MAX951ESA

Overview

The MAX951ESA is an ultra-low-power, single-supply integrated circuit combining a micro-power operational amplifier, comparator, and precision reference within an 8-pin SOIC package. It operates from a supply voltage range of 2.7V to 7V with a typical supply current of 7μA. The device features rail-to-rail outputs for both the op amp and comparator, ensuring compatibility with various logic families. The internal comparator includes ±3mV hysteresis for clean switching, while the op amp offers unity-gain stability.

Feature Summary

• Combines a micro-power op amp, comparator, and internal 1.2V bandgap reference in a compact 8-pin package
• Ultra-low power consumption with typical supply current of 7μA across the full operating temperature range
• Rail-to-rail output stages on both the operational amplifier and comparator for maximum dynamic range
• Internal comparator hysteresis eliminates power-supply glitches and ensures noise immunity during signal transitions

Applications

• Battery-powered portable instruments and terminals
• Low-frequency local-area alarms and detectors
• Photodiode preamplifiers and infrared receivers for remote controls
• Smoke detectors and safety sensors utilizing high-impedance inputs
• Smart cards requiring low-voltage operation and minimal power drain

Procurement Notes

Verify the specific suffix 'ESA' corresponds to the 8-pin SOIC package and -40°C to +85°C industrial temperature range. Confirm RoHS compliance status as indicated by the '+' suffix in the ordering information. Ensure design requirements align with the single-supply voltage constraints and input common-mode ranges specified in the electrical characteristics.

Selection Notes

Select the MAX951ESA when a combined solution for amplification, comparison, and voltage referencing is required in space-constrained designs. This part is suitable for applications demanding ultra-low quiescent current to extend battery life. Consider the internal reference accuracy and comparator hysteresis if external components for these functions would otherwise be necessary.

Part Context

The MAX951ESA belongs to the MAX951–MAX954 family of ultra-low-power, single-supply devices manufactured by Analog Devices Inc./Maxim Integrated. These components integrate multiple analog functions into a single small footprint, targeting portable and battery-operated systems. The family differentiates models based on op amp gain stability and the presence of an internal reference, with the MAX951 featuring unity-gain stability and an internal reference.

Replacement Considerations

Direct replacements within the same package and pinout include the MAX951EPA (Plastic DIP) and MAX951EUA (µMAX). For applications not requiring the internal reference, the MAX953ESA offers similar op amp and comparator performance without the reference output. Verify thermal dissipation limits and package dimensions when substituting between SOIC, DIP, and µMAX formats.

FAQ

What is the function of the REF pin on the MAX951ESA?

The REF pin provides access to the internal 1.20V ±2% bandgap reference voltage. In the MAX951, this reference is also internally connected to the inverting input of the comparator.

How does the MAX951ESA handle input signals near the supply rails?

Both the op amp and comparator feature a common-mode input voltage range that extends from the negative supply rail (VSS) to within 1.6V of the positive rail (VDD). The outputs are capable of swinging rail-to-rail.

Is the op amp in the MAX951ESA stable at unity gain?

Yes, the op amp in the MAX951 is internally compensated to be unity-gain stable, allowing it to be used as a voltage follower or in low-gain configurations without oscillation.