Texas Instruments LF347N

Overview

LF347N from STMicroelectronics is a quad JFET-input operational amplifier in 14-pin PDIP package, rated for 0°C to +70°C operation. It delivers 16 V/µs typical slew rate, ±11 V common-mode input range, 2.5 MHz gain-bandwidth product, and 10¹² Ω input resistance-enabling precision signal conditioning in audio distribution amplifiers and active filter stages.

For engineers reviewing the LF347N datasheet, LF347N pinout, LF347N application, or LF347N equivalent, key selection criteria include its JFET-input low bias current (5 pA typ), wide supply range (±18 V max), output short-circuit protection, and channel separation of 120 dB at Av = 100-critical for multi-channel analog systems requiring minimal crosstalk and thermal stability.

Technical Context

The LF347N integrates four matched high-voltage JFET-input op-amps on a single monolithic die, combining JFET input stages with bipolar output transistors. Its internal frequency compensation ensures unity-gain stability without external components, while latch-up free operation supports robust use in mixed-signal environments.

Each amplifier features rail-to-rail compatible input common-mode range (±11 V at ±15 V supplies) and delivers ±12 V output swing into 10 kΩ. The 45° phase margin and 2.5 MHz GBP support stable closed-loop configurations up to moderate bandwidths, including second-order bandpass filters at 100 kHz with Q = 30.

Key Specifications

Pinout & Package

LF347N uses a 14-pin plastic dual in-line package (PDIP) with standard 0.3-inch body width and 2.54 mm lead pitch. Pin 1 is bottom-left corner when notch faces up.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad JFET-input op-amp applications.

Compared with TLC27M4CDR and TL084CP, LF347N offers superior input impedance and lower bias current for high-Z sources, higher slew rate than TLC27M4CDR for faster signals, and built-in latch-up immunity absent in TL084CP-making it optimal for new designs demanding precision, speed, and robustness in commercial-grade analog systems.

Availability

LF347N is available at Aetrix Electronics and suitable for audio distribution amplifiers, active bandpass filters, DC-coupled sensor interfaces, and multi-channel pulse amplifiers requiring stable component supply across production lifecycles.

Supply support for LF347N 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 analog, microcontroller, power, and MEMS products for industrial, automotive, and consumer markets.

The LF347N belongs to ST's legacy precision analog op-amp family, engineered for commercial-grade instrumentation and signal conditioning where JFET input performance, thermal stability, and multi-channel integration are essential.

FAQ

What is the maximum supply voltage for LF347N?

The absolute maximum supply voltage is ±18 V, meaning total supply span may not exceed 36 V. Operation at ±15 V is typical and ensures full specification compliance across the 0°C to +70°C temperature range. Exceeding ±18 V risks permanent damage to internal junctions, regardless of duration or load condition.

Does LF347N require external compensation capacitors?

No-LF347N features internal frequency compensation optimized for unity-gain stability. Adding external capacitors is unnecessary and may degrade phase margin or step response. The device achieves 45° phase margin and stable operation with gains ≥ 1 without any external components.

Can LF347N drive capacitive loads directly?

LF347N can safely drive up to 100 pF without instability, as verified in the datasheet's test conditions (CL = 100 pF, RL = 2 kΩ). Driving larger capacitive loads requires isolation via a series resistor (≥ 100 Ω) or a dedicated buffer stage to prevent peaking, overshoot, or oscillation due to pole-splitting effects.

Is LF347N pin-compatible with other quad op-amps like LM324?

No-LF347N uses standard 14-pin DIP pinout for quad op-amps, but differs electrically from LM324: LF347N is JFET-input (high-Z, low Ib), while LM324 is bipolar-input (lower Vio, higher Ib). Direct substitution may cause bias errors or saturation in high-impedance circuits; redesign of feedback networks is typically required.