MAX706/MAX706T/
MAX706S/MAX760R
Low-Power µP Supervisor Circuits
DESCRIPTION
The MAX706/MAX706T/MAX706S/MAX706R CMOS supervisor
circuits monitor power-supply and battery voltage level, and µP/µC
operation. Compared to pin-compatible devices offered by
Maxim Integrated Products, these devices feature 60 percent
DIP8
lower maximu m supply current.
The family offers several functional options. Each device
SOP8
generates a reset signal during power-up, power-down and
during brownout conditions.
MSOP8
A reset is generated when the supply drops below4.4V
(MAX706),3.08V (MAX706T),2.93V (MAX706S),2.63V(MAX706R).In
addition,the MAX706/T/S/R feature a 2.4 second watchdog timer. A versatile power-fail
circuit has a1.25V threshold, useful in ch ecking battery levels and non-5V supplies. All
devices have a manual reset ( MR ) input. The watchdog timer output will trigger a reset
if connected to MR .
All devices are available in DIP8, SOP8 and MSOP8 packages.
ORDER I NG
I NFORMATI ON
DEVICE
Package Type
MARKING
Packing
Packing Qty
MAX607N
DIP8L
MAX607
TUBE
2000pcs/box
MAX607TN
DIP8L
MAX607T
TUBE
2000pcs/box
MAX607SN
DIP8L
MAX607S
TUBE
2000pcs/box
MAX607RN
DIP8L
MAX607R
TUBE
2000pcs/box
MAX607M/TR
SOP8L
X607
REEL
2500pcs/reel
MAX607TM/TR
SOP8L
X607T
REEL
2500pcs/reel
MAX607SM/TR
SOP8L
X607S
REEL
2500pcs/reel
MAX607RM/TR
SOP8L
X607R
REEL
2500pcs/reel
MAX607MM/TR
MSOP8L
X607
REEL
3000pcs/reel
MAX607TMM/TR
MSOP8L
X607T
REEL
3000pcs/reel
MAX607SMM/TR
MSOP8L
X607S
REEL
3000pcs/reel
MAX607RMM/TR
MSOP8L
X607R
REEL
3000pcs/reel
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1
2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
FEATURES
Improved replacements for the Maximu m
MAX706/T/S/R
–
140µA maximum supply current
–
60% improvement
Precision power supply monitor
–
4.4V threshold (MAX706)
–
3.08V threshold (MAX706T)
–
2.93V threshold (MAX706S)
–
2.63V threshold(MAX706R)
Debounced manual reset input
Voltage monitor
–
1.25V threshold
–
Battery monitor/Auxiliary supply monitor
Watchdog timer (MAX706/ MAX706T/MAX706S/MAX706R)
300ms reset pulse width
MicroSO package
B L OCK DIAGRAM
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
APPLICATIONS
●
●
●
● Battery-operated systems
● Wireless communication systems
Computers and embedded controllers
Intelligent instruments
PDAs and handheld equipment
PIN CONFIGURATION
DIP/SOP
MSOP
PIN DESCRIPTION
Pin No.
MAX706/MAX706T/MAX706S/MAX706R
DIP/SOP
MSOP
Name
Pin Function
Manual RESET input. The active
LOW input triggers a reset
pulse. A 250µA pull-up current
allows the pin to be driven
by TTL / CMOS logic or shorted
to ground with a switch.
+5V power supply input.
1
3
MR
2
4
Vcc
3
5
GND
Ground reference for all signals.
Power-fail voltage monitor input.
4
6
PFI
5
7
PFO
6
8
WDI
With PFI less than 1.25V, PFO
goes low. Connect PFI to ground
or V C C when not used.
Power-fail output. The output is
active LOW and sinks current
when PFI is less than1.25V.
Watchdog input. WDI controls
the internal watchdog timer. A
HIGH or LOW signal for2.4sec at
WDI allows the internal timer to
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3
run-out, setting WDO LOW. The
watchdog function is disabled by
floating WDI or by connecting
WDI to a high-impedance
2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
6
7
8
WDI
1
RESET
three-state buffer. The internal
watchdog
timer clears when: RESET is
asserted; WDI is three-stated; or
WDI sees a rising or falling edge.
Active-LOW reset output. Pulses
LOW for 300ms when triggered,
and stays low whenever Vcc is
below the reset threshold (MAX706:
4.4V, MAX706T: 3.08V, MAX706S:
1.93V,MAX706R:2.63). RESET
remains LOW for 300ms after
Vcc rises above the RESET
threshold or MR goes from
LOW to HIGH. A watchdog
timeout will not trigger RESET
unless WDO is connected to
MR .
8
Watchdog output. WDO pulls
LOW when the 2.4 sec internal
watchdog timer times-out and
does not go HIGH until the
watchdog is cleared. In addition,
when Vcc is below the reset
2
WDO
threshold, WDO remains low.
Unlike RESET , WDO does not
have a minimum pulse width and
as soon as Vcc exceeds the reset
threshold, WDO goes HIGH with
no delay.
ABSOLUTE MAXIMUM RATING (Ta=25 ℃ )
Characteristics
Supply voltage
All other inputs *1
Input current at Vcc and GND
Output current :All outputs
Rate of Rise at Vcc
Plastic DIP power dissipation (Derate 9mW/℃ above 70 ℃ )
SOP power dissipation (Derate 5.9mW/℃ above 70 ℃ )
MSOP power dissipation (Derate 4.1mW/℃ above 70 ℃ )
Operating temp erature range
Storage temperature range
Lead temperature (soldering,10 sec.)
Value
-0.3～ +6.0
-0.3～ Vcc+0.3
20
20
100
700
470
330
0～ 70
-65 ～ +150
300
Unit
V
V
mA
mA
V/µs
mW
mW
mW
℃
℃
℃
* 1 . T h e i n p u t v o l t a g e l i m i t s o n P F I a n d MR c a n b e e x c e e d e d i f t h e i n p u t c u r r e n t i s l e s s t h a n
10mA.
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
ELECTRICAL CHARACTERISTICS
（ Unless otherwise noted, V C C = 4.5V to 5.5V for the MAX706/MAX706T/MAX706S/MAX706R）
Characteristics
Symbol
Conditions
Min.
Typ .
Max Unit
Operating voltage range
Vcc
MAX706/T/S/R
1.2
5.5
V
Supply current
Icc
MAX706/T/S/R
75
140
µA
MAX 706
4.25
4.4
4.5
MAX 706T
2.98
3.08 3.15
V
V RT
RESET threshold
MAX 706S
2.83
2.93
3
MAX 706R
2.54
2.63 2.69
40
mV
RESET threshold hysteresis
RESET pulse width
MR pulse width
MR to
o ut
RESET
delay
MR input threshold
t RS
1 40
t MR
0.15
0.25
WDI input threshold
WDI input current
WDO output voltage
PFI input threshold
PFI input current
PFO output voltage
t WD
t WP
V IH
V IL
ms
µs
2.0
V IH
V IL
RESET output voltage
420
µs
t MD
MR =0V
100
I S O U R C E =800µA
I S I N K =3.2mA
MAX706/T/S/R,Vcc=1.2
V, I S I N K =100µA
MAX 706/T/S/R
V IL =0.4V,V IH =0.8Vcc
Vcc-1.5
MR pull-up current
Watchdog timeout period
WDI pulse width
300
MAX706/T/S/R,Vcc=5V
250
V
0.8
600
µA
0.4
V
0.3
2.00
50
3.5
MAX706/T/S/R,WDI=Vcc
MAX706/T/S/R,WDI=0V -150
MAX706/T/S/R,
Vcc-1.5
I S O U R C E =800µA
MAX706/T/S/R,
I S I N K =1.2mA
Vcc=5V
1.20
-25
Vcc-1.5
I S O U R C E =800µA
I S I N K =3.2mA
2.4
50
-50
3.00
0.8
150
s
ns
V
µA
V
0.4
1.25
0.01
1.30
25
V
nA
0.4
V
FEATURE SUMMARY
Power-fail detector
Brownout detection
Manual RESET input
Power-up/down RESET
Watchdog timer
Active-HIGH RESET output
Active-LOW RESET output
RESET threshold
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MAX706
●
●
●
●
●
MAX706T
●
●
●
●
●
MAX706S
●
●
●
●
●
MAX706R
●
●
●
●
●
●
4.4V
●
3.08V
●
2.93V
●
2.63V
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
DETAIL DESCRIPTIONS
RESET Operation
The RESET signals are designed to start a µP/µC in a known state or return the system
to a known state.
RESET is guaranteed to be LOW with Vcc above 1.2V. During a power-up sequence,
RESET remains low until the supply rises above the threshold level, either 4.4V, 3.08V,
2.93V or 2.63V. RESET goes high approximately 300ms after crossing the threshold.
During power-down, RESET goes LOW as Vcc falls below the threshold level and is
guaranteed to be under 0.4V with Vcc above 1.2V.
In a brownout situation where Vcc falls below the threshold level, RESET pulses low.
If a brownout occurs during an already initiated reset, the pulse will continue for a
minimum of 140ms.
Auxiliary Comparator
All devices have an auxiliary comparator with 1.25V trip point and uncommitted output
( PFO ) and noninverting input (PFI). This comp arator can be used as a supply voltage
monitor with an external resistor voltage divider. The attenuated voltage at PFI should
be set just below the 1.25 threshold. As the supply level falls, PFI is reduced causing the
PFO output to transit LOW. Normally PFO interrupts the processor so the system can
be shut down in a controlled manner.
Manual Reset ( MR )
The active-LOW manual reset input is pulled high by a 250µA pull-up current and can be
driven low by CMOS/TTL logic or a mechan ical switch to ground. An external debounce
circuit is unnecessary since the 140ms minimu m reset time will debounce mechanical
pushbutton switches.
By connecting the watchdog output ( WDO ) and MR , a watchdog timeout forces RESET
to be generated.
Watchdog Timer
The watchdog timer available on the MAX 706/MAX706T/MAX706S/MAX706R monitors µP/µC
activity. If activity is not detected within 2.4 seconds, the internal timer puts the
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
watchdog output, WDO ,into a LOW state. WDO will remain LOW until activity is
detected at WDI.
The watchdog function is disabled, meaning it is cleared and not counting, if WDI is
floated or connected to a three-stated circuit. The watchdog timer is also disabled if
RESET is asserted. When RESET becomes inactive and the WDI input sees a high or low
transition as short as 50ns, the watchdog timer will begin a 2.4 second countdown.
Additional transitions at WDI will reset the watchdog timer and initiate a new
countdown sequence.
WDO will also become LOW and remain so, whenever the supply voltage, Vcc , falls
below the device threshold level. WDO goes HIGH as soon as Vcc transitions above the
threshold. There is no minimum pulse width for WDO as there is for the RESET
outputs. If WDI is floated, WDO essentially acts as a low-power output indicator.
APPLICATION INFORMATION
Ensuring That RESET is Valid Down to Vcc = 0V
When Vcc falls below 1.1V, the MAX706/MAX706T/MAX706S/MAX706R RESET output no longer
pulls down; it becomes indeterminate. To avoid the possibility that stray charges build
up and force RESET to the wrong state, a pull-down resistor should be connected to the
RESET pin,thus draining such charges to ground and holding RESET low. The resistor
value is not critical. A 100k Ω resistor will pull RESET to ground without loading it.
Bi-directional Reset Pin Interfacing
The MAX706/MAX706T/MAX706S/MAX706R can interface with µP/µC bi-directional reset pins by
connecting a 4.7kΩ resistor in series with the RESET output and the µP/µC
bi-directional RESET pin.
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
MAX706x
MAX706x
Monitoring Voltages Other Than Vcc
The MAX706/MAX706T/MAX706S/MAX706R can monitor voltages other than Vcc using the Power
Fail circuitry. If a resistive divider is connected from the voltage to be monitored to the
Power Fail input, PFI, the PFO (output) will go LOW if the divider voltage goes below
its 1.25V reference. Should hysteresis be desired, connect a resistor (equal to
approximately 10 times the sum of the two resistors in the divider) between the PFI and
PFO pins. A capacitor between PFI and GND will reduce circuit sensitivity to input
high-frequency noise. If it is desired to assert a RESET in addition to the PFO flag,
this may be achieved by connecting the PFO output to MR .
Monitoring a Negative Voltage
The Power-Fail circuitry can also monitor a negative supply rail. When the negative rail
is OK, PFO will be LOW, and when the negative rail is failing (not negative enough),
PFO goes HIGH(the opposite of when positive voltages are monitored). To trigger a
reset, these outputs need to be inverted: adding the resistors and transistor as shown
achieves this. The RESET output will then have the sa me sense as for positive voltages:
good = HIGH, bad = LOW. It should be noted that this circuit’s accuracy depends on the
Vcc line, the PFI threshold tolerance, and the resistors.
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
MAX706x
MAX706x
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
PACKAGE
SOP8
Dimensions In Millimeters
Symbol
Min
Max
Symbol
Min
Max
A
1.225
1.570
D
A1
Q
B
a
C
b
C1
DIP8
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
PACKAGE
A
A2
MSOP8
D
E
E1
A1
e
b
©
L
0.25
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2022 JAN
MAX706/MAX706T/
MAX706S/MAX760R
Important statement:
Huaguan Semiconductor Co,Ltd. reserves the right to change
the products and services provided without notice. Customers
should obtain the latest relevant information before ordering,
and verify the timeliness and accuracy of this information.
Customers are responsible for complying with safety
standards and taking safety measures when using our
products for system design and machine manufacturing to
avoid potential risks that may result in personal injury or
property damage.
Our products are not licensed for applications in life support,
military, aerospace, etc., so we do not bear the consequences
of the application of these products in these fields.
Our documentation is only permitted to be copied without
any tampering with the content, so we do not accept any
responsibility or liability for the altered documents.
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