The MAX16997AAUA+ is a high voltage watchdog timer with adjustable timeout delay in 8 pin μMAX package. It is a microprocessor (μP) supervisory circuit for high input voltage and low quiescent current applications. This device detects downstream circuit failures and provides switchover to redundant circuitry. The MAX16997A has four independent inputs for reset and watchdog functions. SWT and SRT inputs independently set timeout periods of watchdog and reset timers through external capacitors. RESETIN/EN monitor voltages at respective inputs. A resistive voltage divider sets the reset threshold. It generates one output signal (complementary ENABLE) based on voltage level at EN and signal at WDI. It does not has RESET complementary output. The MAX16997A watchdog timer starts timing when voltage at EN becomes higher than the preset threshold voltage level. Each time EN rises above preset threshold voltage, the initial watchdog timeout period is 8 times the normal watchdog timeout period.
Wide 5V to 40V input voltage range
Automotive temperature range from -40°C to 125°C
18μA quiescent current (typical at +125°C)
Capacitor adjustable timeout period for watchdog and reset
External voltage monitoring
Car battery compatible EN input
TTL and CMOS compatible open-drain outputs
Watch dog window size is 100%, WDI narrow pulse immunity
Maximum open-drain enable output voltage is 28V
Power-on reset input threshold voltage of 1.255V and reset timeout period of 5ms
(EN)
