Texas Instruments LM324MT

Overview

LM324MT from Texas Instruments is a quad, low-power, internally frequency-compensated operational amplifier designed for single-supply operation from 3 V to 32 V (or ±1.5 V to ±16 V). It delivers 1 MHz unity-gain bandwidth, 100 dB DC open-loop gain, 700 μA supply current per amplifier, 2 mV input offset voltage, and rail-to-rail input common-mode range including ground - enabling direct sensing of signals referenced to ground in battery-powered industrial sensors and signal-conditioning circuits.

For engineers reviewing the LM324MT datasheet, LM324MT pinout, LM324MT application, or LM324MT equivalent, this page provides verified specifications, validated package mapping (SOIC-14), confirmed pin functions, real-world application context for transducer amplification and DC gain blocks, and two technically documented alternative parts with explicit functional and thermal differences.

Technical Context

The LM324MT uses a PNP-input stage enabling true ground-sensing capability and differential input voltage tolerance up to the full supply rail. Its class-A/class-B output stage dynamically adjusts bias to support both sourcing (up to 40 mA) and sinking (up to 20 mA) while maintaining low quiescent current across 0°C to +70°C operating temperature.

Internally compensated for unity-gain stability, it exhibits temperature-compensated input bias current (45 nA typ. at 25°C) and input offset voltage drift (7 µV/°C), with CMRR of 65–85 dB and PSRR of 65–100 dB - making it suitable for precision DC-coupled amplification where supply rejection and common-mode immunity are critical.

Key Specifications

Pinout & Package

LM324MT is supplied in a 14-pin SOIC (Small Outline Integrated Circuit) package with nominal body dimensions of 8.65 mm × 3.91 mm and standard JEDEC MS-012 footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad operational amplifier applications.

Compared with LM324MT, LM324DR offers identical functionality in a variant packaging format optimized for high-volume production, while LM2902DT extends junction temperature capability to −40°C to +85°C - making it suitable for harsh environments but requiring validation of system-level thermal margins.

Availability

LM324MT is available at Aetrix Electronics and suitable for industrial sensor interfaces, battery-powered instrumentation, and embedded analog signal conditioning requiring stable component supply across long product lifecycles.

Supply support for LM324MT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of heritage in precision op amp design and manufacturing.

The LM324MT belongs to TI's legacy general-purpose op amp product line, engineered specifically for cost-sensitive, single-supply industrial and consumer applications demanding reliability, wide voltage operation, and ground-sensing capability.

FAQ

What is the maximum operating temperature range for the LM324MT?

The LM324MT is rated for operation from 0°C to +70°C ambient temperature. This commercial-grade specification aligns with its intended use in indoor industrial controls, consumer electronics, and non-automotive embedded systems. Exceeding +70°C may cause parametric degradation in input offset voltage and gain accuracy. For extended temperature operation, consider the LM2902DT variant, which supports −40°C to +85°C. Always verify thermal dissipation using the 88°C/W junction-to-ambient thermal resistance value under actual board layout conditions.

Does the LM324MT support true rail-to-rail input and output operation?

The LM324MT supports rail-to-rail input common-mode range - specifically from 0 V to V₊ −1.5 V - allowing direct connection of ground-referenced signals without biasing. However, its output swing is limited to 0 V to V₊ −1.5 V (with RL = 2 kΩ), so it does not achieve true rail-to-rail output. This behavior stems from its bipolar PNP input and class-A/B output stage. For applications requiring full rail-to-rail I/O, TI's TLV2464 or MCP6004 families offer alternatives - but LM324MT remains optimal where ground-sensing and low quiescent current are prioritized over output headroom.

Can the LM324MT be used as a comparator?

Yes, the LM324MT can be used as a comparator in non-critical applications due to its open-loop configuration and high DC gain (100 dB). However, it lacks internal hysteresis and has relatively slow response (1 V/μs slew rate), making it unsuitable for high-speed or noise-prone environments. When used as a comparator, add external positive feedback to introduce hysteresis and prevent oscillation near threshold. For dedicated comparator functions, TI's LM393 or TLV3701 provide faster propagation delay, built-in hysteresis options, and lower input offset - but LM324MT remains viable for low-frequency threshold detection in cost-constrained designs.

What is the typical supply current draw of the LM324MT at 5 V operation?

At V₊ = 5 V and TA = 25°C, the LM324MT draws 700 μA per amplifier, totaling 2.8 mA for all four channels. This value remains essentially independent of supply voltage across the full 3–32 V range, as confirmed in Section 6.6 of the official datasheet. The low and stable current draw makes LM324MT ideal for battery-powered devices such as portable data loggers and handheld test equipment where runtime optimization is critical. Note that total current increases slightly at elevated temperatures - up to 1.2 mA per amplifier at maximum operating temperature.

Is the LM324MT pin-compatible with other members of the LMx24 family?

Yes, the LM324MT is fully pin-compatible with LM324-N, LM224-N, LM124-N, and LM2902-N in SOIC-14 and PDIP-14 packages. All share identical pin numbering, electrical pin functions, and footprint. Differences lie only in specified operating temperature ranges (LM324MT: 0°C to +70°C; LM2902-N: −40°C to +85°C) and certain AC parameters like CMRR and PSRR. This compatibility enables direct substitution during prototyping or qualification - though thermal and long-term stability validation is required when upgrading to extended-temperature variants like LM2902DT.