Datasheet
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
(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)
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.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range V
CC
T
A
= 0°C to +70°C 2.25 5.5 V
Supply Current I
SUPPLY
WDI unconnected
V
CC
= 5.5V 10 24
µA
V
CC
= 2.5V 4 12
Undervoltage Lockout Threshol
d
UVLO (Note 2) 2.19 V
Watchdog Pulse Period t
PP
(Note 3) 140 200 280 ms
WDO Output Voltage
V
OH
I
SOURCE
= 30µA, V
CC
= 2.3V 0.8
×
V
CC
V
V
OL
I
SINK
= 1.2mA, V
CC
= 2.1V 0.3
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
WDI Input Voltage (Note 5)
V
IL
0.3
×
V
CC
V
V
IH
0.7
×
V
CC
WDI Input Current (Note 6)
WDI = V
CC
, time average 120 160
µA
WDI = 0, time average
-20 -15
MAX6814 5-Pin Watchdog Timer Circuit
www.maximintegrated.com
Maxim Integrated
│
2
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.
Absolute Maximum Ratings
Electrical Characteristics