MAX6369MAX6374

Features:

 Precision Watchdog Timer for Critical
    µP Applications
 Pin-Selectable Watchdog Timeout Periods
 Pin-Selectable Watchdog Startup Delay Periods
 Ability to Change Watchdog Timing Characteristics
    Without Power Cycling
 Open-Drain or Push-Pull Pulsed Active-Low
    Watchdog Output
 Watchdog Timer Disable Feature
 +2.5V to +5.5V Operating Voltage 
8µA Low Supply Current 
No External Components Required
 Miniature 8-Pin SOT23 Package


Application

Embedded Control Systems
Industrial Controllers
Critical µP and Microcontroller (µC) Monitoring
Automotive
Telecommunications
Networking


Pinout




Specifications

Terminal Voltage (with respect to GND)
   V_CC.....................................................................- 0.3V to +6V
   WDI .....................................................................-0.3V to +6V
   ,WDO (Open Drain: MAX6369/71/73) .................  -0.3V to +6V
   ,WDO (Push-Pull: MAX6370/72/74  .......  -0.3V to (V_CC + 0.3V)
SET0, SET1, SET2 ................................      -0.3V to (V_CC + 0.3V)
Maximum Current, Any Pin (input/output)...........................20mA
Continuous Power Dissipation (T_A = +70°C)
SOT23-8 (derate 8.75mW/°C above +70°C)...............  700mW
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 Rise or Fall Rate......................................................0.05V/µs


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.



Description

The MAX6369MAX6374 are pin-selectable watchdog timers that supervise microprocessor (µP) activity and signal when a system is operating improperly. During normal operation, the microprocessor should repeatedly toggle the watchdog input (WDI) before the selected watchdog timeout period elapses to demonstrate that the system is processing code properly. If the µP does not provide a valid watchdog input transition before the
timeout period expires, the supervisor asserts a watchdog (,WDO) output to signal that the system is not executing the desired instructions within the expected time frame. The watchdog output pulse of MAX6369MAX6374 can be used to reset the µP or interrupt the system to warn of processing errors.

The MAX6369MAX6374 are flexible watchdog timer supervisors that can increase system reliability through notification of code execution errors. The family offers several pin-selectable watchdog timing options to match a wide range of system timing applications:
• Watchdog startup delay: provides an initial delay
   before the watchdog timer is started.
• Watchdog timeout period: normal operating watch-
   dog timeout period after the initial startup delay.
• Watchdog output/timing options: open drain (100ms)
   or push-pull (1ms).

The MAX6369MAX6374 operate over a +2.5V to +5.5V supply range and are available in miniature 8-pin SOT23 packages.