Available from 2.63V to 4.80V, in
Approximately 100mV Increments
Fully Specified over Temperature
Three Power-On Reset Timeout Periods Available
(1ms min, 20ms min, 100ms min)
Low Cost
Three Available Output Structures: Push/Pull
RESET, Push/Pull RESET, Open-Drain RESET
Guaranteed RESET/RESET Valid to VCC = 0.7V
(MAX6800/MAX6801)
Power-Supply Transient Immunity
No External Components Required
3-Pin SOT23 Package
Pin-Compatible with MAX809/MAX810,
MAX6326/MAX6327/MAX6328, and
MAX6346/MAX6347/MAX6348
19-1933; Rev 5; 2/16
Selector Guide (Standard Versions*) appears at end of data sheet.
Typical Operating Circuit
MAX6801
VCC
VCC
RESET RESET
GND
VCC
GND
µP
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
Terminal Voltage (with respect to GND)
VCC ...................................................................... -0.3V to +6V
Push/Pull RESET, RESET .................... -0.3V to (VCC + 0.3V)
Open-Drain RESET .............................................-0.3V to +6V
Input Current (VCC) ............................................................ 20mA
Output Current (RESET, RESET) ......................................20mA
Continuous Power Dissipation (TA = +70°C)
3-Pin SOT23 (derate 4mW/°C above +70°C) .............320mW
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
Soldering Temperature (reflow) ....................................... +300°C
Lead (Pb)-free packages ............................................. +260°C
Package containing lead (Pb) ..................................... +240°C
(VCC = full range, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +5.0V and TA = +25°C, reset not
asserted.) (Note 1)
Note 1: All parts are production tested at TA = +25°C. Overtemperature limits are guaranteed by design and not production tested.
Note 2: I
SOURCE for the MAX6800 is 100nA. ISINK for the MAX6801 is 100nA. ISINK for the MAX6802 is 50μA.
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range
(Note 2) VCC
TA = 0°C to +125°C MAX6800/MAX6801 0.7 5.5
V
MAX6802 1.0 5.5
TA = -40°C to +125°C MAX6800/MAX6801 0.78 5.5
MAX6802 1.2 5.5
Supply Current ICC No load VCC = +3.0V 4 10 µA
VCC = +5.0V 5 12
Reset Threshold VTH MAX680_UR_ _D_-T,
Table 1
TA = +25°C VTH
- 1.8% VTH
VTH
+ 1.8% V
TA = -40°C to +125°C VTH
- 3% VTH
VTH
+ 3%
VCC Falling Reset Delay VCC falling at 10V/ms 30 µs
Reset Active Timeout Period tRP
MAX680_UR_ _D1-T 1 1.5 2
msMAX680_UR_ _D2-T 20 30 40
MAX680_UR_ _D3-T 100 150 200
RESET Output Low-Voltage
(MAX6801/MAX6802) VOL Reset
asserted
ISINK = 50µA, VCC ≥ 1.0V 0.4
VISINK = 1.2mA, VCC ≥ 2.5V 0.3
ISINK = 1.2mA, VCC ≥ 4.25V 0.4
RESET Output High-Voltage
(MAX6801) VOH Reset not
asserted
ISOURCE = 500µA, VCC ≥ 3.0V 0.8 x VCC V
ISOURCE = 800µA, VCC ≥ 5.0V 0.8 x VCC
RESET Output Voltage
(MAX6800)
VOH Reset
asserted
ISOURCE = 1µA, VCC 1.0V 0.8 x VCC
V
ISOURCE = 200µA, VCC 1.8V 0.8 x VCC
ISOURCE = 800µA, VCC 4.25V 0.8 x VCC
VOL Reset not
asserted
ISINK = 1.2mA, VCC 3.0V 0.3
ISINK = 3.2mA, VCC 5.0V 0.4
RESET Output Leakage Current
(MAX6802) VCC > VTH, RESET not asserted 0.5 µA
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
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(Reset not asserted, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics
0.950
0.980
0.970
0.960
1.000
0.990
1.040
1.030
1.020
1.010
1.050
-50 -25 0 25 50 75 100 125
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6800/01/02 toc02
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
80
60
40
20
0
1.0 1.5 2.0 2.5 3.0
RESET (VOL)
vs. SUPPLY VOLTAGE
MAX6800/01/02 toc03
VCC (V)
OUTPUT VOLTAGE LOW (mV)
TA = +125°C
TA = +85°C
TA = +25°C
TA = -40°C
VTH = 2.93V
ISINK = 500mA
RESET ASSERTED
MAX6801/MAX6802
100
75
50
25
0
1.0 2.01.5 2.5 3.0
RESET (VOH)
vs. SUPPLY VOLTAGE
MAX6800/01/02 toc04
VCC (V)
OUTPUT VOLTAGE HIGH (VCC - VOH) (mV)
TA = +25°C
TA = -40°C
TA = +125°C
TA = +85°C
VTH = 2.93V
ISOURCE = 100A
RESET ASSERTED
(MAX6800)
100 1000
0
100
200
400
300
500
600
0.1 1 10
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
MAX6800/01/02 toc05
RESET COMPARATOR OVERDRIVE (mV)
MAXIMUM TRANSIENT DURATION (µs)
RESET OCCURS
RESET DOES
NOT OCCUR
0
30
20
10
50
40
90
80
70
60
100
-50 -25 0 25 50 75 100 125
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
MAX6800/01/02 toc06
TEMPERATURE (°C)
PROPAGATION DELAY (µs)
VCC = FALLING AT 1V/ms
VCC = FALLING AT 10V/ms
3.0
4.0
3.5
5.0
4.5
6.0
5.5
6.5
-50 0 25-25 50 75 100 125
SUPPLY CURRENT vs. TEMPERATURE
MAX6800/01/02 toc01
TEMPERATURE (°C)
I
CC
(µA)
VCC = +5.0V
VCC = +3.3V
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
Maxim Integrated
3
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Pin Description
PIN
NAME FUNCTION
MAX6800 MAX6801/
MAX6802
1 1 GND Ground
2RESET
Active-Low Reset Output. RESET is asserted while VCC is below the reset
threshold and remains asserted for a reset timeout period (tRP) after VCC
rises above the reset threshold. RESET on the MAX6801 is push/pull.
RESET on the MAX6802 is open-drain.
2 RESET
Active-High Reset Output. RESET is asserted while VCC is below the reset
threshold and remains asserted for a reset timeout period (tRP) after VCC
rises above the reset threshold. RESET on the MAX6800 is push/pull.
3 3 VCC Supply Voltage Input
Pin Conguration
TOP VIEW
1
2
3VCC
RESET (RESET)
MAX6800
MAX6801
MAX6802
SOT23-3
( ) ARE FOR MAX6800
GND
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
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Applications Information
Interfacing to μPs with Bidirectional
Reset Pins
Since the RESET output on the MAX6802 is open-
drain, this device interfaces easily with μPs that have
bidirectional reset pins, such as the Motorola 68HC11.
Connecting the μP supervisor’s RESET output directly to
the microcontroller’s (μC’s) RESET pin with a single pullup
resistor allows either device to assert reset (Figure 1).
Negative-Going VCC Transients
In addition to issuing a reset to the μP during
power-up, power-down, and brownout conditions, these
devices are relatively immune to short-duration, negative-
going VCC transients (glitches). The Typical Operating
Characteristics show the Maximum Transient Duration
vs. Reset Comparator Overdrive graph. The graph shows
the maximum pulse width that a negative-going VCC
transient may typically have without issuing a reset signal.
As the amplitude of the transient increases, the maximum
allowable pulse width decreases.
Ensuring a Valid Reset Output Down to
VCC = 0V
When VCC falls below 1V and approaches the minimum
operating voltage of 0.7V, push/pull-structured reset
sinking (or sourcing) capabilities decrease drastically.
High-impedance CMOS-logic inputs connected to the
RESET pin can drift to indeterminate voltages. This does
not present a problem in most cases, since most μPs and
circuitry do not operate when VCC drops below 1V. For
the MAX6801 application, where RESET must be valid
down to 0V, adding a pulldown resistor between RESET
and GND removes stray leakage currents, holding RESET
low (Figure 2a). The pulldown resistor value is not critical;
100kΩ is large enough not to load RESET and small
enough to pull it low. For the MAX6800 application, where
RESET must be valid to VCC = 0V, a 100kΩ pullup resistor
between RESET and VCC will hold RESET high when
VCC falls below 0.7V (Figure 2b).
Since the MAX6802 has an open-drain, active-low output,
it typically uses a pullup resistor. With this device, RESET
will most likely not maintain an active condition, but will
drift to a non-active level due to the pullup resistor and
the reduced sinking capability of the open-drain device.
Therefore, this device is not recommended for applications
where the RESET pin is required to be valid down to VCC = 0V.
Figure 1. Interfacing to μPs with Bidirectional Reset Pins
VCC
VCC
GND
MAX6802
RESET
VCC
GND
RESET
MOTOROLA
68HCXX
µP
100k
Figure 2. Ensuring Reset Valid Down to VCC = 0V
VCC
GND
MAX6801
RESET
100k
(a)
VCC
GND
MAX6800
RESET
100k*
(b)
*ASSUMES HIGH-Z RESET INPUT TO THE µP
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
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Table 1. Factory-Trimmed Reset Thresholds
RESET
THRESHOLD
SUFFIX
TA = +25°C TA = -40°C to +125°C
MIN TYP (VTH)MAX MIN MAX
48 4.714 4.80 4.886 4.656 4.944
47 4.615 4.70 4.785 4.559 4.841
46 4.547 4.63 4.713 4.491 4.769
45 4.419 4.50 4.581 4.365 4.635
44 4.301 4.38 4.459 4.249 4.511
43 4.223 4.30 4.377 4.171 4.429
42 4.124 4.20 4.276 4.074 4.326
41 4.026 4.10 4.174 3.977 4.223
40 3.928 4.00 4.072 3.880 4.120
39 3.830 3.90 3.970 3.783 4.017
38 3.732 3.80 3.868 3.686 3.914
37 3.633 3.70 3.767 3.589 3.811
36 3.535 3.60 3.665 3.492 3.708
35 3.437 3.50 3.563 3.395 3.605
34 3.339 3.40 3.461 3.298 3.502
33 3.241 3.30 3.359 3.201 3.399
32 3.142 3.20 3.258 3.104 3.296
31 3.025 3.08 3.135 2.988 3.172
30 2.946 3.00 3.054 2.910 3.090
29 2.877 2.93 2.983 2.842 3.018
28 2.750 2.80 2.850 2.716 2.884
27 2.651 2.70 2.749 2.619 2.781
26 2.583 2.63 2.677 2.551 2.709
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
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*Sample stock is generally held on all standard versions.
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.
Chip Information
PROCESS: BiCMOS
Selector Guide (Standard Versions*)
PART OUTPUT STAGE NOMINAL VTH (V) MIN RESET
TIMEOUT (ms)
SOT
TOP MARK
MAX6800UR26D3-T Push/Pull RESET 2.63 100 FZIE
MAX6800UR29D3-T Push/Pull RESET 2.93 100 FZIF
MAX6800UR31D3-T Push/Pull RESET 3.08 100 FZIG
MAX6800UR44D3-T Push/Pull RESET 4.38 100 FZIH
MAX6800UR46D3-T Push/Pull RESET 4.63 100 FZII
MAX6801UR26D3-T Push/Pull RESET 2.63 100 FZIK
MAX6801UR29D3-T Push/Pull RESET 2.93 100 FZIM
MAX6801UR31D3-T Push/Pull RESET 3.08 100 FZIN
MAX6801UR44D3-T Push/Pull RESET 4.38 100 FZIO
MAX6801UR46D3-T Push/Pull RESET 4.63 100 FZIP
MAX6802UR26D3-T Open-Drain RESET 2.63 100 FZIQ
MAX6802UR29D3-T Open-Drain RESET 2.93 100 FZIR
MAX6802UR31D3-T Open-Drain RESET 3.08 100 FZIS
MAX6802UR44D3-T Open-Drain RESET 4.38 100 FZIT
MAX6802UR46D3-T Open-Drain RESET 4.63 100 FZIU
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
3 SOT23 U3-1 21-0051 90-0179
*These devices are available in factory-set VCC reset thresh-
olds from 2.63V to 4.80V, in approximately 0.1V increments.
Choose the desired reset threshold suffix from Table 1 and
insert it in the blanks following “UR” in the part number.
Factory-programmed reset timeout periods are also available.
Insert the number corresponding to the desired nominal reset
timeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) in
the blank following “D” in the part number. There are 15 stan-
dard versions with a required order increment of 2500 pieces.
Sample stock is generally held on the standard versions only
(see Selector Guide). Contact the factory for availability of non-
standard versions (required order increment is 10,000 pieces).
All devices available in tape-and-reel only.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Ordering Information
PART TEMP RANGE PIN-PACKAGE
MAX6800UR_ _D_-T -40°C to +125°C 3 SOT23
MAX6801UR_ _D_-T -40°C to +125°C 3 SOT23
MAX6802UR_ _D_-T -40°C to +125°C 3 SOT23
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
www.maximintegrated.com Maxim Integrated
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Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
310/11 Added automotive-qualied part information to Ordering Information. 1
4 3/12 Updated Factory-Trimmed Reset Thresholds table. 5
5 2/16 Updated Ordering Information table 1
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 specications 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.
MAX6800/MAX6801/
MAX6802
3-Pin, Low-Power
μP Reset Circuits
© 2016 Maxim Integrated Products, Inc.
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MAX6800UR26D3+T MAX6800UR27D1+T MAX6800UR27D2+T MAX6800UR27D3+T MAX6800UR28D1+T
MAX6800UR28D2+T MAX6800UR28D3+T MAX6800UR29D1+T MAX6800UR29D2+T MAX6800UR29D3+T
MAX6800UR30D1+T MAX6800UR30D2+T MAX6800UR30D3+T MAX6800UR31D1+T MAX6800UR31D2+T
MAX6800UR31D3+T MAX6800UR32D1+T MAX6800UR32D2+T MAX6800UR32D3+T MAX6800UR33D1+T
MAX6800UR33D2+T MAX6800UR33D3+T MAX6800UR34D1+T MAX6800UR34D2+T MAX6800UR34D3+T
MAX6800UR35D1+T MAX6800UR35D3+T MAX6800UR36D1+T MAX6800UR36D2+T MAX6800UR36D3+T
MAX6800UR37D1+T MAX6800UR37D2+T MAX6800UR37D3+T MAX6800UR38D1+T MAX6800UR38D2+T
MAX6800UR38D3+T MAX6800UR39D1+T MAX6800UR39D2+T MAX6800UR39D3+T MAX6800UR40D1+T
MAX6800UR40D2+T MAX6800UR40D3+T MAX6800UR41D1+T MAX6800UR41D2+T MAX6800UR41D3+T
MAX6800UR42D1+T MAX6800UR42D2+T MAX6800UR42D3+T MAX6800UR43D1+T MAX6800UR43D2+T
MAX6800UR43D3+T MAX6800UR44D1+T MAX6800UR44D2+T MAX6800UR44D3+T MAX6800UR45D1+T
MAX6800UR45D2+T MAX6800UR45D3+T MAX6800UR46D1+T MAX6800UR46D2+T MAX6800UR46D3+T
MAX6800UR47D1+T MAX6800UR47D2+T MAX6800UR47D3+T MAX6800UR48D1+T MAX6800UR48D2+T
MAX6800UR48D3+T MAX6801UR26D1+T MAX6801UR26D2+T MAX6801UR26D3+T MAX6801UR27D1+T
MAX6801UR27D2+T MAX6801UR27D3+T MAX6801UR28D1+T MAX6801UR28D2+T MAX6801UR28D3+T
MAX6801UR29D1+T MAX6801UR29D2+T MAX6801UR29D3+T MAX6801UR30D1+T MAX6801UR30D2+T
MAX6801UR30D3+T MAX6801UR31D1+T MAX6801UR31D2+T MAX6801UR31D3+T MAX6801UR32D1+T
MAX6801UR32D2+T MAX6801UR32D3+T MAX6801UR33D1+T MAX6801UR33D2+T MAX6801UR33D3+T
MAX6801UR34D1+T MAX6801UR34D2+T MAX6801UR34D3+T MAX6801UR35D1+T MAX6801UR35D2+T
MAX6801UR35D3+T MAX6801UR36D1+T MAX6801UR36D2+T MAX6801UR36D3+T MAX6801UR37D1+T