19-0433; Rev 4; 11/05
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
General Description
The MAX807 microprocessor (µP) supervisory circuit
reduces the complexity and number of components
needed to monitor power-supply and battery-control func-
tions in µP systems. A 70µA supply current makes the
MAX807 ideal for use in portable equipment, while a 2ns
chip-enable propagation delay and 250mA output current
capability (20mA in battery-backup mode) make it suit-
able for larger, higher-performance equipment.
The MAX807 comes in 16-pin DIP, SO, and TSSOP pack-
ages, and provides the following functions:
• µP reset. The active-low RESET output is asserted dur-
ing power-up, power-down, and brownout conditions,
and is guaranteed to be in the correct state for V
CC
down to 1V.
• Active-high RESET output.
• Manual-reset input.
• Two-stage power-fail warning. A separate low-line
comparator compares V
CC
to a threshold 52mV above
the reset threshold. This low-line comparator is more
accurate than those in previous µP supervisors.
• Backup-battery switchover for CMOS RAM, real-time
clocks, µPs, or other low-power logic.
• Write protection of CMOS RAM or EEPROM.
• 2.275V threshold detector provides for power-fail
warning and low-battery detection, or monitors a
power supply other than +5V.
• BATT OK status flag indicates that the backup-battery
voltage is above +2.275V.
• Watchdog-fault output—asserted if the watchdog input
has not been toggled within a preset timeout period.
Features
♦
Precision 4.675V (MAX807L), 4.425V (MAX807M),
or 4.575V (MAX807N) Voltage Monitoring
♦
200ms Power-OK/Reset Time Delay
♦
RESET and RESET Outputs
♦
Independent Watchdog Timer
♦
1µA Standby Current
♦
Power Switching
250mA in V
CC
Mode
20mA in Battery-Backup Mode
♦
On-Board Gating of Chip-Enable Signals;
2ns CE Gate Propagation Delay
♦
MaxCap
®
and SuperCap
®
Compatible
♦
Voltage Monitor for Power Fail
♦
Backup-Battery Monitor
♦
Guaranteed RESET Valid to V
CC
= 1V
♦
±1.5% Low-Line Threshold Accuracy 52mV above
Reset Threshold
MAX807L/M/N
Pin Configuration
TOP VIEW
PFI 1
PFO 2
V
CC
3
WDI
4
16 OUT
15 BATT OK
14 BATT
Applications
Computers
Controllers
Intelligent Instruments
Critical µP Power Monitoring
Portable/Battery-Powered Equipment
MAX807
13 BATT ON
12 CE IN
11 CE OUT
10 WDO
9
RESET
GND 5
MR
LOW LINE
RESET
6
7
8
DIP/SO/TSSOP
Ordering Information and Typical Operating Circuit appear at end of data sheet.
SuperCap is a registered trademark of Baknor Industries. MaxCap is a registered trademark of Cesiwid, Inc.
________________________________________________________________
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.
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
MAX807L/M/N
ABSOLUTE MAXIMUM RATINGS
Input Voltages (with respect to GND)
V
CC
..........................................................................-0.3V to 6V
V
BATT
.......................................................................-0.3V to 6V
All Other Inputs......................................-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
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 10.53mW/°C above +70°C) ..........842mW
Wide SO (derate 9.52mW/°C above +70°C)................762mW
CERDIP (derate 10.00mW/°C above +70°C) ...............800mW
TSSOP (derate 6.70 mW/°C above +70°C) .................533mW
Operating Temperature Ranges
MAX807_C_E ......................................................0°C to +70°C
MAX807_E_E ...................................................-40°C to +85°C
MAX807_MJE ................................................-55°C to +125°C
Storage Temperature Range .............................-65°C to +160°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
= 4.60V to 5.5V for the MAX807L, V
CC
= 4.50V to 5.5V for the MAX807N, V
CC
= 4.35V to 5.5V for the MAX807M,
V
BATT
= 2.8V, V
PFI
= 0V, T
A
= T
MIN
to T
MAX
. Typical values are tested with V
CC
= 5V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
Operating Voltage Range
V
BATT
, V
CC
(Note 1)
I
OUT
= 25mA
V
OUT
in Normal Operating
Mode
V
CC
= 4.5V
SYMBOL
CONDITIONS
MIN
0
V
CC
- 0.02
TYP
MAX
5.5
UNITS
V
I
OUT
= 250mA,
V
CC
- 0.35 V
CC
- 0.22
MAX807C/E
I
OUT
= 250mA,
V
CC
- 0.45
MAX807M
V
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)
V
CC
= 3V, V
BATT
= 2.8V, I
OUT
= 100mA
MAX807C/E
V
CC
= 4.5V,
I
OUT
= 250mA
MAX807M
V
CC
= 3V, I
OUT
= 100mA
V
BATT
= 4.5V, I
OUT
= 20mA, V
CC
= 0V
V
BATT
= 2.8V, I
OUT
= 10mA, V
CC
= 0V
V
BATT
= 2.0V, I
OUT
= 5mA, V
CC
= 0V
V
BATT
= 4.5V, I
OUT
= 20mA
V
BATT
= 2.8V, I
OUT
= 10mA
V
BATT
= 2.0V, I
OUT
= 5mA
V
CC
- 0.25 V
CC
- 0.12
1.0
1.2
V
BATT
- 0.17
V
BATT
- 0.25 V
BATT
- 0.12
V
BATT
- 0.20 V
BATT
- 0.08
8.5
12
16
70
1.4
1.8
2.5
Ω
V
25
40
110
1
5
50
0.1
Ω
µA
V
CC
= 0V, V
BATT
= 2.8V
T
A
= +25°C
MAX807C/E
MAX807M
T
A
= +25°C
-0.1
-1.0
0.4
µA
BATT Standby Current (Note 3)
V
BATT
= 2.8V, V
CC
= 3.0V
T
A
= T
MIN
to
T
MAX
Power up
Power down
µA
1.0
V
BATT
+ 0.05
V
BATT
50
0.1
2.7
V
mV
V
V
Battery-Switchover Threshold
Battery-Switchover Hysteresis
BATT ON Output, Low Voltage
BATT ON Output, High Voltage
2
V
BATT
= 2.8V
V
RST (max)
, I
SINK
= 3.2mA
V
CC
= 0V, I
SOURCE
= 0.1mA, V
BATT
= 2.8V
0.4
2
_______________________________________________________________________________________
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 4.60V to 5.5V for the MAX807L, V
CC
= 4.50V to 5.5V for the MAX807N, V
CC
= 4.35V to 5.5V for the MAX807M,
V
BATT
= 2.8V, V
PFI
= 0V, T
A
= T
MIN
to T
MAX
. Typical values are tested with V
CC
= 5V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
BATT ON Output
Short-Circuit Current
SYMBOL
CONDITIONS
MIN
TYP
70
5
4.600
4.500
4.350
4.675
4.575
4.425
13
52
4.73
4.63
4.48
26
24
140
1.12
V
IL
= 0.8V, V
IH
= 0.75 x V
CC
V
CC
= 1V,
MAX807_C
V
CC
= 1.2V,
MAX807_E/M
V
CC
- 1.5
0.1
V
CC
- 0.1
60
1.6
100
0.3
0.3
0.4
V
200
1.6
280
2.24
4.750
4.650
4.500
MAX
UNITS
mA
Sink current
Source current, V
CC
= 0V, V
BATT
= 2.8V
RESET, LOW LINE, AND WATCHDOG TIMER
MAX807L
Reset Threshold
V
RST
V
CC
rising and falling
MAX807N
MAX807M
Reset Threshold Hysteresis
LOW LINE to RESET
Threshold Voltage
LOW LINE Threshold,
V
CC
Rising
V
CC
to RESET Delay
V
CC
to LOW LINE Delay
RESET Active-Timeout Period
Watchdog-Timeout Period
Minimum Watchdog Input
Pulse Width
t
RP
t
WD
V
LR
V
CC
falling
MAX807L
MAX807N
MAX807M
V
CC
falling at 1mV/µs
V
CC
falling at 1mV/µs
V
CC
rising
MAX807L/M/N
V
mV
30
70
4.81
4.71
4.56
mV
V
LL
V
µs
µs
ms
s
ns
RESET Output Voltage
I
SINK
= 50µA,
V
BATT
= 0V, V
CC
falling
RESET Output
Short-Circuit Current
RESET Output Voltage
RESET Output
Short-Circuit Current
LOW LINE Output Voltage
LOW LINE Output
Short-Circuit Current
WDO Output Voltage
WDO Output
Short-Circuit Current
WDI Threshold Voltage
(Note 4)
WDI Input Current
I
SC
I
SC
I
SC
I
SC
V
IH
V
IL
V
IH
I
SINK
= 3.2mA, V
CC
= 4.25V
I
SOURCE
= 0.1mA
Output sink current, V
CC
= 4.25V
Output source current
I
SINK
= 3.2mA
I
SOURCE
= 5mA
Output sink current
Output source current, V
CC
= 4.25V
I
SINK
= 3.2mA, V
CC
= 4.25V
I
SOURCE
= 5mA
Output sink current, V
CC
= 4.25V
Output source current
I
SINK
= 3.2mA
I
SOURCE
= 5mA
Output sink current
Output source current
mA
0.4
V
mA
0.4
V
mA
0.4
V
mA
V
µA
V
CC
- 1.5
60
15
V
CC
- 1.5
28
20
V
CC
- 1.5
35
20
0.75 x V
CC
0.8
Reset deasserted, WDI = 0V
Reset deasserted, WDI = V
CC
-50
-10
16
50
_______________________________________________________________________________________
3
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
MAX807L/M/N
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 4.60V to 5.5V for the MAX807L, V
CC
= 4.50V to 5.5V for the MAX807N, V
CC
= 4.35V to 5.5V for the MAX807M,
V
BATT
= 2.8V, V
PFI
= 0V, T
A
= T
MIN
to T
MAX
. Typical values are tested with V
CC
= 5V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
PFI Input Threshold
PFI Hysteresis
PFI Leakage Current
PFI to PFO Delay (Note 5)
CHIP-ENABLE GATING
CE IN Leakage Current
CE IN to CE OUT Resistance
(Note 6)
CE OUT Short-Circuit Current
(RESET Active)
CE IN to CE OUT
Propagation Delay (Note 7)
CE OUT Output Voltage High
(RESET Active)
RESET to CE OUT Delay
MANUAL RESET INPUT
MR Minimum Pulse Input
MR-to-RESET Propagation
Delay
MR Threshold
MR Pullup Current
BATT OK COMPARATOR
BATT OK Threshold
BATT OK Hysteresis
LOGIC OUTPUTS
Output Voltage
(PFO, BATT OK)
Output Short-Circuit Current
V
BOK
V
IH
V
IL
MR = 0V
2.4
0.8
50
2.200
100
2.265
20
200
2.350
1
170
µs
ns
V
µA
V
mV
Disabled mode, MR = 0V
Enabled mode, V
CC
= V
RST
(max)
V
CC
= 5V, disabled mode,
CE OUT = 0, MR = 0V
V
CC
= 5V, C
LOAD
= 50pF,
50Ω source impedance driver
V
CC
= 5V,
I
OUT
= 2mA
V
CC
= 0V,
I
OUT
= 10µA
3.5
V
V
BATT
- 0.1
V
BATT
28
µs
±0.00002
75
17
2
8
±1
150
µA
Ω
mA
ns
V
OD
= 30mV, V
PFI
falling
SYMBOL
V
PFT
V
PFI
falling
V
PFI
rising
CONDITIONS
MIN
2.20
2.22
TYP
2.265
2.285
20
±0.005
14
MAX
2.33
2.35
±40
UNITS
V
mV
nA
µs
Disabled mode, MR = 0V
V
CC
falling
V
OL
V
OH
I
SC
I
SINK
= 3.2mA
I
SOURCE
= 5mA
Output sink current
Output source current
0.4
V
CC
- 1.5
35
20
V
mA
Note 1:
Either V
CC
or V
BATT
can go to 0 if the other is greater than 2.0V.
Note 2:
The supply current drawn by the MAX807 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 driven to 1.8V (typical),
disabling the watchdog function.
Note 5:
Overdrive (V
OD
) is measured from center of hysteresis band.
Note 6:
The chip-enable resistance is tested with V
CE IN
= V
CC
/2, and I
CE IN
= 1mA.
Note 7:
The chip-enable propagation delay is measured from the 50% point at CE IN to the 50% point at CE OUT.
4
_______________________________________________________________________________________
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
MAX807L/M/N
__________________________________________Typical Operating Characteristics
(V
CC
= 5V, V
BATT
= 2.8V, PFI = 0, no load, T
A
= +25°C, unless otherwise noted.)
BATTERY SUPPLY CURRENT vs.
TEMPERATURE (BATTERY-BACKUP MODE)
MAX807-02
V
CC
SUPPLY CURRENT vs. TEMPERATURE
(NORMAL OPERATING MODE)
78
V
CC
SUPPLY CURRENT (µA)
76
74
72
70
68
66
64
62
60
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
0
MAX807-01
CHIP-ENABLE PROPAGATION DELAY
vs. TEMPERATURE
MAX807-03
80
3.0
BATTERY SUPPLY CURRENT (µA)
2.5
6
5
PROPAGATION DELAY (ns)
4
3
2
1
0
2.0
1.5
1.0
0.5
-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)
BATT-TO-OUT ON-RESISTANCE
vs. TEMPERATURE
MAX807-04
V
CC
-TO-OUT ON-RESISTANCE
vs. TEMPERATURE
MAX807-05
PFI THRESHOLD
vs. TEMPERATURE (V
PFI
FALLING)
2.320
PFI THRESHOLD (V)
2.300
2.280
2.260
2.240
2.220
2.200
MAX807-06
30
BATT-TO-OUT ON-RESISTANCE (Ω)
1.6
V
CC
-TO-OUT ON-RESISTANCE (Ω)
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
-60 -40 -20 0
I
OUT
= 250mA
2.340
V
CC
= 0V
I
OUT
= 10mA
25
V
BATT
= 2.0V
20
15
V
BATT
= 2.8V
10
V
BATT
= 4.5V
5
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
20 40 60 80 100 120 140
-60 -40 -20 0
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
RESET THRESHOLD
vs. TEMPERATURE
MAX807-07
RESET TIMEOUT PERIOD
vs. TEMPERATURE (V
CC
RISING)
MAX807-08
LOW LINE -TO-RESET THRESHOLD
vs. TEMPERATURE (V
CC
FALLING)
LOW LINE-TO-RESET THRESHOLD (mV)
70
60
50
40
30
20
10
0
-60 -40 -20 0
20 40 60 80 100 120 140
MAX807-09
4.70
4.65
RESET THRESHOLD (V)
4.60
4.55
4.50
4.45
4.40
-60 -40 -20 0
MAX807M
MAX807N
280
260
RESET TIMEOUT PERIOD (ms)
240
220
200
180
160
140
-60 -40 -20 0
80
MAX807L
20 40 60 80 100 120 140
20 40 60 80 100 120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
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