MAXIM MAX706P, MAX706R, MAX706S, MAX706T, MAX708R User Manual
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General Description
The MAX706P/R/S/T, MAX706AP/AR/AS/AT, and
MAX708R/S/T microprocessor (µP) supervisory circuits
reduce the complexity and number of components
required to monitor +3V power-supply levels in +3V to
+5V µP systems. These devices significantly improve
system reliability and accuracy compared to separate
ICs or discrete components.
The MAX706P/R/S/T and MAX706AP/AR/AS/AT supervisory circuits provide the following four functions:
1) A reset output during power-up, power-down, and
brownout conditions.
2) An independent watchdog output that goes low if the
watchdog input has not been toggled within 1.6s.
3) A 1.25V threshold detector for power-fail warning,
low-battery detection, or for monitoring a power
supply other than the main supply.
4) An active-low, manual-reset input.
The only difference between the MAX706R/AR,
MAX706S/AS, and MAX706T/AT is the reset-threshold
voltage levels, which are 2.63V, 2.93V, and 3.08V,
respectively. All have active-low reset output signals.
The MAX706P/AP are identical to the MAX706R/AR,
except the reset output signal is active-high. The watchdog timer function for the MAX706AP/AR/AS/AT disables when the WDI input is left open or connected to a
high-impedance state of a low-leakage tri-state output.
The MAX708R/S/T provide the same functions as the
MAX706R/S/T and MAX706AR/AS/AT except they do
not have a watchdog timer. Instead, they provide both
RESET and RESET outputs. As with the MAX706,
devices with R, S, and T suffixes have reset thresholds
of 2.63V, 2.93V, and 3.08V, respectively.
These devices are available in 8-pin SO, DIP, and
µMAX®packages and are fully specified over the operating temperature range.
Applications
Battery-Powered Equipment
Portable Instruments
Computers
Controllers
Intelligent Instruments
Critical µP Power Monitoring
Features
♦ µMAX Package, Small 8-Pin SO
♦ Precision Supply-Voltage Monitors
2.63V (MAX706P/R, MAX706AP/AR, and MAX708R)
2.93V (MAX706S, MAX706AS, and MAX708S)
3.08V (MAX706T, MAX706AT, and MAX708T)
♦ 200ms Reset Time Delay
♦ Debounced TTL/CMOS-Compatible Manual Reset
Input
♦ 100µA Quiescent Current
♦ WDI Disable Feature (MAX706AP/AR/AS/AT)
♦ Watchdog Timer: 1.6s Timeout
♦ Reset Output Signal:
Active-High Only (MAX706P, MAX706AP)
Active-Low Only (MAX706R/S/T, MAX706AR/AS/AT)
Active-High and Active-Low (MAX708R/S/T)
♦ Voltage Monitor for Power-Fail or Low-Battery
Warning
♦ 8-Pin Surface-Mount Package
♦ Guaranteed RESET Assertion to V
CC
= 1V
MAX706P/R/S/T, MAX706AP/AR/AS/AT, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-0099; Rev 5; 4/06
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.
Ordering Information continued at end of data sheet.
Pin Configurations appear at end of data sheet.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
PART†
TEMP
RANGE
PIN-
PKG
CODE
MAX706PCPA
0°C to +70°C 8 PDIP P8-1
MAX706PCSA
0°C to +70°C 8 SO S8-2
MAX706PCUA
0°C to +70°C 8 µMAX U8-1
MAX706PEPA
8 PDIP P8-1
†
SO, µMAX, and PDIP packages are available in lead-free.
V
CC
PFI
GND
MR
PFO
WDO
RESET
UNREGULATED
DC
PUSHBUTTON
SWITCH
WDI
I/O LINE
INTERRUPT
µP
MAX639
DC-DC
CONVERTER
+3V/+3.3V
MAX706R/S/T
MAX706AR/AS/AT
V
CC
RESET
NMI
Typical Operating Circuits
Typical Operating Circuits continued at end of data sheet.
PACKAGE
-40°C to +85°C
MAX706P/R/S/T, MAX706AP/AR/AS/AT, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(MAX70_P/R, MAX706AP/AR: VCC= 2.7V to 5.5V; MAX70_S, MAX706AS: V
CC
= 3.0V to 5.5V; MAX70_T, MAX706AT: V
CC
= 3.15V to
5.5V; T
J
= TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TJ= TA= +25°C.) (Note 2)
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)
V
CC
........................................................................-0.3V to +6V
All Other Inputs (Note 1)..........................-0.3V to (V
CC
+ 0.3V)
Input Current
V
CC
..................................................................................20mA
GND .................................................................................20mA
Output Current (all outputs) ................................................20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin CERDIP (derate 8mW/°C above +70°C)..............640mW
8-Pin PDIP (derate 9.1mW/°C above +70°C).............727.3mW
8-Pin SO (derate 5.9mW/°C above +70°C)................470.6mW
8-Pin µMAX (derate 4.5mW/
o
C above +70°C) ..............362mW
Operating Temperature Range
MAX70_C .............................................................0°C to +70°C
MAX70_E ..........................................................-40°C to +85°C
MAX70_M .......................................................-55°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: The input-voltage limits on PFI, WDI, and MR can be exceeded if the input current is less than 10mA.
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX70_C 1.0 5.5
Supply Voltage Range V
CC
MAX70_E/M 1.2 5.5
V
MAX706_C 90 200
MAX706_E/M 90 300
MAX708_C 50 200
VCC < 3.6V
MAX708_E/M 50 300
MAX706_C
350
MAX706_E/M
500
MAX708_C 65 350
Supply Current
VCC < 5.5V
MAX708_E/M 65 500
µA
MAX70_P/R/, MAX706AP/AR
MAX70_S, MAX706AS
Reset Threshold (Note 3)
(V
CC
Falling)
V
RST
MAX70_T, MAX706AT
V
Reset Threshold Hysteresis
(Note 3)
V
HYS
20 mV
MAX70_P/R/, MAX706AP/AR VCC = 3.0V
280
MAX70_S, MAX706AS, VCC = 3.3V
280Reset Pulse Width (Note 3) t
RST
VCC = 5V
ms
RESET OUTPUT
V
OH
)
0.8 x
V
OL
)
I
SINK
= 1.2mA 0.3
V
OH
4.5V < VCC < 5.5V
I
RSOURCE
=
800µA
VCC -
1.5
V
OL
4.5V < V
CC
< 5.5V I
SINK
= 3.2mA 0.4
MAX70_C VCC = 1.0V, I
SINK
= 50µA 0.3
Output-Voltage High
(MAX70_R/S/T)
(MAX706AR/AS/AT)
V
OL
MAX70_E/M: VCC = 1.2V, I
SINK
= 100µA 0.3
V
I
SUPPLY
V
RST(MAX
V
RST(MAX
< VCC < 3.6V I
< VCC < 3.6V
SOURCE
= 500µA
135
135
2.55 2.63 2.70
2.85 2.93 3.00
3.00 3.08 3.15
140 200
140 200
200
V
CC
MAX706P/R/S/T, MAX706AP/AR/AS/AT, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(MAX70_P/R, MAX706AP/AR: VCC= 2.7V to 5.5V; MAX70_S, MAX706AS: V
CC
= 3.0V to 5.5V; MAX70_T, MAX706AT: V
CC
= 3.15V to
5.5V; T
J
= TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TJ= TA= +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
OH
)
VCC -
0.6
V
OL
)
I
SINK
= 1.2mA 0.3
V
OH
4.5 < VCC < 5.5V
VCC -
1.5
Output-Voltage High
(MAX706P) (MAX706AP)
V
OL
4.5V < VCC < 5.5V I
SINK
= 3.2mA 0.4
V
V
OH
)
V
OL
)
I
SINK
= 500µA 0.3
V
OH
4.5V < VCC < 5.5V
VCC -
1.5
Output-Voltage High
(MAX708_)
V
OL
4.5V < VCC < 5.5V I
SINK
= 1.2mA 0.4
V
WATCHDOG INPUT
MAX706P/R, MAX706AP/AR, VCC = 3.0V
Watchdog Timeout Period t
WD
MAX706S/T, MAX706AS/AT, VCC = 3.3V
s
VIL = 0.4V
V
RST(MAX)
< V
CC
< 3.6V
WDI Pulse Width
(MAX706_, MAX706A_)
t
WP
VIH = 0.8V x V
CC
4.5V < VCC <
5.5V
50
ns
V
IL
V
RST(MAX)
< VCC < 3.6V 0.6
V
IH
V
RST(MAX)
< VCC < 3.6V
0.7 x
V
IL
V
CC
= 5.0V 0.8
Watchdog Input Threshold
(MAX706_, MAX706A_)
V
IH
V
CC
= 5.0V 3.5
V
MAX706_
WDI Input Current WDI = 0V or V
CC
MAX706A_ -5 +5
µA
V
RST(MAX
V
RST(MAX
V
RST(MAX
V
RST(MAX
< VCC < 3.6V I
< VCC < 3.6V
< VCC < 3.6V I
< VCC < 3.6V
= 215µA
SOURCE
I
I
SOURCE
SOURCE
SOURCE
= 800µA
= 500µA 0.8 x V
= 800µA
CC
1.00 1.60 2.25
1.00 1.60 2.25
100
V
CC
-1.0 +0.02 +1.0
MAX706P/R/S/T, MAX706AP/AR/AS/AT, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(MAX70_P/R, MAX706AP/AR: VCC= 2.7V to 5.5V; MAX70_S, MAX706AS: V
CC
= 3.0V to 5.5V; MAX70_T, MAX706AT: V
CC
= 3.15V to
5.5V; T
J
= TA= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at TJ= TA= +25°C.) (Note 2)
PARAMETER
CONDITIONS
UNITS
WATCHDOG OUTPUT
V
OH
)
0.8 x
V
OL
)
I
SINK
= 500µA 0.3
V
OH
4.5V < VCC < 5.5V
VCC -
1.5
WDO Output Voltage
(MAX706_, MAX706A_)
V
OL
4.5V < VCC < 5.5V I
SINK
= 1.2mA 0.4
V
MANUAL RESET INPUT
V
RST(MAX)
< V
CC
< 3.6V
25 70 250
MR Pullup Current MR = 0
4.5V < V
CC
<
5.5V
600
µA
V
RST(MAX)
< VCC < 3.6V
MR Pulse Width t
MR
4.5V < VCC < 5.5V
ns
V
IL
V
RST(MAX)
< VCC < 3.6V 0.6
V
IH
V
RST(MAX)
< VCC < 3.6V
0.7 x
V
IL
4.5V < VCC < 5.5V 0.8
MR Input Threshold
V
IH
4.5V < VCC < 5.5V 2.0
V
V
RST(MAX)
< VCC < 3.6V 750
MR to Reset Output Delay t
MD
4.5V < VCC < 5.5V 250
ns
POWER-FAILURE COMPARATOR
(MAX70_P/R, MAX706AP/AR) PFI falling
V
CC
= 3.0V
PFI Input Threshold
(MAX70_S/T, MAX706AS/AT) PFI falling,
V
CC
= 3.3V
V
PFI Input Current -25
nA
V
OH
)
0.8 x
V
OL
)
I
SINK
= 1.2mA 0.3
V
OH
4.5V < VCC < 5.5V
VCC -
1.5
PFO Output Voltage
V
OL
4.5V < VCC < 5.5V I
SINK
= 3.2mA 0.4
V
Note 2: All devices 100% production tested at TA= +85°C. Limits over temperature are guaranteed by design.
Note 3: Applies to both RESET in the MAX70_R/S/T and MAX706AR/AS/AT, and RESET in the MAX706P/MAX706AP.
SYMBOL
MIN TYP MAX
V
RST(MAX
V
RST(MAX
< VCC < 3.6V I
< VCC < 3.6V
SOURCE
I
SOURCE
= 500µA
= 800µA
V
RST(MAX
V
RST(MAX
< VCC < 3.6V I
< VCC < 3.6V
SOURCE
I
SOURCE
= 500µA
= 800µA
V
CC
100 250
500
150
V
CC
1.20 1.25 1.30
1.20 1.25 1.30
+0.01 +25
V
CC
MAX706P/R/S/T, MAX706AP/AR/AS/AT, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
_______________________________________________________________________________________ 5
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics
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