19-2349; Rev 3; 12/05
Low-Cost, Power-On Reset
and Watchdog Controllers
General Description
The MAX698/MAX699 monitor the +5V supply in micro-
processor (µP) and digital systems. They supply a
RESET
pulse of at least 140ms duration on power-up,
power-down, and during low-voltage brownout condi-
tions. Circuit reliability is increased at reduced cost by
eliminating all external components and adjustments.
The MAX699 includes all features of the MAX698, but
also provides a watchdog input to monitor microproces-
sor activity. The
RESET
output goes low if the watchdog
input (WDI) is not toggled within 1 second. The watch-
dog feature can be disabled by leaving WDI open.
Both parts are supplied in 8-lead PDIP and 16-lead
0.3in wide small outline (SO) packages and are speci-
fied from 0°C to +70°C for C grade devices and -40°C
to +85°C for E devices. The SO versions, with more
pins than the 8-lead PDIP, have additional outputs not
available in DIP packages. These are RESET (without
inversion) and watchdog output (WDO).
♦
Precision Voltage Monitor
♦
Power-OK/Reset Time Delay
♦
Watchdog Timer
♦
Minimum Component Count
Features
MAX698/MAX699
Ordering Information
PART*
MAX698CPA
MAX698CWE
MAX698EPA
MAX698EWE
MAX699CPA
MAX699CWE
MAX699EPA
MAX699EWE
TEMP RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 PDIP
16 Wide SO
8 PDIP
16 Wide SO
8 PDIP
16 Wide SO
8 PDIP
16 Wide SO
Applications
Computers
Controllers
Intelligent Instruments
Automotive Systems
Critical µP Power Monitoring
*
Devices are available in both leaded and lead-free packag-
ing. Specify lead free by adding the + symbol at the end of the
part number when ordering.
Pin Configuration
TOP VIEW
V
CC
1
8
GND
Typical Operating Circuit
V
CC
2
MAX698
MAX699*
7
RESET
GND
3
6
N.C. (WDI)*
GND
4
5
N.C.
+5V
+5V
DIP
1
V
CC
GND
8
GND
1
16
RESET
2
V
CC
MAX698
RESET
7
TO
µP
RESET
INPUT
V
CC
2
15
RESET
V
CC
3
MAX698
MAX699*
14
N.C. (WDO)*
3
GND
N.C.
6
GND
4
13
N.C.
4
GND
N.C.
5
N.C.
5
12
N.C.
N.C.
6
11
N.C. (WDI)*
N.C.
7
10
N.C.
N.C.
8
SO
9
GND
* PIN LABELS IN ( ) ARE FOR MAX699 ONLY
________________________________________________________________
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.
Low-Cost, Power-On Reset
and Watchdog Controllers
MAX698/MAX699
ABSOLUTE MAXIMUM RATINGS
V
CC
........................................................................-0.3V to +6.0V
Input Voltage (with respect to GND)
WDI,
WDO,
RESET,
RESET
..…………………………-0.3V to V
CC
Operating Temperature Range
C Suffix………………………………………………0°C to +70°C
E Suffix ......……………………………………….-40°C to +85°C
Rate of Rise, V
CC
.................………………………………100V/µs
Power Dissipation (T
A
= +70°C)
8-Pin PDIP (derated 5mW/°C above +70°C).....………400mW
16-Pin SO (derated 7mW/°C above +70°C) ................600mW
Storage Temperature Range .............................-65°C to +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
= +5V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Operating Voltage Range
Supply Current
Power-Up Reset Deassertion
Power-Up Reset Assertion
Hysteresis
Reset Output Pulse Width
RESET
OUTPUT (Open Drain)
RESET OUTPUT (SO Package
Only)
WDO
Output (MAX699 SO
Package Only)
MAX699 Watchdog Timeout
Period
MAX699 Minimum WDI Input
Pulse Width
MAX699 WDI Input Threshold
MAX699 WDI Input Current
V
CC
= +5V
WDI = V
CC
WDI = 0V
-50
Locic-low
Logic-high
3.8
20
-15
50
Output low
Output high
Output low
Output high
Output low
Output high
I
SINK
= 1.6mA, V
CC
= 4.4V
I
SOURCE
= 1µA, V
CC
= 5V
I
SINK
= 1.6mA, V
CC
= 5V
I
SOURCE
= 1µA, V
CC
= 4.4V
I
SINK
= 1.6mA, V
CC
= 5V
I
SOURCE
= 1µA, V
CC
= 4.4V
3.5
1.00
200
0.8
1.6
2.25
3.5
0.4
3.5
0.4
140
T
A
= full
T
A
= full
4.50
4.4
40
500
0.4
4.65
CONDITIONS
T
A
= full
MIN
3.0
TYP
MAX
5.5
5
4.75
UNITS
V
mA
V
V
mV
ms
V
V
V
s
ns
V
µA
2
_______________________________________________________________________________________
Low-Cost, Power-On Reset
and Watchdog Controllers
Pin Description
PIN
SO
1, 4, 9
2, 3
5–8, 10–14
PDIP
3, 4, 8
1, 2
5, 6
NAME
GND
V
CC
N.C.
Chip Power Ground
+5V Sense Input and MAX698/MAX699 Chip Power
No Connection
(MAX699 Only.) A three-level input. If WDI remains high or low for
more than the watchdog timeout period,
RESET
pulses low (WDO
also goes low on the MAX699 SO package). If WDI is unconnected,
the watchdog circuit is disabled.
(MAX699 Only.) Goes low when WDI remains high or low for more
than the watchdog timeout period.
WDO
is set high at the next WDI
transition. If WDI is unconnected or at midsupply,
WDO
remains high.
WDO
also remains high when V
CC
falls below 4.4V.
Goes low when V
CC
falls below internally set threshold (see the
Electrical Characteristics
table).
Goes high when V
CC
falls below internally set threshold.
FUNCTION
MAX698/MAX699
10
6
WDI (MAX699 Only)
14
—
WDO
(MAX699 Only)
15
16
7
—
RESET
RESET
WDI*
WATCHDOG
TIMER
WDO*
RESET
TIMER
RESET
V
CC
RESET*
V
CC
POWER-ON
RESET
4.65V
MAX698
MAX699
GND
*WDI ON MAX699 ONLY
RESET ON SO PACKAGE ONLY
WDO ON SO MAX699 ONLY
Figure 1. Block Diagram
_______________________________________________________________________________________
3
Low-Cost, Power-On Reset
and Watchdog Controllers
MAX698/MAX699
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
Chip Topography
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
4
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Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
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