The MAX49017 features a built-in 1.252V reference that is factory-trimmed to an initial accuracy of 1% and better than 2.5% over the entire temperature range. The common-mode voltage range of this family extends 200mV beyond the rails, allowing signals slightly beyond the rails to trigger the comparator. The 2.5mV internal hysteresis ensures clean output switching even with slow moving input signals. Large internal output drivers allow rail-to-rail output swing with up to ±2mA loads.
The output stage employs a unique design that minimizes supply current surges while switching, virtually eliminating supply glitches typical of many other comparators. The MAX49017 has a push-pull output stage that sinks as well as sources current.
The input common-mode voltage range extends from -0.2V to VDD + 0.2V. The comparator operates at any differential input voltage within these limits. Input bias current is typically ±1nA if the input voltage is between the supply rails. Comparator inputs are protected from overvoltage by internal ESD-protection diodes connected to the supply rails. As the input voltage exceeds the supply rails, these ESD-protection diodes become forward biased and begin to conduct increasing input bias current (see the Input Bias Current vs. Input Common-Mode Voltage and Input Bias Current vs. Input Differential Voltage graphs in the Typical Operating Characteristics section).
The device contains a unique break-before-make output stage capable of rail-to-rail operation with up to ±2mA loads. Many comparators consume orders of magnitude more current during switching than during steady-state operation. In the Typical Operating Characteristics section, the Supply Current vs. Output Transition Frequency graphs show the minimal supply-current increase as the output switching frequency approaches 1kHz. This characteristic reduces the need for power-supply filter capacitors to reduce glitches created by comparator switching currents. In automotive applications, this characteristic results in a substantial increase in car battery life.
The MAX49017 comes with an internal voltage reference that has initial accuracy of ±1%. The device’s internal reference has a typical temperature coefficient of 15ppm/°C over the full -40°C to +125°C temperature range. The reference is a very-low-power bandgap cell, with a maximum 10kΩ output impedance. The REF pin can source and sink up to 100nA to external circuitry. For applications that need increased drive, buffer REF with a low input-bias current op amp such as the MAX44265. The internal reference voltage of the MAX49017 is stable with a capacitive load of 0pF to 100pF and values greater than 0.1µF (with an unstable region from 100pF to 0.1µF). To minimize unwanted feedback from pin OUTA to the REF pin through package parasitics, an 0.1µF bypass capacitor is recommended to be added on the REF pin.