_______________General Description
The MAX814/MAX815/MAX816 are high-accuracy
microprocessor (P) supervisory circuits that provide
power-on reset, watchdog, and power-fail functions.
They eliminate manual trimming and improve reliability
in critical applications needing high-accuracy reset
thresholds. The RESET output is guaranteed to be in
the correct state for V
CC
down to 1V. The reset com-
parator is designed to ignore fast transients on V
CC
.
Reset thresholds are available for operation with a vari-
ety of 3V and 5V supply voltages.
A 75A maximum supply current makes the MAX814/
MAX815/MAX816 ideal for use in portable equipment.
All three devices are available in 8-pin DIP and SO
packages. See the
Selector Table below for a review of
features.
________________________Applications
Medical Equipment
Controllers
Intelligent Instruments
Critical P Power Monitoring
Portable/Battery-Powered Equipment
Set-Top Boxes
____________________________Features
o
1% Worst-Case Reset Threshold Accuracy
o
4.8V, 4.7V, 4.55V, 3.03V, or Adjustable Reset
Thresholds
o
1% Low-Line Threshold Accuracy (MAX814)
60mV Above Reset Threshold
o
200ms Reset Time Delay
o
Active-Low RESET Output
Active-High RESET Output (MAX814/MAX816)
o
75A Max Supply Current
o
Guaranteed RESET Valid to V
CC
= 1V
o
Manual Reset Input
o
2% Power-Fail Comparator
o
Independent Watchdog with 1.56sec Timeout
(MAX815)
o
Power-Supply Glitch Immunity
o
8-Pin SO and DIP Packages
MAX814/MAX815/MAX816
1% Accuracy, Low-Power, +3V and +5V
P Supervisory Circuits
________________________________________________________________
Maxim Integrated Products
1
LOW LINE
GND
PFO
PFI
1
2
8
7
RESET
RESET
V
CC
MR
MAX814
DIP/SO
TOP VIEW
3
4
6
5
WDI
GND
PFO
PFI
1
2
8
7
WDO
RESET
V
CC
MR
MAX815
DIP/SO
3
4
6
5
RESET IN
GND
PFO
PFI
1
2
8
7
RESET
RESET
V
CC
MR
MAX816
DIP/SO
3
4
6
5
__________________________________________________________Pin Configurations
Call toll free 1-800-998-8800 for free samples or literature.
19-0412; Rev 0; 6/95
_____________________Selector Table
_____________Reset Trip Thresholds
Ordering Information appears at end of data sheet.
FEATURE
MAX814
MAX815
MAX816
RESET Output
RESET Output
Manual Reset
V
CC
Reset Voltage
K, L, N, T
K, L, N, T
Adjustable
Power-Fail Monitor
Low-Line Detector
Watchdog Circuit
MAX814/MAX815
K
4.75
4.85
L
4.65
4.75
N
4.50
4.60
T
3.00
3.06
MAX816
SUFFIX
RESET TRIP THRESHOLD
MIN (V)
MAX (V)
--
Adjustable
MAX814/MAX815/MAX816
1% Accuracy, Low-Power, +3V and +5V
P Supervisory Circuits
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS, +5V Parts (MAX814/MAX815K, L, N)
(V
CC
= 4.85V to 5.5V for MAX814K/MAX815K, V
CC
= 4.75V to 5.5V for MAX814L/MAX815L, V
CC
= 4.60V to 5.5V for MAX814N/
MAX815N, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
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 GND)
V
CC
....................................................................-0.3V to +6.0V
All Other Pins (Note 1)........................... -0.3V to (V
CC
+ 0.3V)
Terminal Current (PFI, RESET IN, MR)................................10mA
Terminal Current (all other pins) .........................................20mA
Continuous Power Dissipation (T
A
= +25C)
Plastic DIP (derate 9.09mW/C above +70C) ............727mW
SO (derate 5.88mW/C above +70C) .........................471mW
Operating Temperature Ranges
Commercial.........................................................0C to +70C
Extended ...........................................................-40C to +85C
Storage Temperature Range .............................-65C to +125C
MAX814K, V
CC
rising
MAX814_E, V
CC
falling
MAX814_C, V
CC
falling
MAX814_C, MAX815_C
MAX815 (Note 1)
WDI = V
CC
or WDI = 0V
MAX814_E, MAX815_E
MAX815, V
CC
= 5.0V
MAX814_C, MAX815_C
MAX815
MAX815
MAX814
MAX814_E/MAX815_E, V
CC
= 1.2V, I
SINK
= 100A
MAX814_C/MAX815_C, V
CC
= 1.0V, I
SINK
= 50A
MAX814_E, MAX815_E
MAX814K, MAX815K
MAX814L, MAX815L
I
SINK
= 3.2mA
MAX814N, MAX815N
I
SOURCE
= 800A
CONDITIONS
4.93
mV
48
73
V
LL
LOW LINE to RESET Differential
Threshold
50
70
s
1
t
WDO
MR to WDO High Delay
A
-1.0
1.0
I
WDI
WDI Input Current
V
2.4
V
WDI
WDI Input Threshold
0.8
ns
50
t
WP
WDI Pulse Width
sec
1.12
2.00
t
WD
Watchdog Timeout Period
V
0.3
RESET, WDO, PFO, LOW LINE
Output Voltage
0.3
0.4
V
OL
V
CC
-1.5
V
OH
75
V
1.2
5.5
V
CC
1.0
5.5
Operating Voltage Range
V
0.4
V
OL
RESET Output Voltage
V
CC
-1.5
V
OH
ms
140
200
250
t
RS
Reset Pulse Width
mV
0
V
RT
Reset Threshold Hysteresis
A
85
I
SUPPLY
Supply Current
4.75
4.85
4.65
4.75
V
4.50
4.60
V
RT
Reset Threshold
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MAX814L, V
CC
rising
4.83
V
LLT
MAX814N, V
CC
rising
4.68
V
LOW LINE Threshold
I
SOURCE
= 800A
I
SINK
= 3.2mA
Low
High
MAX814/MAX815/MAX816
1% Accuracy, Low-Power, +3V and +5V
P Supervisory Circuits
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS, +5V Parts (MAX814/MAX815K, L, N) (continued)
(V
CC
= 4.85V to 5.5V for MAX814K/MAX815K, V
CC
= 4.75V to 5.5V for MAX814L/MAX815L, V
CC
= 4.60V to 5.5V for MAX814N/
MAX815N, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS, +3V Parts (MAX814/MAX815T, MAX816)
(V
CC
= 3.06V to 5.5V for MAX814T/MAX815T and MAX816, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
0C to +70C
-40C to +85C
0C to +70C
MAX815T
T
A
= -40C to +85C, V
CC
= 1.2V, I
SINK
= 100A
T
A
= 0C to +70C, V
CC
= 1.0V, I
SINK
= 50A
MAX816
-40C to +85C
0C to +70C
-40C to +85C
V
RT
(max)<V
CC
<3.6V
CONDITIONS
I
SOURCE
= 500A
sec
1.12
2.00
t
WD
Watchdog Timeout Period
0.3
I
SINK
= 1.2mA
0.3
0.3
V
OL
0.8 x V
CC
V
OH
75
V
1.2
5.5
V
CC
1.0
5.5
Operating Voltage Range
0.3
V
OL
0.8 x V
CC
V
OH
ms
140
200
250
t
RS
Reset Pulse Width
nA
-15
6
35
I
RT
RESET IN Input Current
A
85
I
SUPPLY
Supply Current
3.00
3.06
3.00
3.08
V
V
RT
Reset Threshold
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MAX816C
MAX816E
1.683
1.700
1.717
1.678
1.700
1.722
V
V
RT
RESET IN Threshold
mV
0
V
RT
Reset Threshold Hysteresis
I
SOURCE
= 800A
I
SINK
= 3.2mA
V
0.4
V
OL
RESET Output Voltage
V
CC
-1.5
V
OH
V
RT
(max)<V
CC
<3.6V;
MAX814T, MAX816
4.5V<V
CC
<5.5V;
MAX814T, MAX816
I
SOURCE
= 500A
I
SINK
= 1.2mA
V
OL
RESET, WDO, PFO, LOW LINE
Output Voltage
V
4.5V<V
CC
<5.5V
0.4
V
CC
-1.5
V
OH
I
SOURCE
= 800A
I
SINK
= 3.2mA
V
OL
CONDITIONS
MR Input Threshold
V
MRHI
High
0.7 x V
CC
V
MR to RESET Out Delay
t
MD
(Note 3)
250
ns
PFI Input Threshold
V
PFI
V
CC
= 5.0V
2.45
2.50
2.55
V
PFI Input Current
I
PFI
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
MR Pull-Up Current
I
MR
MR = 0V
70
240
A
MR Pulse Width
t
MR
150
ns
V
MRLO
Low
1.1
-15.00
6.0
35.00
nA
LOW LINE, PFO, WDO
Assertion Delay
(Note 2)
200
s
MAX814/MAX815/MAX816
1% Accuracy, Low-Power, +3V and +5V
P Supervisory Circuits
4
_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS, +3V Parts (MAX814/MAX815T, MAX816) (continued)
(V
CC
= 3.06V to 5.5V for MAX814T/MAX815T and MAX816, T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
V
CC
rising
V
CC
falling, MAX814TE
V
CC
falling, MAX814TC
MAX815T (Note 1)
WDI = V
CC
or 0V, MAX815T
V
RT
(max)<V
CC
<3.6V;
MAX815T
MAX815T
Low
CONDITIONS
3.163
MR Input Threshold
mV
48
73
V
LL
LOW LINE to RESET Differential
Threshold
50
70
V
MRHI
High
s
1
t
WDO
MR to WDO High Delay
A
-1.0
1.0
I
WDI
WDI Input Current
V
0.7 x V
CC
0.8
0.7 x V
CC
V
100
t
WP
WDI Pulse Width
High
MR to RESET Out Delay
t
MD
V
RT
(max)<V
CC
<3.6V; (Note 3)
750
PFI Input Threshold
V
PFI
V
CC
= 3.3V, 5V
1.666
1.700
1.734
V
PFI Input Current
I
PFI
UNITS
MIN
TYP
MAX
SYMBOL
PARAMETER
V
LLT
V
MR Pull-Up Current
I
MR
MR = 0V
70
240
A
MR Pulse Width
t
MR
V
RT
(max)<V
CC
<3.6V
500
ns
V
MRLO
Low
1.1
-15.00
6.0
35.00
nA
LOW LINE Threshold
50
4.5V<V
CC
<5.5V
V
RT
(max)<V
CC
<3.6V
V
CC
= 5.0V; MAX815T
Low
2.4
V
WDI
WDI Input Threshold
0.8
High
110
370
4.5V<V
CC
<5.5V
150
4.5V<V
CC
<5.5V, (Note 3)
250
ns
V
RT
(max)<V
CC
<3.6V
4.5V<V
CC
<5.5V
Note 1:
Applies if WDO is externally connected to MR or if MR is externally driven.
Note 2:
On power-up, delay from reset trip threshold crossing to valid outputs.
Note 3:
Applies to both RESET and RESET.
ns
MAX814/MAX815/MAX816
1% Accuracy, Low-Power, +3V and +5V
P Supervisory Circuits
_______________________________________________________________________________________
5
70
30
-60 -40 -20
40
100
V
CC
SUPPLY CURRENT vs. TEMPERATURE
3V PARTS (MAX814T/MAX815T, MAX816)
45
40
35
65
MAX814-01
TEMPERATURE (C)
V
CC
SUPPLY CURRENT (
A)
0
20
60
80
60
55
50
V
CC
= 5.0V
V
CC
= 3.3V
V
CC
= 2.5V
70
30
-60 -40 -20
40
100
V
CC
SUPPLY CURRENT vs. TEMPERATURE
5V PARTS (MAX814/MAX815K, L, N)
45
40
35
65
MAX814-02
TEMPERATURE (C)
V
CC
SUPPLY CURRENT (
A)
0
20
60
80
60
55
50
V
CC
= 5.0V
V
CC
= 3.3V
200
175
-60 -40 -20
40
100
RESET TIMEOUT PERIOD
vs. TEMPERATURE
185
180
MAX814-03
TEMPERATURE (C)
RESET TIMEOUT PERIOD (ms)
0
20
60
80
195
190
V
CC
= 5.0V
V
CC
= 3.3V
40
15
-60 -40 -20
40
100
RESET-COMPARATOR PROPAGATION
DELAY vs. TEMPERATURE
25
20
MAX814-04
TEMPERATURE (C)
PROPAGATION DELAY (
s)
0
20
60
80
35
30
100mV OVERDRIVE
(V
RT
- V
CC
)
1.715
1.670
-60 -40 -20
40
100
PFI THRESHOLD vs. TEMPERATURE
3V PARTS (MAX814T/MAX815T, MAX816)
1.685
1.680
1.675
1.710
MAX814-05
TEMPERATURE (C)
PFI THRESHOLD (V)
0
20
60
80
1.705
1.700
1.695
1.690
2.550
2.450
-60 -40 -20
40
100
PFI THRESHOLD vs. TEMPERATURE
5V PARTS (MAX814/MAX815K, L, N)
2.490
2.470
2.480
2.460
2.540
MAX814-06
TEMPERATURE (C)
PFI THRESHOLD (V)
0
20
60
80
2.530
2.520
2.500
2.510
__________________________________________Typical Operating Characteristics
(T
A
= +25C, unless otherwise noted.)
60
0
-60 -40 -20
40
100
LOW-LINE COMPARATOR
PROPAGATION DELAY vs. TEMPERATURE
30
20
10
MAX814-11
TEMPERATURE (C)
PROPAGATION DELAY (
s)
0
20
60
80
50
40
100mV OVERDRIVE
(V
LLT
- V
CC
)
70
50
-60 -40 -20
40
100
LOW-LINE TO RESET THRESHOLD vs.
TEMPERATURE (V
CC
RISING)
58
54
56
52
68
MAX814-10
TEMPERATURE (C)
LOW-LINE TO RESET THRESHOLD (mV)
0
20
60
80
66
64
60
62
70
50
-60 -40 -20
40
100
LOW-LINE TO RESET THRESHOLD vs.
TEMPERATURE (V
CC
FALLING)
58
54
56
52
68
MAX814-09
TEMPERATURE (C)
LOW-LINE TO RESET THRESHOLD (mV)
0
20
60
80
66
64
60
62
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