19-0412; Rev 1; 12/05
±1% Accuracy, Low-Power, +3V and +5V
µP Supervisory Circuits
_______________General Description
The MAX814/MAX815/MAX816 are high-accuracy
microprocessor (µP) 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 75µA 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 pack-
ages. See the
Selector Table
for a review of features.
____________________________Features
♦
±1% Worst-Case Reset Threshold Accuracy
♦
4.8V, 4.7V, 4.55V, 3.03V, or Adjustable Reset
Thresholds
♦
±1% Low-Line Threshold Accuracy (MAX814)
60mV Above Reset Threshold
♦
200ms Reset Time Delay
♦
Active-Low RESET Output
Active-High RESET Output (MAX814/MAX816)
♦
75µA Max Supply Current
♦
Guaranteed RESET Valid to V
CC
= 1V
♦
Manual Reset Input
♦
±2% Power-Fail Comparator
♦
Independent Watchdog with 1.56sec Timeout
(MAX815)
♦
Power-Supply Glitch Immunity
♦
8-Pin SO and DIP Packages
MAX814/MAX815/MAX816
_____________________Selector Table
FEATURE
RESET Output
RESET Output
Manual Reset
V
CC
Reset Voltage
Power-Fail Monitor
Low-Line Detector
Watchdog Circuit
MAX814
✔
✔
✔
K, L, N, T
✔
✔
✔
✔
K, L, N, T
✔
MAX815
✔
MAX816
✔
✔
✔
Adjustable
✔
______________Ordering Information
PART*
MAX814_CPA
TEMP RANGE
0°C to +70°C
PIN-PACKAGE
8 PDIP
________________________Applications
Medical Equipment
Controllers
Intelligent Instruments
Critical µP Power Monitoring
Portable/Battery-Powered Equipment
Set-Top Boxes
*The
MAX814/MAX815 offer a choice of reset threshold voltages.
From the Reset Trip Threshold table, select the suffix corre-
sponding to the desired threshold and insert it into the blank to
complete the part number.
Devices are available in both leaded and lead-free packaging.
Specify lead free by adding the + symbol at the end of the part
number when ordering.
Ordering Information continued at end of data sheet.
Reset Trip Thresholds table appears at end of data sheet.
__________________________________________________________Pin Configurations
TOP VIEW
MR
1
V
CC
2
GND
3
PFI
4
8
RESET
RESET
LOW LINE
PFO
MR
1
V
CC
2
GND
3
PFI
4
8
WDO
RESET
WDI
PFO
MR
1
V
CC
2
GND
3
PFI
4
8
RESET
RESET
RESET IN
PFO
MAX814
7
6
5
MAX815
7
6
5
MAX816
7
6
5
DIP/SO
DIP/SO
DIP/SO
________________________________________________________________
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.
±1% Accuracy, Low-Power, +3V and +5V
µP Supervisory Circuits
MAX814/MAX815/MAX816
ABSOLUTE MAXIMUM RATINGS
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
= +25°C)
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
SO (derate 5.88mW/°C above +70°C) .........................471mW
Operating Temperature Ranges
Commercial.........................................................0°C to +70°C
Extended ...........................................................-40°C to +85C
Storage Temperature Range .............................-65°C to +125°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, +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.)
PARAMETER
Operating Voltage Range
Supply Current
SYMBOL
V
CC
I
SUPPLY
CONDITIONS
MAX814_C, MAX815_C
MAX814_E, MAX815_E
MAX814_C, MAX815_C
MAX814_E, MAX815_E
MAX814K, MAX815K
Reset Threshold
Reset Threshold Hysteresis
Reset Pulse Width
RESET Output Voltage
t
RS
V
OH
V
OL
V
OH
RESET, WDO, PFO, LOW LINE
Output Voltage
Watchdog Timeout Period
WDI Pulse Width
WDI Input Threshold
WDI Input Current
MR to WDO High Delay
LOW LINE to RESET Differential
Threshold
LOW LINE Threshold
V
OL
t
WD
t
WP
V
WDI
I
WDI
t
WDO
∆V
LL
MAX814
I
SOURCE
= 800µA
I
SINK
= 3.2mA
MAX814_C/MAX815_C, V
CC
= 1.0V, I
SINK
= 50µA
MAX814_E/MAX815_E, V
CC
= 1.2V, I
SINK
= 100µA
MAX815
MAX815
MAX815, V
CC
= 5.0V
WDI = V
CC
or WDI = 0V
MAX815 (Note 1)
MAX814_C, V
CC
falling
MAX814_E, V
CC
falling
MAX814K, V
CC
rising
V
LLT
MAX814L, V
CC
rising
MAX814N, V
CC
rising
50
48
Low
High
2.4
-1.0
1
70
73
4.93
4.83
4.68
V
1.0
1.12
50
0.8
I
SOURCE
= 800µA
I
SINK
= 3.2mA
V
CC
-1.5
0.4
0.3
0.3
2.00
s
ns
V
µA
µs
mV
V
140
V
CC
-1.5
0.4
V
RT
MAX814L, MAX815L
MAX814N, MAX815N
4.75
4.65
4.50
0
200
250
MIN
1.0
1.2
TYP
MAX
5.5
5.5
75
85
4.85
4.75
4.60
mV
ms
V
V
UNITS
V
µA
2
_______________________________________________________________________________________
±1% Accuracy, Low-Power, +3V and +5V
µP Supervisory Circuits
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.)
PARAMETER
MR Pull-Up Current
MR Pulse Width
MR Input Threshold
MR to RESET Out Delay
PFI Input Threshold
PFI Input Current
LOW LINE, PFO, WDO
Assertion Delay
SYMBOL
I
MR
t
MR
V
MRLO
V
MRHI
t
MD
V
PFI
I
PFI
(Note 2)
Low
High
(Note 3)
V
CC
= 5.0V
2.45
-15.00
2.50
+6.0
200
0.7 x V
CC
250
2.55
+35.00
MR = 0V
CONDITIONS
MIN
70
150
1.1
TYP
MAX
240
UNITS
µA
ns
V
ns
V
nA
µs
MAX814/MAX815/MAX816
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.)
PARAMETER
Operating Voltage Range
Supply Current
Reset Threshold
RESET IN Threshold
RESET IN Input Current
Reset Threshold Hysteresis
Reset Pulse Width
t
RS
V
OH
RESET Output Voltage
V
OL
V
OH
V
OL
V
OH
V
OL
RESET, WDO, PFO, LOW LINE
Output Voltage
V
OH
V
OL
V
OL
Watchdog Timeout Period
t
WD
V
RT
(max) < V
CC
< 3.6V;
MAX814T, MAX816
4.5V < V
CC
< 5.5V;
MAX814T, MAX816
V
RT
(max) < V
CC
< 3.6V
4.5V < V
CC
< 5.5V
I
SOURCE
= 500µA
I
SINK
= 1.2mA
I
SOURCE
= 800µA
I
SINK
= 3.2mA
I
SOURCE
= 500µA
I
SINK
= 1.2mA
I
SOURCE
= 800µA
I
SINK
= 3.2mA
V
CC
-1.5
0.4
0.3
0.3
1.12
2.00
s
0.8 x V
CC
0.3
V
V
CC
-1.5
0.4
140
0.8 x V
CC
0.3
V
SYMBOL
V
CC
I
SUPPLY
V
RT
V
RIT
I
RT
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
MAX816C
MAX816E
MAX816
3.00
3.00
1.683
1.678
-15
1.700
1.700
+6
0
200
250
CONDITIONS
MIN
1.0
1.2
TYP
MAX
5.5
5.5
75
85
3.06
3.08
1.717
1.722
+35
UNITS
V
µA
V
V
nA
mV
ms
T
A
= 0°C to +70°C, V
CC
= 1.0V, I
SINK
= 50µA
T
A
= -40°C to +85°C, V
CC
= 1.2V, I
SINK
= 100µA
MAX815T
_______________________________________________________________________________________
3
±1% Accuracy, Low-Power, +3V and +5V
µP Supervisory Circuits
MAX814/MAX815/MAX816
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.)
PARAMETER
WDI Pulse Width
SYMBOL
t
WP
MAX815T
V
RT
(max) < V
CC
<
3.6V; MAX815T
WDI Input Threshold
V
WDI
V
CC
= 5.0V; MAX815T
WDI Input Current
MR to WDO High Delay
LOW LINE to RESET Differential
Threshold
LOW LINE Threshold
MR Pullup Current
MR Pulse Width
MR Input Threshold
MR to RESET Out Delay
(Note 3)
PFI Input Threshold
PFI Input Current
I
WDI
t
WDO
∆V
LL
V
LLT
I
MR
t
MR
V
MRLO
V
MRHI
t
MD
V
PFI
I
PFI
CONDITIONS
V
RT
(max) < V
CC
< 3.6V
4.5V < V
CC
< 5.5V
Low
High
Low
High
2.4
-1.0
1
50
48
V
RT
(max) < V
CC
< 3.6V
4.5V < V
CC
< 5.5V
70
110
500
150
1.1
0.7 x V
CC
750
250
1.666
-15.00
1.700
+6.0
1.734
+35.00
70
73
3.163
240
370
+1.0
µA
µs
mV
V
µA
ns
V
ns
V
nA
0.7 x V
CC
0.8
MIN
100
50
0.8
V
TYP
MAX
UNITS
ns
WDI = V
CC
or 0V, MAX815T
MAX815T (Note 1)
V
CC
falling, MAX814TC
V
CC
falling, MAX814TE
V
CC
rising
MR = 0V
V
RT
(max) < V
CC
< 3.6V
4.5V < V
CC
< 5.5V
Low
High
V
RT
(max) < V
CC
< 3.6V
4.5V < V
CC
< 5.5V
V
CC
= 3.3V, 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.
4
_______________________________________________________________________________________
±1% Accuracy, Low-Power, +3V and +5V
µP Supervisory Circuits
MAX814/MAX815/MAX816
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
V
CC
SUPPLY CURRENT vs. TEMPERATURE
3V PARTS (MAX814T/MAX815T, MAX816)
MAX814-01
V
CC
SUPPLY CURRENT vs. TEMPERATURE
5V PARTS (MAX814/MAX815K, L, N)
MAX814-02
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX814-03
70
65
V
CC
SUPPLY CURRENT (µA)
60
55
50
45
40
35
30
-60
-40 -20
0
20
40
60
V
CC
= 2.5V
V
CC
= 3.3V
V
CC
= 5.0V
70
65
V
CC
SUPPLY CURRENT (µA)
60
55
50
45
40
35
30
V
CC
= 3.3V
V
CC
= 5.0V
200
RESET TIMEOUT PERIOD (ms)
195
V
CC
= 3.3V
190
185
V
CC
= 5.0V
180
175
-60
-40 -20
0
20
40
60
80 100
-60
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
80 100
TEMPERATURE (°C)
RESET-COMPARATOR PROPAGATION
DELAY vs. TEMPERATURE
MAX814-04
PFI THRESHOLD vs. TEMPERATURE
3V PARTS (MAX814T/MAX815T, MAX816)
MAX814-05
PFI THRESHOLD vs. TEMPERATURE
5V PARTS (MAX814/MAX815K, L, N)
2.540
2.530
PFI THRESHOLD (V)
2.520
2.510
2.500
2.490
2.480
2.470
2.460
2.450
MAX814-06
40
100mV OVERDRIVE
(V
RT
- V
CC
)
1.715
1.710
1.705
PFI THRESHOLD (V)
1.700
1.695
1.690
1.685
1.680
1.675
2.550
PROPAGATION DELAY (µs)
35
30
25
20
15
-60 -40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
1.670
-60
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
-60
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
LOW-LINE TO RESET THRESHOLD
vs. TEMPERATURE (V
CC
RISING)
MAX814-10
LOW-LINE TO RESET THRESHOLD
vs. TEMPERATURE (V
CC
FALLING)
LOW-LINE TO RESET THRESHOLD (mV)
68
66
64
62
60
58
56
54
52
50
0
-60
-40 -20
0
20
40
60
80 100
MAX814-09
LOW-LINE COMPARATOR
PROPAGATION DELAY vs. TEMPERATURE
100mV OVERDRIVE
(V
LLT
- V
CC
)
MAX814-11
70
LOW-LINE TO RESET THRESHOLD (mV)
68
66
64
62
60
58
56
54
52
50
-60
-40 -20
0
20
40
60
70
60
50
PROPAGATION DELAY (µs)
40
30
20
10
80 100
-60
-40 -20
0
20
40
60
80 100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
Embedded System
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