MAX951ESA+

Overview

The MAX951ESA+ is an ultra-low-power, single-supply integrated circuit combining a micro-power operational amplifier, a comparator, and a 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 input and output capabilities, internal ±3mV comparator hysteresis for clean switching, and a 1.2V ±2% bandgap reference. Designed for battery-powered applications, it maintains excellent DC characteristics across the -40°C to +85°C temperature range.

Feature Summary

• Combines op amp, comparator, and reference in one 8-pin package
• Ultra-low 7μA typical supply current for extended battery life
• Rail-to-rail inputs and outputs for maximum dynamic range
• Internal 1.2V ±2% bandgap reference and comparator hysteresis

Applications

• Battery-powered portable instruments and terminals
• Low-frequency local-area alarms and detectors
• Photodiode preamplifiers and sensor interfaces
• Infrared receivers for remote controls
• Smoke detectors and safety sensors

Procurement Notes

Verify the specific suffix 'ESA' confirms the 8-pin SOIC package and industrial temperature range (-40°C to +85°C). Confirm RoHS compliance status via the manufacturer's latest documentation, as ordering suffixes may indicate environmental certifications. Ensure the design accounts for the single-supply operation requirements specified in the datasheet.

Selection Notes

Select the MAX951ESA+ when a combined solution for amplification, threshold detection, and voltage referencing is required in space-constrained designs. It is ideal for high-impedance sensor buffering due to low input bias current. Consider the unity-gain stability of the op amp section for direct feedback configurations without external compensation components.

Part Context

This component belongs to the MAX951–MAX954 family of ultra-low-power mixed-signal ICs manufactured by Analog Devices Inc./Maxim Integrated. The family differentiates models based on op amp gain stability (unity-gain vs. decompensated) and the presence of an internal reference. The MAX951 specifically integrates the reference and unity-gain stable op amp.

Replacement Considerations

Official substitutes within the same family include the MAX952ESA+, which offers a decompensated op amp option for higher bandwidth applications while retaining the reference and comparator functions.

FAQ

What is the function of the REF pin on the MAX951?

The REF pin provides access to the internal 1.2V ±2% bandgap reference voltage. On the MAX951, this reference is also internally connected to the inverting input of the comparator.

Does the MAX951 require external bypass capacitors?

Power-supply bypass capacitors are not strictly required if the supply impedance is low, but it is good practice to bypass VDD with a 0.1μF capacitor to ground. The reference output should not be bypassed.

How does the internal hysteresis benefit the comparator?

The internal ±3mV hysteresis increases noise immunity and ensures clean output switching even when processing slow-moving input signals, minimizing parasitic feedback through the power supplies.