AS1971

Overview

The AS1971 is a low-voltage single comparator from the AS1970-AS1975 series, manufactured by austriamicrosystems AG (now ams AG). It operates on a single supply of 2.5V to 5.5V or dual supplies of ±1.25V to ±2.75V. The device features an open-drain output capable of being pulled beyond VCC up to 5.5V > VEE. Key electrical parameters include a quiescent supply current of 8.5µA per comparator, a typical propagation delay of 300ns, and an internal hysteresis of 3mV. It utilizes a 5-pin SOT23 package.

Feature Summary

• Open-drain output stage allows voltage extension beyond VCC for logic-level translation
• Internal hysteresis ensures clean switching with slow input signals
• Low power consumption with minimal supply current requirements
• Common-mode input voltage range extends 250mV above and below supply rails

Applications

• Battery-powered systems
• Zero-crossing detectors
• Window comparators
• Logic-level translators
• Threshold detectors and discriminators

Procurement Notes

Verify that the ordering suffix matches the required delivery form, as the base part number may be available in tape and reel or tube configurations depending on the specific variant requested. Confirm the manufacturer source, noting that technical content originates from austriamicrosystems AG, now operating under ams AG. Ensure compatibility with the specified 5-pin SOT23 package dimensions during PCB layout.

Selection Notes

Select the AS1971 when an open-drain output is required for interfacing with different logic voltage levels or bipolar-to-unipolar conversion. Choose this model over push-pull variants if the application demands pulling the output voltage higher than the positive supply rail. Consider the 3mV internal hysteresis for noise immunity without external components.

Part Context

The AS1971 belongs to the AS1970-AS1975 family of low-voltage comparators designed for 3V and 5V applications. This family includes single, dual, and quad configurations with either push-pull or open-drain outputs. The series is engineered for space-limited applications requiring low power consumption and high performance in portable and mobile devices.

Replacement Considerations

The AS1970 serves as the push-pull equivalent within the same package. For dual-channel requirements, the AS1973 provides a similar open-drain configuration in an 8-pin MSOP package. Quad-channel equivalents are available as the AS1975 in a 14-pin TSSOP package.