OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

MAX6814XK+T

P1-P3P4-P6
________________General Description
The MAX6814 is a low-power watchdog circuit in a tiny 5-
pin SC70 package. This device improves system reliability
by monitoring the system for software code execution
errors. When the watchdog input detects a transitional
edge, the internal watchdog timer clears and restarts,
then begins counting again. If the watchdog timer
exceeds the watchdog timeout period (1.6s typ), the
active-low, push-pull watchdog output asserts for the
watchdog pulse period (140ms min) to alert the system of
the fault.
The MAX6814 consumes only 4µA of supply current and
is fully specified over the extended temperature range.
________________________Applications
Computers and Controllers
Embedded Controllers
Intelligent Instruments
Automotive Systems
Critical µP Monitoring
Features
♦ 4µA Operating Current
♦ Watchdog Timer with 1.6s Timeout
♦ 140ms (min) WDO Pulse Period
♦ Push-Pull Active-Low WDO
♦ Fully Specified Over Extended Temperature
Range
♦ No External Components
MAX6814
5-Pin Watchdog Timer Circuit
________________________________________________________________ Maxim Integrated Products 1
19-2804; Rev 2; 12/05
Ordering Information
PART
TEMP
RANGE
PIN-
PACKAGE
TOP
MARK
MAX6814XK-T
- 40°C to + 85°C
5 SC70-5 AE K
Pin Configuration
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.
Typical Operating Circuit
MAX6814
μP
V
CC
V
CC
V
CC
GND
GND
NMI
I/O
WDO
WDI
1
5
2
3
4
GND
WDI
V
CC
MAX6814
SC70-5
TOP VIEW
N.C.
WDO
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
MAX6814
5-Pin Watchdog Timer Circuit
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= +2.25V to +5.5V, T
A
= T
MIN
to T
MAX
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
(Note 1)
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.
V
CC
........................................................................-0.3V to +6.0V
All Other Pins..............................................-0.3V to (V
CC
+ 0.3V)
Input Current, WDI ..............................................................20mA
Output Current,
WDO..........................................................20mA
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SC70 (derate 3.1mW/°C above +70°C)...............247mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Operating Voltage Range V
CC
T
A
= 0°C to +70°C
2.25
5.5 V
V
CC
= 5.5V 10 24
Supply Current
I
SUPPLY
WDI unconnected
V
CC
= 2.5V 4 12
µA
Undervoltage Lockout Threshold UVLO (Note 2)
2.19
V
Watchdog Pulse Period t
PP
(Note 3)
140 200 280
ms
V
OH
I
SOURCE
= 30µA, V
CC
= 2.3V 0.8 ✕ V
CC
WDO Output Voltage
V
OL
I
SINK
= 1.2mA, V
CC
= 2.1V 0.3
V
WDO Output Short-Circuit Current
I
SOURCE
V
CC
= 3.6V (Note 4)
400
µA
Watchdog Timeout Period t
WD
1.12 1.60 2.40
s
WDI Pulse Width t
WDI
V
IL
= 0.4V, V
IH
= 0.8
✕
V
CC
50 ns
V
IL
0.3
✕
V
CC
WDI Input Voltage (Note 5)
V
IH
0.7
✕
V
CC
V
WDI = V
CC
, time average
120 160
WDI Input Current (Note 6)
WDI = 0, time average -20
-15
µA
Note 1: Overtemperature limits are guaranteed by design, production testing performed at +25°C only.
Note 2: WDO is low when V
CC
falls below the undervoltage threshold. When V
CC
rises above the undervoltage threshold, WDO goes
high after the watchdog pulse period.
Note 3: Watchdog pulse period occurs when the watchdog times out or after V
CC
rises above the undervoltage threshold.
Note 4: The WDO short-circuit current is the maximum pullup current when WDO is driven low.
Note 5: WDI is internally serviced within the watchdog period if WDI is left unconnected.
Note 6: The WDI input current is specified as the average input current when the WDI input is driven high or low. The WDI input is
designed to drive a three-stated output device with a 10µA maximum leakage current and a maximum capacitive load of
200pF. This output device must be able to source and sink at least 200µA when active.
MAX6814
5-Pin Watchdog Timer Circuit
_______________________________________________________________________________________ 3
Pin Description
__________________________________________Typical Operating Characteristics
(V
CC
= +5V, T
A
= +25°C, unless otherwise noted.)
1
3
2
6
5
4
8
7
9
-40 20 40-20 0 60 80 100 120
MAX6814 toc01
TEMPERATURE (
°
C)
SUPPLY CURRENT (mA)
V
CC
SUPPLY CURRENT
vs. TEMPERATURE
250
150
-40 -20 40 100
WDO PULSE PERIOD
vs. TEMPERATURE
170
160
180
230
240
MAX6814 toc02
TEMPERATURE (
°
C)
WDO PULSE PERIOD (ms)
020 8060
210
220
190
200
2.0
1.0
-40 -20 40 100
WATCHDOG TIMEOUT PERIOD
vs. TEMPERATURE
1.2
1.1
1.3
1.8
1.9
MAX6814 toc03
TEMPERATURE (
°
C)
WATCHDOG TIMEOUT PERIOD (s)
020 8060
1.6
1.7
1.4
1.5
PIN
NAME
FUNCTION
1 WDO
Active-Low Watchdog Output. Pulses low for 140ms (min) when the watchdog timer exceeds the watchdog
timeout period. WDO is low when V
CC
is below the UVLO threshold and remains low for 140ms (min) after
V
CC
exceeds the UVLO threshold.
2
GND Ground
3
N.C. No Connection. Leave unconnected or connect to V
CC
.
4 WDI
Watchdog Input. If WDI remains either high or low for longer than the watchdog timeout period, the internal
watchdog timer runs out and a watchdog pulse period is triggered. The internal watchdog timer clears
whenever a watchdog pulse period is asserted, or whenever WDI sees a rising or falling edge. If WDI is left
unconnected or is connected to a three-stated buffer output, the watchdog is disabled.
5
V
CC
Supply Voltage
P1-P3P4-P6

MAX6814XK+T

Mfr. #:
Buy MAX6814XK+T
Manufacturer:
Maxim Integrated
Description:
Supervisory Circuits 5-Pin Watchdog Timer Circuit
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet