The MAX13037/MAX13038 automotive contact monitor
and level shifters monitor and debounce eight remote
mechanical switches and assert an interrupt (active-low INT) if a
switch changes state. The state of each switch is sampled
through an SPI™ interface by reading the status
register. Any switch can be prohibited from asserting an
interrupt by writing to the command register. Four of the
switch inputs are intended for ground-connected
switches (IN0–IN3) and the other four inputs (IN4–IN7)
are programmable in groups of two for either ground-connected
or battery-connected switches. Two switch inputs (IN0, IN1) have direct level-shifted outputs (DO0, DO1) to be used for PWM or other timing-based signals.
Switch input thresholds are set to 50% of the voltage
applied to BATREF. The threshold hysteresis is set by
connecting an external resistor from HYST to ground.
The MAX13037/MAX13038 supply an adjustable wetting
current to each closed switch to clean mechanical
switch contacts that are exposed to adverse conditions.
The MAX13037/MAX13038 feature a low dropout (LDO)
linear regulator capable of supplying up to 150mA of
current. The MAX13037 LDO has an output voltage of
+5V, whereas the MAX13038 has an output voltage of
+3.3V. The MAX13037/MAX13038 also feature a watchdog
timer and an open-drain reset output with
adjustable timing.
The MAX13037/MAX13038 operate with a +6V to +26V
battery voltage applied to BAT. The MAX13037/MAX13038 are available in a 6mm x 6mm, 36-pin TQFN package and operate over the automotive -40°C to
+125°C temperature range.
Key Features
Applications/Uses
+6V to +26V Operating Voltage Range
+42V Compatibility on BAT
Switch Inputs Withstand Reverse Battery
150mA LDO, +5V (MAX13037) or +3.3V (MAX13038)
Ultra-Low Operating Current 28µA (typ) in 64ms Scan Mode with LDO ON
Resistor Adjustable Switching Hysteresis
Watchdog and Reset
Built-In Switch Debouncing
Interrupt Output
Immunity to Transients
High Modularity
Thermal Protection
±8kV HBM ESD Protection on IN0–IN7 Without External Components
Two Inputs (IN0, IN1) Programmable as Direct Outputs
Four Inputs (IN4–IN7) Programmable for BAT or GND Related Switches
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