Texas Instruments LM348N

Overview

LM348N from Texas Instruments is a quadruple, independent, high-gain, internally compensated operational amplifier designed for general-purpose analog signal conditioning. It delivers 0.6 mA typical supply current per amplifier, ≤6 mV input offset voltage at 25°C, and ±12 V common-mode input range with ±15 V supplies - used in industrial sensor front-ends, audio preamplifier stages, and DC-coupled instrumentation circuits.

For engineers reviewing the LM348N datasheet, LM348N pinout, LM348N application, or LM348N equivalent, key selection considerations include its PDIP-14 package thermal resistance (80°C/W), guaranteed operation from 0°C to 70°C, Class AB output stage with overload protection, and interchangeability with legacy µA741-based designs requiring quad op-amp functionality.

Technical Context

The LM348N implements four fully independent op-amp channels in a single monolithic IC, each featuring internal frequency compensation for unity-gain stability. Its architecture includes input/output overload protection and a Class AB output stage enabling rail-to-rail output swing under light loads.

It operates from dual supplies of ±4 V to ±18 V, supports full-range common-mode input up to ±12 V, and maintains ≥70 dB CMRR and ≥77 dB SVR across temperature - making it suitable for precision DC amplification where drift and power efficiency are balanced.

Key Specifications

Pinout & Package

LM348N uses a 14-pin plastic dual in-line package (PDIP-N), with 8.0 mm body width, 19.15 mm length, and 5.08 mm max height. Thermal resistance θ_JA is 80°C/W, supporting moderate-power dissipation in through-hole PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM348N, LM324N eliminates need for dual supplies but sacrifices bipolar signal fidelity and overload robustness, while TL084CN offers superior speed and input impedance at the cost of increased design complexity and reduced fault tolerance.

Availability

LM348N is available at Aetrix Electronics and suitable for industrial sensor interfaces, audio preamplification stages, and DC-coupled instrumentation circuits requiring stable component supply across extended production lifecycles.

Supply support for LM348N 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 founded in 1930, specializing in analog, embedded processing, and digital signal technologies for industrial, automotive, and communications markets.

The LM348N belongs to TI's legacy linear amplifier product line, engineered for reliability and interoperability in cost-sensitive, long-lifecycle analog systems where proven performance outweighs cutting-edge specs.

FAQ

What is the maximum operating temperature range for the LM348N?

The LM348N is specified for operation from 0°C to +70°C ambient temperature. This commercial-grade rating makes it suitable for indoor industrial controls, consumer audio equipment, and laboratory instruments where environmental extremes are not expected. The device's absolute maximum junction temperature is 150°C, and its PDIP package has a thermal resistance of 80°C/W, allowing safe operation at full supply voltage under typical board-level airflow conditions. Always verify actual board temperature rise during thermal validation of the LM348N.

Does the LM348N require external compensation capacitors?

No, the LM348N is internally compensated and stable at unity gain without external capacitors. Its 1 MHz unity-gain bandwidth and 60° phase margin are guaranteed across temperature and supply conditions. This eliminates tuning effort in standard inverting and non-inverting configurations. However, if used in high-gain (>100×) or capacitive-load scenarios (>100 pF), small series resistors (e.g., 10–100 Ω) at the output may be added to isolate the load and preserve stability - a practice confirmed in TI's application notes for the LM348N.

Can the LM348N replace the µA741 in existing designs?

Yes, the LM348N is explicitly designed to be interchangeable with the µA741 in quad-amplifier configurations, offering improved specifications including lower supply current (0.6 mA vs. ~1.7 mA per amp), lower input offset voltage (≤6 mV vs. ≤7.5 mV), and enhanced input/output overload protection. Its pinout matches the µA741-based quad topology, and its internal compensation eliminates the need for external compensation networks required by many µA741 variants. Engineers can directly substitute LM348N into µA741-based schematics without layout changes.

What is the input bias current specification for the LM348N?

The LM348N has a typical input bias current of 30 nA at 25°C, with a maximum of 400 nA across the full 0°C to +70°C operating range. This bipolar-input characteristic enables accurate amplification of signals from medium-impedance sources such as 10 kΩ potentiometers or 100 kΩ thermistor networks. For ultra-high-impedance sources (e.g., >1 MΩ), JFET-input alternatives like TL084CN offer significantly lower bias current (≈30 pA), but the LM348N remains optimal where cost, robustness, and simplicity are prioritized over extreme input impedance.

Is the LM348N RoHS compliant and lead-free?

Yes, the LM348N is RoHS compliant and lead-free, as confirmed by Texas Instruments' packaging documentation. It features NiPdAu (nickel-palladium-gold) lead finish and meets EU RoHS requirements for all 10 restricted substances, including Pb, Cd, Hg, Cr⁶⁺, and PBB/PBDE. The device is rated for peak reflow temperatures up to 260°C and carries a JEDEC moisture sensitivity level (MSL) rating appropriate for standard surface-mount assembly - though the PDIP-N variant is through-hole and exempt from MSL classification. Full compliance data is available in TI's official LM348N packaging addendum.