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MAX6369–MAX6374
Pin-Selectable Watchdog Timers
General Description
The MAX6369–MAX6374 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 can be used to reset the μP or interrupt the system to warn of processing errors.
The MAX6369–MAX6374 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 watchdog timeout period after the initial startup delay.
●● Watchdog output/timing options: open drain (100ms) or push-pull (1ms).
The MAX6369–MAX6374 operate over a +2.5V to +5.5V supply range and are available in miniature 8-pin SOT23 packages.
Benefits and 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
●● AEC-Q100 Qualified (MAX6369KA/V+ and MAX6374KA/V+ Only)
Applications
●● Embedded Control Systems ●● Industrial Controllers ●● Critical μP and Microcontroller (μC) Monitoring ●● Automotive ●● Telecommunications ●● Networking
Functional Diagram
VCC WDI
MAX6369–MAX6374
TRANSITION DETECTOR
EN
SET 2 SET 1 SET 0
CONTROL LOGIC
ENABLE
CLEAR
SET WATCHDOG TIMEOUT
SET STARTUP DELAY
WATCHDOG TIMER CIRCUITRY
GND
OUT
OUTPUT
WDO
19-1676; Rev 9; 3/19
MAX6369–MAX6374
Pin-Selectable Watchdog Timers
Absolute Maximum Ratings
Terminal Voltage (with respect to GND) VCC......................................................................-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 (VCC + 0.3V) SET0, SET1, SET2............................... -0.3V to (VCC + 0.3V) Maximum Current, Any Pin (input/output)...........................20mA
Continuous Power Dissipation .