19-1086; Rev 1; 11/05
8-Pin µP Supervisory Circuits
with ±1.5% Reset Accuracy
_______________General Description
The MAX801/MAX808 microprocessor (µP) supervisory
circuits monitor and control the activities of +5V µPs by
providing backup-battery switchover, low-line indica-
tion, and µP reset. Additional features include a watch-
dog for the MAX801 and CMOS RAM write protection
for the MAX808.
The MAX801/MAX808 offer a choice of reset-threshold
voltage (denoted by suffix letter): 4.675V (L), 4.575V
(N), and 4.425V (M). These devices are available in
8-pin DIP and SO packages.
____________________________Features
♦
Precision Voltage Monitoring, ±1.5% Reset
Accuracy
♦
200ms Power-OK/Reset Time Delay
♦
RESET Output (MAX808)
RESET and RESET Outputs (MAX801)
♦
Watchdog Timer (MAX801)
♦
On-Board Gating of Chip-Enable Signals (MAX808):
Memory Write-Cycle Completion
3ns CE Gate Propagation Delay
♦
1µA Standby Current
♦
Power Switching:
250mA in V
CC
Mode
20mA in Battery-Backup Mode
♦
MaxCap™/SuperCap™ Compatible
♦
RESET Guaranteed Valid to V
CC
= 1V
♦
Low-Line Threshold 52mV Above Reset
Threshold
MaxCap is a trademark of The Carborundum Corp.
SuperCap is a trademark of Baknor Industries.
MAX801L/M/N, MAX808L/M/N
________________________Applications
Computers
Controllers
Intelligent Instruments
Critical µP Power Monitoring
Portable/Battery-Powered Equipment
Embedded Systems
______________Ordering Information
PART*
TEMP RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
8 Plastic DIP
8 SO
8 Plastic DIP
8 SO
8 CERDIP**
8 Plastic DIP
8 SO
8 Plastic DIP
MAX801_CPA
MAX801_CSA
MAX801_EPA
MAX801_ESA
MAX801_MJA
MAX808_CPA
MAX808_CSA
MAX808_EPA
Pin Configurations appear at end of data sheet.
__________Typical Operating Circuit
+5V
0.1μF
0.1μF
V
CC
OUT
POWER FOR
CMOS RAM
NMI
RESET
μP
POWER
BATT
0.1μF
LOWLINE
RESET
MAX808_ESA
-40°C to +85°C
8 SO
MAX808_MJA
-55°C to +125°C
8 CERDIP**
*These
parts offer a choice of reset threshold voltage. From the
table below, select the suffix corresponding to the desired thresh-
old and insert it into the blank to complete the part number.
**Contact
factory for availability and processing to MIL-STD-883.
Devices in PDIP, SO and µMAX packages 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. Lead free
not available for CERDIP package.
RESET THRESHOLD (V)
SUFFIX
L
N
M
MIN
4.60
4.50
4.35
TYP
4.675
4.575
4.425
MAX
4.75
4.65
4.50
1
µP SYSTEM
MAX808
CE IN
CE OUT
GND
FROM I/O SYSTEM OR
ADDRESS DECODER
TO CMOS RAM
________________________________________________________________
Maxim Integrated Products
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.
8-Pin µP Supervisory Circuits
with ±1.5% Reset Accuracy
MAX801L/M/N, MAX808L/M/N
ABSOLUTE MAXIMUM RATINGS
Input Voltage (with respect to GND)
V
CC
.......................................................................-0.3V to +6V
V
BATT
....................................................................-0.3V to +6V
All Other Pins........................................-0.3V to (V
OUT
+ 0.3V)
Input Current
V
CC
Peak ..........................................................................1.0A
V
CC
Continuous ............................................................500mA
I
BATT
Peak.....................................................................250mA
I
BATT
Continuous ............................................................50mA
GND ................................................................................50mA
All Other Inputs ...............................................................50mA
Output Current
OUT Peak..........................................................................1.0A
OUT Continuous............................................................500mA
All Other Outputs ............................................................50mA
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW
SO (derate 5.88mW/°C above +70°C) .........................471mW
CERDIP (derate 8.00mW/°C above +70°C) .................640mW
Operating Temperature Ranges
MAX801_C_A/MAX808_C_A...............................0°C to +70°C
MAX801_E_A/MAX808_E_A ............................-40°C to +85°C
MAX801_MJA/MAX808_MJA.........................-55°C to +125°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+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
= 4.6V to 5.5V for the MAX80_L, V
CC
= 4.5V to 5.5V for the MAX80_N, V
CC
= 4.35V to 5.5V for the MAX80_M; V
BATT
= 2.8V;
T
A
= T
MIN
to T
MAX
. Typical values are at V
CC
= 5V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
Operating Voltage Range
V
CC
, BATT (Note 1)
I
OUT
= 25mA
V
OUT
in Normal Operating
Mode
V
CC
= 4.5V
I
OUT
= 250mA, MAX80_C/E
I
OUT
= 250mA, MAX80_M
V
CC
= 3V, V
BATT
= 2.8V, I
OUT
= 100mA
V
CC
to OUT
On-Resistance
V
OUT
in Battery-Backup
Mode
BATT to OUT
On-Resistance
Supply Current in Normal
Operating Mode
(excludes I
OUT
)
Supply Current in Battery-
Backup Mode (excludes
I
OUT
) (Note 2)
BATT Standby Current
(Note 3)
Battery-Switchover
Threshold
Battery-Switchover
Hysteresis
2
MAX80_C/E
V
CC
= 4.5V,
I
OUT
= 250mA MAX80_M
V
CC
= 3V, I
OUT
= 100mA
V
BATT
= 4.5V, I
OUT
= 20mA
V
CC
= 0V
V
BATT
= 2.8V, I
OUT
= 10mA
V
BATT
= 2.0V, I
OUT
= 5mA
V
BATT
= 4.5V, I
OUT
= 20mA
V
CC
= 0V
MAX801
MAX808
T
A
= +25°C
V
CC
= 0V,
V
BATT
= 2.8V T
A
= T
MIN
to T
MAX
V
BATT
= 2.8V, I
OUT
= 10mA
V
BATT
= 2.0V, I
OUT
= 5mA
V
CC
- 0.38
V
CC
- 0.45
V
CC
- 0.25
V
CC
- 0.12
1.0
1.2
V
BATT
- 0.16
V
BATT
- 0.25 V
BATT
- 0.12
V
BATT
- 0.20 V
BATT
- 0.08
8
12
16
68
48
0.4
MAX80_C/E
MAX80_M
-0.1
-1.0
V
BATT
+ 0.05
V
BATT
50
25
40
110
µA
90
1
5
50
0.1
1.0
µA
V
mV
µA
Ω
V
1.5
1.8
2.5
Ω
SYMBOL
CONDITIONS
MIN
0
TYP
X
V
CC
- 0.02
V
CC
- 0.25
V
MAX
5.5
UNITS
V
V
BATT
+ 0.2V T
A
= +25°C
≤
V
CC
T
A
= T
MIN
to T
MAX
Power-up
V
BATT
= 2.8V
Power-down
_______________________________________________________________________________________
8-Pin µP Supervisory Circuits
with ±1.5% Reset Accuracy
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 4.6V to 5.5V for the MAX80_L, V
CC
= 4.5V to 5.5V for the MAX80_N, V
CC
= 4.35V to 5.5V for the MAX80_M; V
BATT
= 2.8V;
T
A
= T
MIN
to T
MAX
. Typical values are at V
CC
= 5V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
RESET AND LOW-LINE
MAX80_L
Reset Threshold
Reset-Threshold Hysteresis
LOWLINE
to
RESET
Threshold Voltage
LOWLINE
Threshold,
V
CC
Rising
V
CC
to
RESET
Delay
V
CC
to
LOWLINE
Delay
RESET
Active Timeout
Period
V
LR
V
CC
falling
MAX80_L
V
LL
t
RD
t
LL
t
RP
MAX80_N
MAX80_M
V
CC
falling at 1mV/µs
V
CC
falling at 1mV/µs
V
CC
rising
I
SINK
= 50µA,
V
CC
= 1.0V, MAX80_C
V
BATT
= 0V,
V
CC
= 1.2V, MAX80_E/M
V
CC
falling
I
SINK
= 3.2mA, V
CC
= 4.25V
I
SOURCE
= 0.1mA
RESET
Output
Short-Circuit Current
RESET Output Voltage
(MAX801)
RESET Output Short-
Circuit Current (MAX801)
LOWLINE
Output Voltage
LOWLINE
Output
Short-Circuit Current
Watchdog Timeout Period
Minimum Watchdog Input
Pulse Width
WDI Threshold Voltage
(Note 4)
WDI Input Current
V
IH
V
IL
RESET deasserted, WDI = 0V
RESET deasserted, WDI = V
CC
-50
-10
16
50
I
SC
I
SC
I
SC
Output sink current, V
CC
= 4.25V
Output source current
I
SINK
= 3.2mA
I
SOURCE
= 5mA, V
CC
= 4.25V
Output sink current
Output source current, V
CC
= 4.25V
I
SINK
= 3.2mA, V
CC
= 4.25V
I
SOURCE
= 5mA, V
CC
= 4.25V
Output sink current, V
CC
= 4.25V
Output source current
1.12
V
IL
= 0.8V, V
IH
= 0.75V x V
CC
100
0.75 x V
CC
0.8
V
CC
- 1.5
40
20
1.6
2.24
V
CC
- 1.5
55
15
0.4
V
CC
- 1.5
0.1
V
CC
- 0.1
40
1.6
0.4
mA
V
mA
V
mA
140
30
V
RST
V
CC
rising
and falling
MAX80_N
MAX80_M
4.600
4.500
4.350
4.675
4.575
4.425
13
52
4.73
4.63
4.48
17
17
200
280
0.3
0.3
0.4
V
70
4.81
4.71
4.56
µs
µs
ms
V
4.750
4.650
4.500
mV
mV
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX801L/M/N, MAX808L/M/N
RESET
Output Voltage
WATCHDOG TIMER (MAX801)
t
WD
sec
ns
V
µA
_______________________________________________________________________________________
3
8-Pin µP Supervisory Circuits
with ±1.5% Reset Accuracy
MAX801L/M/N, MAX808L/M/N
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 4.6V to 5.5V for the MAX80_L, V
CC
= 4.5V to 5.5V for the MAX80_N, V
CC
= 4.35V to 5.5V for the MAX80_M; V
BATT
= 2.8V;
T
A
= T
MIN
to T
MAX
. Typical values are at V
CC
= 5V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
CE
IN Leakage Current
CE
IN to
CE
OUT
Resistance (Note 5)
CE
OUT Short-Circuit
Current (RESET Active)
CE
IN to
CE
OUT
Propagation Delay (Note 6)
CE
OUT Output Voltage
High (RESET Active)
RESET
to
CE
OUT Delay
(Note 7)
SYMBOL
V
CC
= 4.25V
Enabled mode, V
CC
= V
RST
(max)
V
CC
= 4.25V,
CE
OUT = 0V
V
CC
= 5V, C
LOAD
= 50pF,
50Ω source-impedance driver
V
CC
= 4.25V, I
OUT
= 2mA
V
CC
= 0V, I
OUT
= 10µA
V
CC
falling,
CE
IN = 0V
3.5
V
BATT
- 0.1
V
BATT
18
CONDITIONS
MIN
TYP
±0.00002
75
15
3
8
MAX
±1
150
UNITS
µA
Ω
mA
ns
V
µs
CHIP-ENABLE GATING (MAX808)
Note 1:
Either V
CC
or V
BATT
can go to 0V if the other is greater than 2V.
Note 2:
The supply current drawn by the MAX80_ from the battery (excluding I
OUT
) typically goes to 15µA when (V
BATT
- 0.1V) <
V
CC
< V
BATT
. In most applications, this is a brief period as V
CC
falls through this region (see
Typical Operating
Characteristics).
Note 3:
“+” = battery-discharging current, “-” = battery-charging current.
Note 4:
WDI is internally connected to a voltage divider between V
CC
and GND. If unconnected, WDI is typically driven to 1.8V,
disabling the watchdog function.
Note 5:
The chip-enable resistance is tested with V
CE
IN
= V
CC
/ 2 and I
CE
IN
= 1mA.
Note 6:
The chip-enable propagation delay is measured from the 50% point at
CE
IN to the 50% point at
CE
OUT.
Note 7:
If
CE
IN goes high,
CE
OUT goes high immediately and stays high until reset is deasserted and
CE
IN is low.
__________________________________________Typical Operating Characteristics
(V
CC
= 5V, V
BATT
= 2.8V, no load, T
A
= +25°C, unless otherwise noted.)
V
CC
SUPPLY CURRENT vs. TEMPERATURE
(NORMAL OPERATING MODE)
MAX801/808-01
BATTERY SUPPLY CURRENT vs.
TEMPERATURE (BATTERY-BACKUP MODE)
MAX801/808-02
MAX808
CHIP-ENABLE PROPAGATION DELAY
vs. TEMPERATURE
MAX801/808-03
75
V
CC
SUPPLY CURRENT (μA)
70
65
60
55
50
MAX808
45
40
-55 -35 -15
5
25
MAX801
3.0
BATTERY SUPPLY CURRENT (μA)
2.5
2.0
1.5
1.0
0.5
0
6
5
4
3
2
1
0
45 65 85 105 125
-60 -40 -20 0
20 40 60 80 100 120 140
PROPAGATION DELAY (ns)
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
4
_______________________________________________________________________________________
8-Pin µP Supervisory Circuits
with ±1.5% Reset Accuracy
MAX801L/M/N, MAX808L/M/N
____________________________Typical Operating Characteristics (continued)
(V
CC
= 5V, V
BATT
= 2.8V, no load, T
A
= +25°C, unless otherwise noted.)
MAX808
CHIP-ENABLE PROPAGATION DELAY
vs. CE OUT LOAD CAPACITANCE
MAX801/808-04
BATT to OUT ON-RESISTANCE
vs. TEMPERATURE
V
BATT
TO V
OUT
ON-RESISTANCE (Ω)
V
CC
TO V
OUT
ON-RESISTANCE (Ω)
V
CC
= 0V
I
OUT
= 10mA
25
V
BATT
= 2.0V
MAX801/808-05
V
CC
to OUT ON-RESISTANCE
vs. TEMPERATURE
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
-60 -40 -20 0
20 40 60 80 100 120 140
I
OUT
= 250mA
MAX801/808-06
8
50Ω DRIVER
PROPAGATION DELAY (ns)
6
30
1.6
20
4
15
V
BATT
= 2.8V
2
10
V
BATT
= 4.5V
5
0
0
50
C
LOAD
(pF)
100
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
RESET THRESHOLD
vs. TEMPERATURE
MAX801/808-07
RESET TIMEOUT PERIOD
vs. TEMPERATURE (V
CC
RISING)
MAX801/808-08
LOWLINE to RESET THRESHOLD
vs. TEMPERATURE (V
CC
FALLING)
LOWLINE TO RESET THRESHOLD (mV)
70
60
50
40
30
20
10
0
-60 -40 -20 0
20 40 60 80 100 120 140
MAX801/808-09
4.70
4.65
RESET THRESHOLD (V)
4.60
4.55
4.50
4.45
4.40
-60 -40 -20 0
MAX80_M
MAX80_N
280
RESET TIMEOUT PERIOD (ms)
260
240
220
200
180
160
140
-60 -40 -20 0
80
MAX80_L
20 40 60 80 100 120 140
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
LOWLINE THRESHOLD
vs. TEMPERATURE (V
CC
RISING)
MAX801/808-10
LOWLINE COMPARATOR PROPAGATION
DELAY vs. TEMPERATURE (V
CC
FALLING)
MAX801/808-11
RESET COMPARATOR PROPAGATION
DELAY vs. TEMPERATURE (V
CC
FALLING)
V
CC
FALLING AT 1mV/µs
35
PROPAGATION DELAY (µs)
30
25
20
15
10
5
0
MAX801/808-12
4.80
4.75
LOWLINE THRESHOLD (V)
4.70
4.65
4.60
4.55
4.50
4.45
4.40
-60 -40 -20 0
MAX80_M
MAX80_N
MAX80_L
40
V
CC
FALLING AT 1mV/µs
35
PROPAGATION DELAY (µs)
30
25
20
15
10
5
0
40
20 40 60 80 100 120 140
-60 -40 -20 0
20 40 60 80 100 120 140
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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