MAX6806/MAX6807/
MAX6808
Voltage Detectors
General Description
The MAX6806/MAX6807/MAX6808 precision voltage
detectors are ideal for accurate monitoring of power
supplies in digital systems. They provide circuit reliability
and reduce total cost by eliminating external components
and adjustments.
The MAX6806/MAX6807/MAX6808 assert a reset signal
whenever the supply voltage (VCC) falls below the factorypreset, ±2% accurate threshold. Internal hysteresis
ensures stable switching. The MAX6806/MAX6807/
MAX6808 are available in 4.6V and 2.6V thresholds (2.3V
is also available for the MAX6806 only). The MAX6806
features an active-low, push-pull RESET output; the
MAX6807 features an active-high, push-pull RESET
output; and the MAX6808 features an active-low, opendrain RESET output. RESET is valid for VCC down to 1V
(MAX6806/MAX6808), and RESET (MAX6807) is guaranteed for VCC down to 1.2V.
The MAX6806/MAX6807/MAX6808 are available in
3-pin SC70, 3-pin SOT23, 8-pin µMAX, 8-pin SO, and
4-pin SOT143 packages. The SOT143 package includes
a manual-reset input.
Features
●● Preset Reset Thresholds: 4.6V and 2.6V
(2.3V also available for MAX6806 only)
●● ±2% Accurate Reset Thresholds
●● Reset Output Available in Active-Low (MAX6806),
Active-High (MAX6807), and Open-Drain (MAX6808)
Versions
●● Immune to Power-Supply Transients
●● RESET Valid to VCC = 1.0V (MAX6806/MAX6808)
●● 35µA Supply Current
●● No External Components
●● Manual Reset Available with 4-Pin SOT143 Package
●● Miniature 3-Pin SC70, 3-Pin SOT23, and 4-Pin
SOT143 Packages
●● 8-Pin µMAX and 8-Pin SO Packages are Pin
Compatible with the MC33064/MC33164/
MC34064/MC34164
Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX6806XR_ _ -T
-40°C to +85°C
3 SC70
MAX6806UR_ _ -T
-40°C to +85°C
3 SOT23
MAX6806US_ _ -T
-40°C to +85°C
4 SOT143
MAX6806UA_ _
-40°C to +85°C
8 µMAX
MAX6806SA_ _
-40°C to +85°C
8 SO
Selector Guide and Pin Configurations appear at end of
data sheet.
MAX6807XR_ _ -T
-40°C to +85°C
3 SC70
MAX6807UR_ _ -T
-40°C to +85°C
3 SOT23
Typical Operating Circuit
MAX6807US_ _ -T
-40°C to +85°C
4 SOT143
MAX6807UA_ _
-40°C to +85°C
8 µMAX
MAX6807SA_ _
-40°C to +85°C
8 SO
MAX6808XR_ _ -T
-40°C to +85°C
3 SC70
MAX6808UR_ _ -T
-40°C to +85°C
3 SOT23
MAX6808US_ _ -T
-40°C to +85°C
4 SOT143
MAX6808UA_ _
-40°C to +85°C
8 µMAX
MAX6808SA_ _
-40°C to +85°C
8 SO
Applications
●●
●●
●●
●●
Computers
Controllers
Intelligent Instruments
Critical µP and µC
Power Monitoring
●● Portable/Battery●● Powered Equipment
●● Bar-Code Scanners
VCC
VCC
VCC
MAX6806
MAX6807
MAX6808
(RESET)/RESET
GND
( ) ARE FOR MAX6807
19-1421; Rev 3; 7/14
µP
RESET
INPUT
GND
* SOT23, SOT143, and SC70s are available in tape-and-reel
only, 2500 piece minimum order quantity.
Note: Insert the desired number from the Selector Guide into
the blank to complete the part number. Also see Selector Guide
for top mark for SOT23
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Absolute Maximum Ratings
VCC to GND .........................................................-0.3V to +6.0V
RESET, RESET to GND
(MAX6806/MAX6807) .............................. -0.3V to (VCC + 0.3V)
RESET to GND (MAX6808).................................-0.3V to + 6.0V
MR to GND (SOT143 package only)...................-0.3V to + 6.0V
Input Current, VCC ...........................................................±20mA
Output Current, RESET, RESET ......................................±20mA
Rate of Rise, VCC ..........................................................100V/µs
Continuous Power Dissipation (TA = +70°C)
SOT23, SOT143 (derate 4mW/°C above +70°C) .......320mW
SC70 (derate 2.17mW/°C above +70vC) ....................174mW
µMAX (derate 4.5mW/°C above +70°C) .....................362mW
SO (derate 5.9mW/°C above +70°C) ..........................471mW
Operating Temperature Range ........................... -40°C to +85°C
Storage Temperature Range............................. -65°C to +160°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
(VCC = +5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
Supply Voltage Range
VCC
Supply Current
ICC
Reset Threshold
Reset Threshold Hysteresis
RESET Output Voltage
(MAX6806/MAX6808)
VTH-
VHYST
VOL
CONDITIONS
TA = -40°C to +85°C
1.2
5.5
VCC = +3.6V, no load
35
60
VCC = +5.5V, no load
50
80
TA = +25°C
VCC falling
MAX680_ _ _46
4.508
4.60
4.692
MAX680_ _ _32
3.136
3.20
3.264
MAX680_ _ _26
2.548
2.60
2.652
MAX680_ _ _23
2.254
2.30
2.346
0.02
VTH-
0.03
VTH-
TA = +25°C, Figure 2
ISINK = 20µA, VCC = 1.0V
0.3
ISINK = 1.0mA, VCC = 2.0V
0.4
RESET Output Leakage Current
IOH
VCC = 5.5V, RESET deasserted
(MAX6808 only)
RESET Output Voltage
(MAX6807)
VOH
1
ISOURCE = 20µA, VCC = 1.2V
0.8 VCC
ISOURCE = 400µA, VCC = 2.0V
0.8 VCC
MR Input Threshold
VIH
40
VCC > VTH+
µA
V
V
V
µA
0.4
VCC falling at 1mV/µs
VIL
V
V
ISINK = 3.2mA, VCC = 5.0V
RMR
UNITS
0.8 VCC
Reset Threshold Tempco
MR Pulldown Resistance
MAX
5.5
ISOURCE = 2.0mA, VCC = 5.0V
(MAX6806 only)
VCC to Reset Delay (Note 2)
TYP
1.0
VOH
VOL
MIN
TA = 0°C to +70°C
30
µs
30
ppm/°C
80
120
0.6
0.7 VCC
kW
V
Note1: All devices are 100% production tested at TA = +25°C, and are guaranteed by design for TA = TMIN to TMAX, as specified.
Note 2: RESET output for MAX6806/MAX6808, RESET output for MAX6807.
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Maxim Integrated │ 2
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. TEMPERATURE
35
41
VCC = 3.3V
30
25
VCC = 1.8V
20
15
10
0
-60
-30
0
30
60
90
39
37
35
33
31
29
VCC = 1.0V
5
VOD = VTH- - VCC = 100mV
VCC FALLING AT 1mV/µS
43
27
25
120
-60 -45 -30 -15 0 15 30 45 60 75 90 105 120135
TEMPERATURE (°C)
TEMPERATURE (°C)
POWER-UP RESET DELAY
vs. TEMPERATURE
11
DELAY TIME (µs)
10
1.0100
NORMALIZED RESET THRESHOLD
VOD = VCC - VTH+
MAX6806/7/8-03
12
9
VOD = 50mV
8
7
VOD = 100mV
6
5
4
VOD = 200mV
-60
-30
0
30
60
90
1.0080
1.0060
VCC RISING (VTH+)
1.0040
1.0020
1.0000
0.9980
0.9960
VCC FALLING (VTH-)
0.9940
0.9920
0.9900
120
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
MAX6806/7/8-04
40
45
MAX6806/7/8toc02
VCC = 5.0V
RESET DELAY (µs)
SUPPLY CURRENT (µA)
45
MAX6806/7/8-01
50
POWER-DOWN RESET DELAY
vs. TEMPERATURE
-40 -30 -15
0
15
30
45
60
75
85
TEMPERATURE (°C)
TEMPERATURE (°C)
Pin Description
PIN
SOT23/SC70
1
SOT143
1
2
4
µMAX/SO
NAME
FUNCTION
RESET
Active-Low Reset Output (MAX6806/MAX6808). RESET remains low
while VCC is below the reset-threshold voltage or while MR is held high.
RESET
Active-High Reset Output (MAX6807). RESET remains high while VCC
is below the reset-threshold voltage or while MR is held high.
1
4
GND
Ground
3
3
2
VCC
Supply Voltage Input
—
2
—
MR
Active-High Manual Reset Input. Internal 80kW resistor to GND.
—
—
3,5–8
N.C.
Not Internally Connected
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Maxim Integrated │ 3
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Detailed Description
Manual-Reset Input
Reset Output
The MAX6806 voltage detector features an active-low,
push-pull RESET output, while the MAX6807 features an
active-high, push-pull RESET output. Unlike microprocessor (µP) supervisory circuits that offer a reset timeout
period, the MAX6806 and MAX6807 RESET goes high
and RESET goes low virtually immediately once VCC
exceeds the reset threshold. If a brownout occurs (VCC
falls below the reset threshold), RESET goes low and
RESET goes high. RESET is guaranteed to be a logic
low for VCC ≥ 1V and RESET is guaranteed to be a logic
high for VCC ≥ 1.2V.
The MAX6808 features an active-low, open-drain RESET
output. The output sinks current when VCC falls below
the reset threshold. Connect a pullup resistor from
RESET to any supply voltage up to 6V (Figure 1). Select
a resistor value large enough to provide a logic low and
small enough to provide a logic high while supplying all
input and leakage currents connected to the RESET
line. A 100kΩ resistor is sufficient in applications driving
high-impedance loads.
The manual reset input (MR, 4-pin SOT143 package) can
also initiate a reset (see Manual Reset Input section).
+3.3V
+5.0V
Many applications require manual-reset capabilities,
allowing an operator, a test technician, or external logic
circuitry to initiate a reset. A logic high on MR asserts
a reset and remains asserted while MR is high. This
input has an 80kΩ pulldown resistor, so the input can be
left unconnected if not used. Connect a normally open
momentary switch from MR to VCC to create a manual-reset function. 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 noise immunity.
Hysteresis
The MAX6806/MAX6807/MAX6808 feature internal
hysteresis that creates two trip points: one for the rising
supply voltage and one for the falling supply voltage
(Figure 2). The hysteresis prevents the output from
oscillating (chattering) when VCC is near the reset
threshold.
Reset Threshold Accuracy
The MAX6806/MAX6807/MAX6808 are ideal for
sys-tems using a 5V ±5%, 3V ±5%, or 2.5V ±5% power
supply with ICs specified for 5V ±10%, 3V ±10%, or
2.5V ±10%, respectively. The reset is guaranteed to
assert after the power supply falls out of regulation,
but before power drops below the minimum specified
oper-ating voltage range for the system ICs.
VTH+
HYST
VCC
VCC
MAX6808
100kΩ
VHYST = VTH+ - VTH-
VTH-
VOH
5V SYSTEM
RESET
(MAX6806/MAX6808)
VOL
RESET
VOH
GND
GND
RESET
(MAX6807)
Figure 1. The MAX6808 Open-Drain RESET Output Allows Use
with Multiple Supplies
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VOL
Figure 2. Input and Output Waveforms with VCC Varied
Maxim Integrated │ 4
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Applications Information
Ensuring a Valid Reset Output Down to
VCC = Ground
Negative-Going VCC Transients
In addition to asserting a reset signal during power-up,
power-down, and brown-out conditions, the MAX6806/
MAX6807/MAX6808 are immune to short-duration, negative-going VCC transients.
Figure 3 displays typical transient durations vs. reset-comparator overdrive for which the MAX6806/MAX6807/
MAX6808 do not generate a reset pulse. The graph was
generated using a negative-going pulse applied to VCC,
starting 0.5V above the actual reset threshold and ending
below it by the magnitude indicated (reset-comparator
overdrive). The graph indicates the maximum pulse width
a negative-going VCC transient can have without causing
a reset pulse. As the magnitude of the transient increases
(goes further below the reset threshold), the maximum
allowable pulse width decreases. A 0.1µF capacitor
mounted as close as possible to VCC provides additional
transient immunity.
When VCC falls below 1V, the MAX6806/MAX6808
RESET output no longer sinks current—it becomes
an open circuit. Therefore, high-impedance CMOS
logic inputs connected to RESET can drift to
undetermined voltages. This presents no problem in most
applications, since most circuitry is inoperative when
VCC is below 1V. In applications where RESET must
be valid down to ground, add a pulldown resistor to
RESET so any stray leakage currents flow to ground,
holding RESET low (Figure 4). Select R1 to be large
enough not to load RESET and small enough to pull
RESET to ground. For most applications, 100kΩ will not
load RESET and will pull RESET to ground. Similarly,
if RESET (MAX6807) must be valid below 1.2V, add a
pullup resistor to RESET.
MAXIMUM TRANSIENT DURATION (µs)
80
TA = +25°C
70
VCC
VCC
60
MAX6806
50
40
MAX680
46
RESET
30
20
MAX6807
R1
100kΩ
RESET
R1
100kΩ
10
100
1000
GND
GND
RESET COMPARATOR OVERDRIVE, VTH- - VCC (mV)
Figure 3. Maximum Transient Duration without Causing a Reset
Pulse vs. Reset Comparator Overdrive
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Figure 4. RESET / RESET Valid to VCC = Ground Circuit
Maxim Integrated │ 5
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Interfacing to µPs with Bidirectional
Reset Pins
µPs with bidirectional reset pins (such as the Motorola
68HC11 series) can contend with push-pull RESET
outputs, resulting in indeterminate logic levels. Use the
MAX6808 with the open-drain RESET when interfacing
to this type of controller.
VCC
VCC
VCC
MAX6808
RESET
GND
4.7kΩ
µP
RESET
GND
Figure 5. Interfacing to μPs with Bidirectional Reset I/O
Selector Guide
TOP MARK
NOMINAL VTH- (V)†
MAX6806SA46
PART
RESET OUTPUT
—
4.6
MAX6806SA26
—
2.6
MAX6806SA23
—
2.3
MAX6806UA46
—
4.6
MAX6806UA26
—
2.6
MAX6806UA23
—
2.3
MAX6806UR46-T
FZDP
4.6
FZDQ
2.6
FZDR
2.3
MAX6806US46-T
KABT
4.6
MAX6806US26-T
KABU
2.6
MAX6806US23-T
KABV
2.3
MAX6806XR46-T
AAA
4.6
MAX6806XR26-T
AAB
2.6
MAX6806XR23-T
AAC
2.3
MAX6806UR26-T
MAX6806UR23-T
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Active-Low, Push-Pull
Maxim Integrated │ 6
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Selector Guide (continued)
TOP MARK
NOMINAL VTH- (V) †
MAX6807SA46
PART
—
4.6
MAX6807SA26
—
2.6
MAX6807UA46
—
4.6
MAX6807UA26
—
2.6
FZDS
4.6
FZDT
2.6
MAX6807US46-T
KABW
4.6
MAX6807US26-T
KABX
2.6
MAX6807XR46-T
AAD
4.6
MAX6807XR26-T
MAX6807UR46-T
MAX6807UR26-T
RESET OUTPUT
Active-High, Push-Pull
AAE
2.6
MAX6808SA46
—
4.6
MAX6808SA32
—
3.2
MAX6808SA26
—
2.6
MAX6808UA46
—
4.6
MAX6808UA32
—
3.2
MAX6808UA26
—
2.6
FZDU
4.6
MAX6808UR46-T
MAX6808UR32-T
Active-Low, Open-Drain
FZFL
3.2
FZDV
2.6
MAX6808US46-T
KABY
4.6
MAX6808US32-T
KACC
3.2
MAX6808US26-T
KABZ
2.6
MAX6808XR46-T
AAF
4.6
MAX6808XR32-T
ACD
3.2
MAX6808XR26-T
AAG
2.6
MAX6808UR26-T
Other voltage thresholds may be available. Contact factory for availability.
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Maxim Integrated │ 7
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Pin Configurations
TOP VIEW
(RESET)/RESET
1
MAX6806
MAX6807
MAX6808
GND 2
SOT23/SC70
( ) ARE FOR MAX6807
Chip Information
TRANSISTOR COUNT: 72
(RESET)/RESET
3
1
VCC
MAX6806
MAX6807
MAX6808
8
N.C.
7
N.C.
VCC
2
N.C.
3
6
N.C.
GND
4
5
N.C.
(RESET)/RESET
GND
3
VCC
MAX6806
MAX6807
MAX6808
MR
2
SOT143
µMAX/SO
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.
PACKAGE
TYPE
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4
1
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
3 SC70
X3-2
21-0075
90-0208
3 SOT23
U3-1
21-0051
90-0179
4 SOT143
U4-1
21-0052
90-0183
8 SO
—
21-0041
—
8 μMAX
—
21-0036
—
Maxim Integrated │ 8
MAX6806/MAX6807/
MAX6808
Voltage Detectors
Revision History
REVISION
NUMBER
REVISION
DATE
3
7/14
PAGES
CHANGED
DESCRIPTION
No /V OPNs; removed Automotive reference from Applications section;
updated Package Information
1, 9–13
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
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 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.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
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