19-1952; Rev 3; 12/05
Low-Voltage, SOT23 µP Supervisors with Power-
Fail In/Out, Manual Reset, and Watchdog Timer
General Description
The MAX6701–MAX6708 microprocessor (µP) supervisory
circuits reduce the complexity and components required
to monitor power-supply functions in µP systems. These
devices significantly improve system reliability and accu-
racy compared to separate ICs or discrete components.
The MAX6701–MAX6708 family provides four functions:
a reset output during power-up, power-down, and
brownout conditions; an independent watchdog output
that goes low if the watchdog input has not been toggled
within 1.6s; a 0.62V threshold detector for power-fail
warning; and an active-low manual reset input.
The MAX6701–MAX6708 family offers several pinout
options to accommodate a variety of multivoltage micro-
processor supervision applications.
The MAX6701(A)/MAX6702(A)/MAX6703(A) monitor
three supply voltages (one fixed threshold and two
adjustable) to drive a single reset output and include a
manual reset input and a watchdog timer with an inde-
pendent output. The MAX6704 monitors a single-supply
voltage to drive complementary reset outputs and
includes an independent adjustable power-fail-in/power-
fail-out comparator, a manual reset input, and a reset-
based watchdog timer. The MAX6705(A)/MAX6706(A)/
MAX6707(A) monitor a single-supply voltage to drive a
single reset output and include an independent
adjustable power-fail-in/power-fail-out comparator, a
manual reset input, and a watchdog timer with an inde-
pendent output. The MAX6708 is the same as the
MAX6704 but without the watchdog timer function.
See the Detailed Description for differences between
non-A and A versions.
Features
o
Small 8-Pin SOT23 Package
o
Precision Monitoring of +5.0V, +3.3V, +3.0V, +2.5V
Supply Voltages
o
140ms Reset Timeout Delay
o
Power-Fail Input with Independent Output;
Monitor Inputs Down to 0.62V (MAX6704–MAX6708)
o
Dual Adjustable Reset Input for Triple-Voltage
Monitoring (MAX6701(A)/MAX6702(A)/MAX6703(A))
o
1.6s Watchdog Timeout Period
(MAX6701(A)–MAX6707(A))
o
Independent Watchdog Output
(MAX6701(A)/MAX6702(A)/MAX6703(A)/
MAX6705(A)/MAX6706(A)/MAX6707(A))
o
Manual Reset Input
o
Four Reset Output Stage Options
Active Low Push-Pull (MAX6701(A), MAX6705(A))
Active Low Open Drain (MAX6703(A), MAX6707(A))
Active High Push-Pull (MAX6702(A), MAX6706(A))
Dual Active Low/High Push-Pull (MAX6704,
MAX6708)
o
Guaranteed Reset Valid to V
CC
= 1V
o
Immune to Short Falling V
CC
Transients
o
Low Cost, Few External Components
MAX6701–08/MAX6701A–03A/05A–07A
Ordering Information
PART
MAX6701_KA-T
MAX6701A_KA-T
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
8 SOT23-8
8 SOT23-8
Applications
Computers
Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring
White Goods
Networking
Telecommunications
Insert the desired suffix letter (from the Threshold Suffix Guide
table) into the blank to complete the part number. All devices
must be ordered in increments of 2500 pieces. Sample stock is
typically held on standard versions only. Contact factory for
availability.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Ordering Information continued at end of data sheet.
Pin Configurations
TOP VIEW
MR
1
V
CC
2
GND
3
8
7
WDO
RESET (RESET)
WDI
RST_IN2
MAX6701(A)
MAX6702(A)
MAX6703(A)
6
5
RST_IN1
4
Typical Operating Circuit and Selector Guide appear at end
of data sheet.
( ) ARE FOR MAX6702(A) ONLY.
SOT23
Pin Configurations continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
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.
Low-Voltage, SOT23 µP Supervisors with Power-
Fail In/Out, Manual Reset, and Watchdog Timer
MAX6701–08/MAX6701A–03A/05A–07A
ABSOLUTE MAXIMUM RATINGS
V
CC
........................................................................-0.3V to +6.0V
Open-Drain
RESET, WDO, PFO
...........................-0.3V to +6.0V
Push-Pull RESET,
RESET, WDO, PFO
........-0.3V to (V
CC
+ 0.3V)
MR,
WDI, PFI, RST_IN1, RST_IN2 ..............-0.3V to (V
CC
+ 0.3V)
Input Current (V
CC
) .............................................................20mA
Output Current (RESET, RESET,
PFO, WDO)
.....................20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SOT23 (derate 8.9mW/°C above +70°C)............714mW
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
= +4.25V to +5.5V for L/M versions, V
CC
= +2.55V to +3.6V for the T/S/R versions, V
CC
= +2.1V to +2.75V for the Z/Y versions.
T
A
= -40°C to +125°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
Supply Current
MR
Unconnected
SYMBOL
V
CC
CONDITIONS
T
A
= 0°C to +125°C
T
A
= -40°C to +125°C
V
CC
< 5.5V, no load
I
CC
V
CC
< 3.6V, no load
V
CC
< 3.6V, no load (MAX6708 only)
MAX670_L/MAX670_AL
MAX670_M/MAX670_AM
MAX670_T/MAX670_AT
V
CC
Reset Threshold
(V
CC
falling)
V
TH
MAX670_S/MAX670_AS
MAX670_R/MAX670_AR
MAX670_Z/MAX670_AZ
MAX670_Y/MAX670_AY
Reset Threshold
Temperature Coefficient
V
CC
to Reset Output Delay
Reset Timeout Period
V
CC
Falling to
WDO
Delay
PFI, RST_IN1, RST_IN2
Threshold
PFI Hysteresis
t
RP
∆V
TH
V
CC
falling at 10mV/µs
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
MAX6701(A)/MAX6702(A)/MAX6703(A)/MAX6705(A)/
MAX6706(A)/MAX6707(A)
V
CC
= 1.8V to 5.5V
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
602
593
6
140
120
5
618
634
642
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
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
60
12
200
280
300
2.19
2.32
2.63
2.93
3.08
4.38
MIN
1.0
1.2
12
9
6
4.63
TYP
MAX
5.5
5.5
25
20
20
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
2.27
ppm/°C
µs
ms
µs
mV
mV
V
µA
UNITS
V
2
_______________________________________________________________________________________
Low-Voltage, SOT23 µP Supervisors with Power-
Fail In/Out, Manual Reset, and Watchdog Timer
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +4.25V to +5.5V for L/M versions, V
CC
= +2.55V to +3.6V for the T/S/R versions, V
CC
= +2.1V to +2.75V for the Z/Y versions.
T
A
= -40°C to +125°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
PFI, RST_IN1, RST_IN2
Leakage Current
PFI to
PFO
Delay
MR
Input Voltage
MR
Minimum Input Pulse
MR
Glitch Rejection
MR
to Reset Delay
V
CC
Rising to
WDO
Delay
MR
Pullup Resistance
Watchdog Timeout Period
WDI Pulse Width
WDI Input Voltage
WDI Input Current
t
WD
t
WDI
V
IL
V
IH
I
WDI
WDI = 0V or V
CC
V
CC
≥
1.0V, I
SINK
= 50µA, output asserted
(T
A
= 0°C to +125°C)
V
OL
V
CC
≥
1.2V, I
SINK
= 100µA, output asserted
V
CC
≥
2.55V, I
SINK
= 1.2mA, output asserted
V
CC
≥
4.25V, I
SINK
= 3.2mA, output asserted
PFO Output Low
(Push-Pull or Open Drain)
RESET, WDO, PFO
Output
High (Push-Pull Only)
RESET, WDO, PFO
Output
Open-Drain Leakage
Current
V
CC
≥
1.80V, I
SINK
= 200µA, output asserted
V
OL
V
CC
≥
2.55V, I
SINK
= 1.2mA, output asserted
V
CC
≥
4.25V, I
SINK
= 3.2mA, output asserted
V
OH
V
CC
≥
2.7V, I
SOURCE
= 500µA, output not asserted
V
CC
≥
4.75V, I
SOURCE
= 800µA, output not asserted
V
CC
> V
TH
, output not asserted
V
CC
≥
1.0V, I
SOURCE
= 1µA, reset asserted
(T
A
= 0°C to +125°C)
RESET Output High
(Push-Pull Only)
V
OH
V
CC
≥
1.2V, I
SOURCE
= 50µA, reset asserted
V
CC
≥
2.55V, I
SOURCE
= 500µA, reset asserted
V
CC
≥
4.25V, I
SOURCE
= 800µA, reset asserted
RESET Output Low
(Push-Pull Only)
V
OL
V
CC
≥
2.7V, I
SINK
= 1.2mA, reset not asserted
V
CC
≥
4.75V, I
SINK
= 3.2mA, reset not asserted
0.8 x V
CC
0.8 x V
CC
1.0
0.7 x V
CC
-1
+1
0.3
0.3
0.3
0.4
0.3
0.3
0.4
V
V
V
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
(Note 2)
t
MD
MAX6701(A)/MAX6702(A)/MAX6703(A)/
MAX6705(A)/MAX6706(A)/MAX6707(A)
25
1.12
0.96
50
0.3 x V
CC
t
PF
V
IL
V
IH
0.7 x V
CC
1
100
200
100
50
1.6
75
2.4
2.52
SYMBOL
(Note 2)
CONDITIONS
T
A
= -40°C to +85°C
T
A
= -40°C to +125°C
MIN
-50
-200
1
0.3 x V
CC
TYP
MAX
+50
+200
UNITS
nA
µs
V
µs
ns
ns
ns
kΩ
s
ns
V
µA
MAX6701–08/MAX6701A–03A/05A–07A
RESET, WDO
Output Low
(Push-Pull or Open Drain)
I
LKG
µA
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.3
0.4
V
V
Note 1:
Over-temperature limits are guaranteed by design and not production tested. Devices are tested at T
A
= +25°C.
Note 2:
Guaranteed by design. Not production tested.
_______________________________________________________________________________________
3
Low-Voltage, SOT23 µP Supervisors with Power-
Fail In/Out, Manual Reset, and Watchdog Timer
MAX6701–08/MAX6701A–03A/05A–07A
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
MAX6701 toc01
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6701 toc02
V
CC
TO RESET OUTPUT DELAY
vs. TEMPERATURE
MAX6701 toc03
20
210
20
V
CC
TO RESET OUTPUT DELAY (µs)
16
SUPPLY CURRENT (µA)
V
CC
= 5V
MAX6705(A)
RESET TIMEOUT PERIOD (ms)
205
15
12
200
10
8
V
CC
= 3.3V
MAX6708
4
195
5
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
190
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
WATCHDOG TIMEOUT PERIOD
vs. TEMPERATURE
MAX6701 toc04
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
MAX6701 toc05
MAXIMUM V
CC
TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAXIMUM TRANSIENT DURATION (µs)
MAX670_Y
50
40
30
20
10
0
RESET OCCURS
ABOVE LINE
MAX6701 toc06
1.70
WATCHDOG TIMEOUT PERIOD (s)
1.05
1.04
NORMALIZED RESET THRESOLD
1.03
1.02
1.01
1.00
0.99
0.98
0.97
0.96
60
1.65
1.60
1.55
1.50
-40
-15
10
35
60
85
TEMPERATURE (°C)
0.95
-40
-15
10
35
60
85
TEMPERATURE (°C)
0
40
80
120
160
RESET THRESHOLD OVERDRIVE (mV)
OUTPUT-VOLTAGE LOW
vs. SINK CURRENT
MAX6701 toc07
V
CC
- V
OH
vs. SOURCE CURRENT
V
CC
≥
4.25V
300
250
V
CC
- V
OH
(mV)
200
150
100
50
MAX6701 toc08
100
V
CC
≥
4.25V
75
V
OL
(mV)
350
50
25
0
0
400 800 1200 1600 2000 2400 2800 3200
SINK CURRENT (µA)
0
0
400 800 1200 1600 2000 2400 2800 3200
SOURCE CURRENT (µA)
4
_______________________________________________________________________________________
Low-Voltage, SOT23 µP Supervisors with Power-
Fail In/Out, Manual Reset, and Watchdog Timer
Pin Description
PIN
MAX6701(A)
MAX6702(A) MAX6704
MAX6703(A)
MAX6705(A)
MAX6706(A) MAX6708
MAX6707(A)
NAME
FUNCTION
MAX6701–08/MAX6701A–03A/05A–07A
1
1
1
1
MR
Active-Low, Manual Reset Input, Internal 50kΩ Pullup to V
CC
.
Pull low to force a reset. Reset remains active as long as
MR
is
low and the reset timeout period after
MR
goes high. Leave
unconnected or connect to V
CC
if unused.
WDO
deasserts
when
MR
is low (MAX6701(A)/MAX6702(A)/MAX6703(A)/
MAX6705(A)/ MAX6706(A)/MAX6707(A) only).
Supply Voltage for MAX6701–MAX6708 and Input for Primary
Reset Threshold Monitor. Push-pull outputs are powered by V
CC
.
Ground
Power-Fail Voltage Monitor Input. High-impedance input for
internal power-fail comparator. Connect this pin to an external
resistive-divider network to set the reset threshold voltage;
0.62V (typ) threshold. Connect to GND or V
CC
when not used.
Power-Fail Monitor Output. Open drain or push-pull active low.
PFO
goes low when PFI is less than 0.62V.
Watchdog Input. If WDI remains high or low for longer than the
watchdog timeout period, the internal watchdog timer runs out and
WDO
is asserted.
WDO
is asserted low after each watchdog
overflow and remains low until the watchdog timer is cleared (the
reset output is not affected). The internal watchdog timer clears
whenever a V
CC
/RST_IN1/RST_IN2 reset is asserted, the manual
reset is asserted, or WDI sees a rising or falling edge. The
watchdog timer remains cleared until the reset output is
deasserted. On the MAX6704,
RESET
pulse asserts for the reset
timeout period after each watchdog timeout overflow. The
watchdog timer cannot be disabled.
No Connection. Not internally connected.
Active-Low Reset Output (Open Drain or Push-Pull).
RESET
changes from high to low when the V
CC
input drops below the
selected reset threshold (or RST_IN1/ RST_IN2 for the
MAX6701(A)/MAX6702(A)/MAX6703(A),
MR
is pulled low, or the
watchdog triggers a reset (MAX6704 only).
RESET
remains low for
the reset timeout period after the reset conditions are terminated.
2
3
2
3
2
3
2
3
V
CC
GND
—
4
4
4
PFI
—
5
5
5
PFO
6
6
6
—
WDI
—
—
—
6
N.C.
7
7
7
7
RESET
_______________________________________________________________________________________
5
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