AS1977-T

Overview

The AS1977-T is an ultra-low current comparator manufactured by ams-OSRAM USA INC. in a 5-pin SOT23 package. It features an open-drain output capable of being pulled beyond VCC to a maximum of 6V above VEE, making it suitable for logic-level translation. The device operates on a supply voltage range of 1.8V to 5.5V with a typical supply current of 200nA at 1.8V and 0.21µA at 5V. It includes built-in internal hysteresis of 3mV and supports input common-mode voltages extending 200mV beyond the rails.

Feature Summary

• Open-drain output stage allows voltage extension beyond the positive supply rail
• Ultra-low supply current consumption ensures extended battery life in portable devices
• Built-in internal hysteresis prevents output oscillation from noisy or slow input signals
• Input common-mode voltage range extends slightly beyond the power supply rails

Applications

• Battery monitoring and management systems
• Logic-level translation between different voltage domains
• Threshold detectors and discriminators
• Mobile communication devices and PDAs

Procurement Notes

Verify the specific ordering suffix '-T' corresponds to tape and reel packaging rather than tube packaging when sourcing components. Confirm that the manufacturer designation aligns with ams-OSRAM USA INC. as the authorized supplier. Ensure the component meets RoHS3 compliance standards required for modern assembly processes. Cross-reference the part marking 'ASJA' to validate authenticity upon receipt.

Selection Notes

Select the AS1977-T over the push-pull variant when wired-OR logic configurations are required or when the output voltage must exceed the positive supply rail. This model is optimal for applications requiring low standby current and minimal external components due to integrated hysteresis. Consider the open-drain topology for interfacing with microcontrollers operating at different voltage levels without additional level-shifting circuitry.

Part Context

This component belongs to the AS1976/AS1977 family of ultra-low current comparators designed for space-limited, low-power applications. While the AS1976 provides a push-pull output, the AS1977 variant specifically offers an open-drain configuration. Both share identical electrical characteristics regarding input bias, offset voltage, and supply current requirements within the specified temperature range.

Replacement Considerations

Public confirmed substitute part numbers: None identified.