19-0536; Rev 3; 9/08
Dual/Triple, Ultra-Low-Voltage, SOT23 µP
Supervisory Circuits
General Description
The MAX6715A–MAX6729A/MAX6797A are ultra-low-volt-
age microprocessor (µP) supervisory circuits designed to
monitor two or three system power-supply voltages. These
devices assert a system reset if any monitored supply falls
below its factory-trimmed or adjustable threshold and main-
tain reset for a minimum timeout period after all supplies rise
above their thresholds. The integrated dual/triple supervisory
circuits significantly improve system reliability and reduce
size compared to separate ICs or discrete components.
These devices monitor primary supply voltages (V
CC
1)
from 1.8V to 5.0V and secondary supply voltages (V
CC
2)
from 0.9V to 3.3V with factory-trimmed reset threshold
voltage options (see the
Reset Voltage Threshold Suffix
Guide).
An externally adjustable RSTIN input option
allows customers to monitor a third supply voltage down
to 0.62V. These devices are guaranteed to be in the cor-
rect reset output logic state when either V
CC
1 or V
CC
2
remains greater than 0.8V.
A variety of push-pull or open-drain reset outputs along
with watchdog input, manual-reset input, and power-fail
input/output features are available (see the
Selector
Guide
). Select reset timeout periods from 1.1ms to
1120ms (min) (see the
Reset Timeout Period Suffix
Guide).
The MAX6715A–MAX6729A/MAX6797A are avail-
able in small 5-, 6-, and 8-pin SOT23 packages and oper-
ate over the -40°C to +125°C temperature range.
Features
o
V
CC
1 (Primary Supply) Reset Threshold Voltages
from 1.58V to 4.63V
o
V
CC
2 (Secondary Supply) Reset Threshold
Voltages from 0.79V to 3.08V
o
Externally Adjustable RSTIN Threshold for
Auxiliary/Triple-Voltage Monitoring
(0.62V Internal Reference)
o
Watchdog Timer Option
35s (min) Long Startup Period
1.12s (min) Normal Timeout Period
o
Manual-Reset Input Option
o
Power-Fail Input/Power-Fail Output Option
(Push-Pull and Open-Drain Active-Low)
o
Guaranteed Reset Valid Down to V
CC
1 or
V
CC
2 = 0.8V
o
Reset Output Logic Options
o
Immune to Short V
CC
Transients
o
Low Supply Current 14µA (typ) at 3.6V
o
Watchdog Disable Feature
o
Small 5-, 6-, and 8-Pin SOT23 Packages
MAX6715A–MAX6729A/MAX6797A
Ordering Information
PART
MAX6715AUT_
_D_+T
MAX6716AUT_
_D_+T
MAX6717AUK_
_D_+T
MAX6718AUK_
_D_+T
MAX6719AUT_
_D_+T
MAX6720AUT_
_D_+T
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-
PACKAGE
6 SOT23
6 SOT23
5 SOT23
5 SOT23
6 SOT23
6 SOT23
Applications
Multivoltage Systems
Telecom/Networking
Equipment
Computers/Servers
Portable/Battery-
Operated Equipment
Industrial Equipment
Printers/Fax Machines
Set-Top Boxes
Typical Operating Circuit
DC-DC OUT2
CONVERTER
OUT1
V
CC
1
V
CC
2
I/O
CORE
SUPPLY SUPPLY
RESET
I/O
NMI
µP
+Denotes
a lead-free/RoHS-compliant package.
T = Tape and reel.
UNREGULATED
DC
IN
1.8V
0.9V
R1
MAX6715A-
MAX6729A/
MAX6797A
RST
RSTIN/PFI
MR
WDI
PFO
MAX67_ _
Note:
The first “_ _” are placeholders for the threshold voltage
levels of the devices. Desired threshold levels are set by the part
number suffix found in the Reset Voltage Threshold Suffix Guide.
The “_” after the D is a placeholder for the reset timeout delay
time. Desired delay time is set using the timeout period suffix
found in the Reset Timeout Period Suffix Guide. For example, the
MAX6716AUTLTD3-T is a dual-voltage supervisor V
TH
1 =
4.625V, V
TH
2 = 3.075V, and 210ms (typ) timeout period.
Ordering Information continued at end of data sheet.
Pin Configurations and Selector Guide appear at end of
data sheet.
1
R2
PUSHBUTTON
SWITCH
________________________________________________________________
Maxim Integrated Products
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.
Dual/Triple, Ultra-Low-Voltage, SOT23 µP
Supervisory Circuits
MAX6715A–MAX6729A/MAX6797A
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
V
CC
1, V
CC
2 ..........................................................-0.3V to +6V
Open-Drain
RST, RST1, RST2, PFO,
RST ................-0.3V to +6V
Push-Pull RST,
RST1, PFO, RST...............-0.3V
to (V
CC
1 + 0.3V)
Push-Pull
RST2
.........................................-0.3V to (V
CC
2 + 0.3V)
RSTIN, PFI,
MR,
WDI ................................................-0.3V to +6V
Input Current/Output Current (all pins) ...............................20mA
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SOT23-5 (derate 7.1mW/°C above +70°C) ........571mW
6-Pin SOT23-6 (derate 8.7mW/°C above +70°C) ........696mW
8-Pin SOT23-8 (derate 8.9mW/°C above +70°C) ........714mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+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
1 = 0.8V to 5.5V, V
CC
2 = 0.8V to 5.5V, GND = 0V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 1)
PARAMETER
Supply Voltage
SYMBOL
V
CC
V
CC
1 < 5.5V all I/O connections open,
outputs not asserted
V
CC
1 < 3.6V all I/O connections open,
outputs not asserted
V
CC
2 < 3.6V all I/O connections open,
outputs not asserted
V
CC
2 < 2.75V all I/O connections open,
outputs not asserted
L (falling)
M (falling)
T (falling)
S (falling)
V
CC
1 Reset Threshold
V
TH1
R (falling)
Z (falling)
Y (falling)
W (falling)
V (falling)
T (falling)
S (falling)
R (falling)
Z (falling)
Y (falling)
W (falling)
V
CC
2 Reset Threshold
V
TH2
V (falling)
I (falling)
H (falling)
G (falling)
F (falling)
E (falling)
D (falling)
4.500
4.250
3.000
2.850
2.550
2.250
2.125
1.620
1.530
3.000
2.850
2.550
2.250
2.125
1.620
1.530
1.350
1.275
1.080
1.020
0.810
0.765
CONDITIONS
MIN
0.8
15
10
4
3
4.625
4.375
3.075
2.925
2.625
2.313
2.188
1.665
1.575
3.075
2.925
2.625
2.313
2.188
1.665
1.575
1.388
1.313
1.110
1.050
0.833
0.788
TYP
MAX
5.5
39
28
µA
11
9
4.750
4.500
3.150
3.000
2.700
2.375
2.250
1.710
1.620
3.150
3.000
2.700
2.375
2.250
1.710
1.620
1.425
1.350
1.140
1.080
0.855
0.810
V
V
UNITS
V
I
CC1
Supply Current
I
CC2
2
_______________________________________________________________________________________
Dual/Triple, Ultra-Low-Voltage, SOT23 µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
1 = 0.8V to 5.5V, V
CC
2 = 0.8V to 5.5V, GND = 0V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 1)
PARAMETER
Reset Threshold Tempco
Reset Threshold Hysteresis
V
CC
to Reset Output Delay
SYMBOL
∆V
TH
/°C
V
HYST
t
RD
Referenced to V
TH
typical
V
CC
1 = (V
TH
1 + 100mV) to (V
TH
1 - 100mV) or
V
CC
2 = (V
TH
2 + 75mV) to (V
TH
2 - 75mV)
D1
D2
D7 (MAX6797A only)
Reset Timeout Period
t
RP
D8 (MAX6797A only)
D3
D5
D6
D4
RSTIN Input Threshold
RSTIN Input Current
RSTIN Hysteresis
RSTIN to Reset Output Delay
PFI Input Threshold
PFI Input Current
PFI Hysteresis
PFI to
PFO
Delay
t
RSTIND
V
PFI
I
PFI
V
PFH
t
DPF
V
IL
V
IH
0.7
✕
V
CC
1
1
100
t
MR
25
First watchdog period after reset timeout
period
Normal mode
WDI Pulse Width
WDI Input Voltage
WDI Input Current
t
WDI
V
IL
V
IH
I
WDI
WDI = 0V or V
CC
1
0.7
✕
V
CC
1
-1
+1
(Note 2)
200
50
80
(V
PFI
+ 30mV) to (V
PFI
- 30mV)
V
RSTIN
to (V
RSTIN
- 30mV)
611
-100
3
2
0.3
✕
V
CC
1
V
RSTIN
I
RSTIN
1.1
8.8
17.5
35
140
280
560
1120
611
-100
3
22
626.5
642
+100
CONDITIONS
MIN
TYP
20
0.5
20
1.65
13.2
26.25
52.5
210
420
840
1680
626.5
2.2
17.6
35
70
280
560
1120
2240
642
+100
mV
nA
mV
µs
mV
nA
mV
µs
ms
MAX
UNITS
ppm/°C
%
µs
MAX6715A–MAX6729A/MAX6797A
ADJUSTABLE RESET COMPARATOR INPUT (MAX6719A/MAX6720A/MAX6723A–MAX6727A)
POWER-FAIL INPUT (MAX6728A/MAX6729A)
MANUAL-RESET INPUT (MAX6715A–MAX6722A/MAX6725A–MAX6729A)
MR
Input Voltage
MR
Minimum Pulse Width
MR
Glitch Rejection
MR
to Reset Delay
MR
Pullup Resistance
WATCHDOG INPUT (MAX6721A–MAX6729A)
Watchdog Timeout Period
t
WD
35
1.12
50
0.3
✕
V
CC
1
54
1.68
72
2.24
ns
V
µA
s
V
µs
ns
ns
kΩ
_______________________________________________________________________________________
3
Dual/Triple, Ultra-Low-Voltage, SOT23 µP
Supervisory Circuits
MAX6715A–MAX6729A/MAX6797A
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
1 = 0.8V to 5.5V, V
CC
2 = 0.8V to 5.5V, GND = 0V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 1)
PARAMETER
RESET/POWER-FAIL OUTPUTS
V
CC
1 or V
CC
2
≥
0.8V, I
SINK
= 1µA,
output asserted
V
CC
1 or V
CC
2
≥
1.0V, I
SINK
= 50µA,
output asserted
V
OL
V
CC
1 or V
CC
2
≥
1.2V, I
SINK
= 100µA,
output asserted
V
CC
1 or V
CC
2
≥
2.7V, I
SINK
= 1.2mA,
output asserted
V
CC
1 or V
CC
2
≥
4.5V, I
SINK
= 3.2mA,
output asserted
V
CC
1
≥
1.8V, I
SOURCE
= 200µA, output not
asserted
V
OH
V
CC
1
≥
2.7V, I
SOURCE
= 500µA, output not
asserted
V
CC
1
≥
4.5V, I
SOURCE
= 800µA, output not
asserted
V
CC
1
≥
1.8V, I
SOURCE
= 200µA, output not
asserted
V
OH
V
CC
1
≥
2.7V, I
SOURCE
= 500µA, output not
asserted
V
CC
1
≥
4.5V, I
SOURCE
= 800µA, output not
asserted
V
CC
1
≥
1.0V, I
SOURCE
= 1µA, reset asserted
RST
Output HIGH
(Push-Pull Only)
V
CC
1
≥
1.8V, I
SOURCE
= 150µA,
reset asserted
V
OH
V
CC
1
≥
2.7V, I
SOURCE
= 500µA,
reset asserted
V
CC
1
≥
4.5V, I
SOURCE
= 800µA,
reset asserted
V
CC
1 or V
CC
2
≥
1.8V, I
SINK
= 500µA,
reset not asserted
RST
Output LOW
(Push-Pull or Open Drain)
V
OL
V
CC
1 or V
CC
2
≥
2.7V, I
SINK
= 1.2mA,
reset not asserted
V
CC
1 or V
CC
2
≥
4.5V, I
SINK
= 3.2mA,
reset not asserted
Output not asserted
Output asserted
0.8
✕
V
CC
1
0.8
✕
V
CC
1
0.8
✕
V
CC
1
0.8
✕
V
CC
2
0.8
✕
V
CC
2
0.8
✕
V
CC
2
0.8
✕
V
CC
1
0.8
✕
V
CC
1
0.8
✕
V
CC
1
0.8
✕
V
CC
1
0.3
0.3
0.4
0.5
0.5
µA
µA
V
V
V
V
0.3
0.3
0.3
0.3
0.4
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RST/RST1/RST2/PFO
Output LOW
(Push-Pull or Open-Drain)
RST/RST1/PFO
Output HIGH
(Push-Pull Only)
RST2
Output HIGH
(Push-Pull Only)
RST/RST1/RST2/PFO
Output
Open-Drain Leakage Current
RST Output Open-Drain
Leakage Current
Note 1:
Devices tested at T
A
= +25°C. Overtemperature limits are guaranteed by design and not production tested.
Note 2:
Parameter guaranteed by design.
4
_______________________________________________________________________________________
Dual/Triple, Ultra-Low-Voltage, SOT23 µP
Supervisory Circuits
Typical Operating Characteristics
(V
CC
1 = 5V, V
CC
2 = 3.3V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(V
CC
1 = +5V, V
CC
2 = +3.3V)
MAX6715A-29A toc01
MAX6715A–MAX6729A/MAX6797A
SUPPLY CURRENT vs. TEMPERATURE
(V
CC
1 = +3.3V, V
CC
2 = +2.5V)
MAX6715A-29A toc02
SUPPLY CURRENT vs. TEMPERATURE
(V
CC
1 = +2.5V, V
CC
2 = +1.8V)
18
16
SUPPLY CURRENT (µA)
14
12
10
8
6
4
2
0
I
CC
2
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TOTAL
MAX6715A-29A toc03
20
18
16
SUPPLY CURRENT (µA)
14
12
10
8
6
4
2
0
I
CC
2
TOTAL
I
CC
1
20
18
16
SUPPLY CURRENT (µA)
14
12
10
8
6
4
2
0
I
CC
2
I
CC
1
TOTAL
20
I
CC
1
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
SUPPLY CURRENT vs. TEMPERATURE
(V
CC
1 = +1.8V, V
CC
2 = +1.2V)
MAX6715A-29A toc04
NORMALIZED/RESET WATCHDOG
TIMEOUT PERIOD vs. TEMPERATURE
MAX6715A-29A toc05
MAXIMUM V
CC
TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAXIMUM V
CC
TRANSIENT DURATION (µs)
RESET OCCURS ABOVE
THIS LINE
1000
MAX6715A-29A toc06
20
18
16
SUPPLY CURRENT (µA)
14
12
10
8
6
4
2
0
I
CC
2
I
CC
1
TOTAL
1.020
RESET/WATCHDOG TIMEOUT PERIOD
1.016
1.012
1.008
1.004
1.000
0.996
0.992
0.988
0.984
0.980
10,000
100
10
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
1
10
100
1000
RESET THRESHOLD OVERDRIVE (mV)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
NORMALIZED V
CC
RESET THRESHOLD
vs. TEMPERATURE
MAX6715A-29A toc07
RESET INPUT AND POWER-FAIL INPUT
THRESHOLD vs. TEMPERATURE
MAX6715A-29A toc08
V
CC
TO RESET DELAY
vs. TEMPERATURE
75mV OVERDRIVE
19
V
CC
TO RESET DELAY (µs)
18
17
16
15
14
13
12
11
10
MAX6715A-29A toc09
1.008
1.007
1.006
RESET THRESHOLD
1.005
1.004
1.003
1.002
1.001
1.000
0.999
0.998
638
637
636
RESET THRESHOLD
635
634
633
632
631
630
629
628
20
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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