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 com-
ponents 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 MAX6800/MAX6801 are guaranteed to be in the cor-
rect state for VCC down to 0.7V. The MAX6802 is guaran-
teed 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
Automotive
Features
oUltra-Low 0.7V Operating Supply Voltage
oLow 4.0µA Supply Current
oPrecision Monitoring of 2.85V to 5.0V Power-
Supply Voltages
oReset Thresholds Available from 2.63V to 4.80V,
in Approximately 100mV Increments
oFully Specified over Temperature
oThree Power-On Reset Timeout Periods Available
(1ms min, 20ms min, 100ms min)
oLow Cost
oThree Available Output Structures: Push/Pull
RESET, Push/Pull RESET, Open-Drain RESET
oGuaranteed RESET/RESET Valid to VCC = 0.7V
(MAX6800/MAX6801)
oPower-Supply Transient Immunity
oNo External Components Required
o3-Pin SOT23 Package
oPin Compatible with MAX809/MAX810,
MAX6326/MAX6327/MAX6328, and
MAX6346/MAX6347/MAX6348
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
*
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.
/V Denotes an automotive-qualified part.
Typical Operating Circuit and Pin Configuration appear
at end of data sheet.
Selector Guide appears at end of data sheet.
19-1933; Rev 3; 10/11
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE PIN- PA CK A G E
MAX6800UR_ _D_-T -40°C to +125°C 3 SOT23
MAX6800UR_ _D_/V-T -40°C to +125°C 3 SOT23
MAX6801UR_ _D_-T -40°C to +125°C 3 SOT23
MAX6801UR_ _ D_/V-T -40°C to +125°C 3 SOT23
MAX6802UR_ _D_-T -40°C to +125°C 3 SOT23
MAX6802UR_ _ D_/V-T -40°C to +125°C 3 SOT23
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(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)
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.
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX6800/MAX6801 0.7 5.5
TA = 0°C to +125°CMAX6802 1.0 5.5
MAX6800/MAX6801 0.78 5.5
Supply Voltage Range
(Note 2) VCC
TA = -40°C to +125°CMAX6802 1.2 5.5
V
VCC = +3.0V 4 10
Supply Current ICC No load VCC = +5.0V 5 12 µA
TA = +25°CVTH
- 1.8% VTH VTH
+ 1.8%
Reset Threshold VTH MAX680_UR_ _D_-T,
Table 1
TA = - 40°C to + 125°C VTH
- 3% VTH VTH
+ 3%
V
VCC Falling Reset Delay VCC falling at 10V/ms 30 µs
MAX680_UR_ _D1-T 1 1.5 2
MAX680_UR_ _D2-T 20 30 40Reset Active Timeout Period tRP
MAX680_UR_ _D3-T 100 150 200
ms
ISINK = 50µA, VCC ≥ 1.0V 0.4
ISINK = 1.2mA, VCC ≥ 2.5V 0.3
RESET Output Low Voltage
(MAX6801/MAX6802) VOL Reset
asserted ISINK = 1.2mA, VCC ≥ 4.25V 0.4
V
IS OU RC E
= 500µA, V
C C
≥ 3.0V 0.8 x V
C C
RESET Output High Voltage
(MAX6801) VOH Reset not
asserted IS OU RC E
= 800µA, V
C C
≥ 5.0V 0.8 x V
C C
V
ISOURC E = 1µA, VCC
≥ 1.0V 0.8 x V
C C
ISOURC E = 200µA, V
CC
≥ 1.8V 0.8 x V
C C
VOH Reset
asserted ISOURC E = 800µA, V
CC ≥ 4.25V 0.8 x V
C C
ISINK = 1.2mA, V
CC
≥ 3.0V 0.3
RESET Output Voltage
(MAX6800)
VOL Reset not
asserted ISINK = 3.2mA, V
CC
≥ 5.0V 0.4
V
RESET Output Leakage Current
(MAX6802) VCC > VTH, RESET not asserted 0.5 µA
Note 1: All parts are production tested at TA= +25°C. Overtemperature limits are guaranteed by design and not production tested.
Note 2: ISOURCE for the MAX6800 is I00nA. ISINK for the MAX6801 is 100nA. ISINK for the MAX6802 is 50µA.
3-Pin, Low-Power
µP Reset Circuits
_______________________________________________________________________________________
3
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)
ICC (μA)
VCC = +5.0V
VCC = +3.3V
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
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
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
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 = 100µA
RESET ASSERTED
(MAX6800)
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 = 500µA
RESET ASSERTED
MAX6801/MAX6802
Typical Operating Characteristics
(Reset not asserted, TA= +25°C, unless otherwise noted.)
MAX6800/MAX6801/MAX6802
Pin Description
PIN
NAME FUNCTION
MAX6800 MAX6801/
MAX6802
1 1 GND Ground
— 2 RESET
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
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
4 _______________________________________________________________________________________
VCC
VCC
GND
MAX6802
RESET
VCC
GND
RESET
MOTOROLA
68HCXX
μP
100kΩ
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 bidirec-
tional 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 maxi-
mum pulse width that a negative-going VCC transient may
typically have without issuing a reset signal. As the ampli-
tude of the transient increases, the maximum allowable
pulse width decreases.
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
TOP VIEW
1
2
3VCC
RESET (RESET)
MAX6800
MAX6801
MAX6802
SOT23-3
( ) ARE FOR MAX6800
GND
Pin Configuration
Figure 2. Ensuring Reset Valid Down to VCC = 0V
VCC
GND
MAX6801
RESET
100kΩ
(a)
VCC
GND
MAX6800
RESET
100kΩ*
(b)
*ASSUMES HIGH-Z RESET INPUT TO THE μP
MAX6801
VCC
VCC
RESET RESET
GND
VCC
GND
μP
Typical Operating Circuit
3-Pin, Low-Power
µP Reset Circuits
_______________________________________________________________________________________ 5
MAX6800/MAX6801/MAX6802
Table 1. Factory-Trimmed Reset Thresholds
TA = +25°CT
A = -40°C to +125°C
RESET
THRESHOLD
SUFFIX 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 4.830 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
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 cur-
rents, holding RESET low (Figure 2a). The pulldown
resistor value is not critical; 100kΩis 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 100kΩpullup 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 out-
put, 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 recommend-
ed for applications where the RESET pin is required to
be valid down to VCC = 0V.
PROCESS: BiCMOS
Chip Information
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
6 _______________________________________________________________________________________
*
Sample stock is generally held on all standard versions.
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 Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.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.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
3 SOT23 U3-1 21-0051 90-0179
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim 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.
7
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© 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
3 10/11 Added automotive-qualified part information to Ordering Information.1
