STMicroelectronics LM124DT

Overview

LM124DT from STMicroelectronics is a quad operational amplifier in SO14 package, designed for single-supply industrial signal conditioning. It delivers 1.3 MHz gain bandwidth, 100 dB large-signal voltage gain, and operates from 3 V to 30 V single supply (or ±1.5 V to ±15 V dual supply), with input common-mode range extending to ground-enabling direct interfacing with sensors and microcontroller ADCs in battery-powered instrumentation.

For engineers reviewing the LM124DT datasheet, LM124DT pinout, LM124DT application, or LM124DT equivalent, key selection criteria include its rail-to-rail input capability (0 V to V_CC−1.5 V), low 375 µA/amplifier supply current, 20 nA input bias current, 3 mV max input offset voltage at 25 °C, and −55 °C to +125 °C extended temperature rating for harsh-environment analog front-ends.

Technical Context

The LM124DT integrates four independent high-gain op-amps with internal frequency compensation, enabling stable unity-gain operation without external components. Its PNP-input stage enables true ground-sensing input common-mode range and low input bias current (20 nA typ.), while the output stage supports ±40 mA sourcing/sinking with rail-compatible swing under load.

It features internally compensated dominant-pole architecture yielding 1.3 MHz GBP at V_CC = 30 V, 100 dB open-loop gain (A_vd) at 25 °C, and 70–80 dB CMRR across temperature-optimized for DC-coupled amplification, active filtering, and precision summing in cost-sensitive industrial control systems where thermal drift and power efficiency are critical.

Key Specifications

Pinout & Package

LM124DT is housed in a 14-lead SOIC (SO14) package with standard 1.27 mm pitch, 8.75 mm × 4.0 mm body, and exposed pad not present (unlike QFN variant). Pin 4 is V_CC− (ground for single supply), Pin 11 is V_CC+, and each amplifier has dedicated inverting/non-inverting inputs and output pins arranged per industry-standard quad op-amp layout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM224ADT and LM324DT, the LM124DT uniquely combines military-grade temperature range (−55 °C to +125 °C) with proven reliability in long-life industrial systems, while maintaining pin compatibility and baseline performance-making it the default choice for ruggedized analog signal chains where thermal margin is non-negotiable.

Availability

LM124DT is available at Aetrix Electronics and suitable for industrial sensor interfaces, programmable logic controller (PLC) analog input modules, and battery-powered environmental data loggers requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for LM124DT 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in analog, power, microcontrollers, and MEMS technologies for industrial, automotive, and consumer markets.

The LM124 series belongs to ST's legacy precision analog portfolio, engineered specifically for cost-effective, high-reliability quad op-amp applications in industrial automation, test equipment, and sensor signal conditioning where wide supply range and ground-sensing capability are essential.

FAQ

What is the maximum output current capability of LM124DT per channel?

Each amplifier in the LM124DT can source or sink up to 40 mA continuously into a 2 kΩ load, as verified by Figure 5 (Output Current Limitation) and Table 3 (I_source/I_sink) in DS0985 Rev 8. This drive strength supports direct interface with LEDs, relays, and low-impedance filters without external buffers-though simultaneous full-load operation across all four channels requires careful thermal management due to 400 mW total package dissipation limit.

Does LM124DT support true rail-to-rail input or output operation?

No-LM124DT features rail-to-rail *input* (common-mode range includes ground and extends to V_CC−1.5 V), but its output swing is limited to approximately 1.5 V from each rail under load. For example, with V_CC = 5 V and 2 kΩ load, VOH ≈ 3.5 V and VOL ≈ 20 mV (Table 3, DS0985 Rev 8). This is sufficient for driving 12-bit+ ADCs but insufficient for direct 0–5 V DAC output buffering without level-shifting.

Can LM124DT be used with a single 3.3 V supply in modern low-voltage systems?

Yes-LM124DT is fully specified down to 3 V single supply (Table 2), and its input common-mode range includes ground, making it compatible with 3.3 V microcontrollers and sensors. At 3.3 V, typical supply current drops to ~0.7 mA total (0.175 mA/amplifier), and GBP remains usable (~1 MHz), though output swing reduces to ~1.8 V high and ~0.1 V low into 2 kΩ-adequate for many IoT sensor nodes where precision is secondary to ultra-low power.

How does the LM124DT's ESD rating compare to newer alternatives like TSB572?

LM124DT has 250 V HBM ESD rating (Table 7), significantly lower than TSB572's 4 kV HBM. This reflects its legacy process node; while adequate for controlled assembly environments, it requires stricter handling and board-level protection (e.g., series resistors, TVS diodes) in field-deployed equipment. ST explicitly positions TSB572 as a 36 V, automotive-qualified successor with enhanced ESD, accuracy, and lower power-making it preferable for new designs where robustness is paramount.