STMicroelectronics LM324APT

Overview

LM324APT from STMicroelectronics is a low-power quad operational amplifier in TSSOP-14 package, designed for single-supply operation from 3 V to 30 V or dual supplies (±1.5 V to ±15 V). It delivers 1.3 MHz gain bandwidth, 100 dB large-signal voltage gain, and rail-to-rail input common-mode range including ground - enabling precision signal conditioning in industrial sensor interfaces and 24 V PLC analog front-ends.

For engineers reviewing the LM324APT datasheet, LM324APT pinout, LM324APT application, or LM324APT equivalent, key selection criteria include its 375 µA/amplifier supply current, 20 nA input bias current, 3 mV max input offset voltage (A-grade), and guaranteed operation across 0 °C to 70 °C ambient temperature.

Technical Context

The LM324APT integrates four independent high-gain op-amps with internal frequency compensation, supporting unity-gain-stable operation. Its input stage uses PNP transistors enabling true ground-sensing capability and wide common-mode input range (0 V to V_CC − 1.5 V at 25 °C).

Output stage provides symmetrical sourcing/sinking capability (≥20 mA source, ≥12 mA sink at V_CC = 15 V), with output swing within 20 mV of ground and up to 27 V (at V_CC = 30 V, R_L = 10 kΩ) - suitable for driving ADC reference buffers and active filters without level-shifting.

Key Specifications

Pinout & Package

TSSOP-14 (Thin Shrink Small Outline Package, 4.9 mm × 6.4 mm × 1.05 mm body height) with exposed pad not electrically connected; RoHS-compliant, ECOPACK2 certified.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM324DT, the LM324APT offers superior thermal performance (100 °C/W vs. 103 °C/W) and tighter V_os, while TSB572IDT provides significantly improved DC precision and automotive qualification at higher cost and power.

Availability

LM324APT is available at Aetrix Electronics and suitable for industrial sensor interfaces, PLC analog input modules, battery-powered data loggers, and DC motor current monitors requiring stable component supply across production lifecycles.

Supply support for LM324APT 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, designing and manufacturing microcontrollers, power management ICs, analog components, and MEMS sensors for industrial, automotive, and consumer markets.

The LM324x series belongs to ST's general-purpose analog portfolio, engineered specifically for cost-sensitive, wide-supply industrial signal conditioning where reliability, ease of use, and long-term availability are critical.

FAQ

Is LM324APT pin-compatible with LM324DT?

Yes - both share identical TSSOP-14 and SO-14 pinouts per Figure 1 of DS0985 Rev 8. Pin functions (e.g., Pin 1 = Inverting Input Amp 1, Pin 11 = V_CC+) are electrically and physically identical. No PCB redesign is needed when migrating between packages.

What is the maximum junction temperature for continuous operation?

The absolute maximum junction temperature is 150 °C. At ambient 70 °C and TSSOP-14 R_thJA = 100 °C/W, maximum allowable power dissipation is 800 mW. With 1.5 mA total supply current at 30 V, dissipation is ~45 mW - well within safe margin even under worst-case load conditions.

Does LM324APT support rail-to-rail output swing?

No - it does not achieve true rail-to-rail output. At V_CC = 30 V and R_L = 10 kΩ, high-level output reaches 27 V (3 V below rail); low-level output sinks to 20 mV above ground. This is sufficient for most 24 V industrial interfaces but insufficient for 0–3.3 V logic-level signaling without external level shift.

Can LM324APT drive capacitive loads directly?

Stable with ≤100 pF capacitive load at unity gain, per Figure 10 (open-loop frequency response) and Figure 14 (small-signal pulse response) in DS0985. For larger loads (e.g., ADC input capacitance >100 pF), an isolation resistor (10–100 Ω) between output and capacitor is recommended to prevent peaking or oscillation.