Texas Instruments LF347N/PB

Overview

LF347N/PB from Texas Instruments is a quad JFET-input operational amplifier optimized for high-speed, low-input-bias-current applications including precision integrators, sample-and-hold circuits, and D/A converter buffers. It delivers 4 MHz gain-bandwidth, 13 V/μs slew rate, 5 mV max input offset voltage, and 50 pA typical input bias current across the 0°C to 70°C commercial temperature range.

For engineers reviewing the LF347N/PB datasheet, LF347N/PB pinout, LF347N/PB application, or LF347N/PB equivalent, key selection criteria include its JFET-input architecture enabling high-impedance signal conditioning, wide supply range (±18 V), and compatibility with legacy LM124/LM148 layouts in instrumentation and test equipment designs.

Technical Context

The LF347N/PB implements four independent high-voltage JFET input stages with internally trimmed offset voltage using BI-FET II™ technology, enabling stable DC performance without external nulling. Its differential input stage supports ±30 V differential voltage and ±15 V common-mode range under ±15 V supplies.

Each amplifier features individual zener biasing for operation down to ±4.5 V supplies, while maintaining functional gain-bandwidth and slew rate. The device exhibits low 1/f noise corner at 50 Hz and 0.01 pA/√Hz input noise current, supporting precision AC and DC-coupled signal paths.

Key Specifications

Pinout & Package

LF347N/PB is housed in a 14-pin plastic dual in-line package (PDIP-N), 0.300-inch width, with standard through-hole mounting and JEDEC MO-019AC outline. Pin 1 is identified by a notch or dot at the top-left corner when viewed from the top with pins facing downward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL074CP and OPA4134UA, the LF347N/PB provides the best balance of low input bias current, moderate offset voltage, and cost-effective PDIP packaging for legacy-compatible industrial designs requiring proven reliability over decades of field use.

Availability

LF347N/PB is available at Aetrix Electronics and suitable for precision instrumentation, test equipment, and industrial control systems requiring stable component supply with long-term lifecycle support and traceable sourcing.

Supply support for LF347N/PB 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 delivering analog and embedded processing solutions with emphasis on reliability, longevity, and broad application support across industrial, automotive, and consumer markets.

The LF347N/PB belongs to TI's legacy BI-FET II™ op-amp family, engineered specifically for high-input-impedance, low-drift analog signal conditioning in cost-sensitive, high-volume industrial systems.

FAQ

What is the maximum supply voltage rating for LF347N/PB?

The LF347N/PB has an absolute maximum supply voltage rating of ±18 V. Operation beyond this limit risks permanent damage. For reliable long-term performance, TI specifies recommended operating conditions at ±15 V, where all key parameters-including gain-bandwidth, slew rate, and output swing-are fully characterized and guaranteed across the 0°C to 70°C temperature range. Always observe derating curves for elevated ambient temperatures.

Does LF347N/PB require external offset nulling?

No, the LF347N/PB does not require external offset nulling. It uses internal trimming via the BI-FET II™ process to achieve a maximum input offset voltage of 5 mV at 25°C, with a temperature coefficient of 10 μV/°C. This eliminates the need for potentiometers or external compensation networks in most precision applications, simplifying PCB layout and improving production yield for the LF347N/PB.

Can LF347N/PB drive capacitive loads directly?

The LF347N/PB can drive moderate capacitive loads (≤100 pF) without instability when configured as a unity-gain buffer, as verified in typical performance plots. For larger loads, TI recommends adding a small isolation resistor (10–100 Ω) in series with the output to maintain phase margin. Driving heavy capacitive loads directly may cause peaking or oscillation due to the amplifier's 4 MHz GBW and output stage limitations-always verify stability under actual load conditions for the LF347N/PB.

Is LF347N/PB pin-compatible with LM124 or LM148?

The LF347N/PB is pin-compatible with the LM148 quad op-amp (same 14-pin PDIP layout and pin functions), allowing direct drop-in replacement in existing designs. It is not pin-compatible with the LM124, which uses a different pinout (14-pin SOIC or PDIP but with distinct power and output assignments). When upgrading from LM148 to LF347N/PB, no PCB changes are required-only verification of supply voltage margins and thermal dissipation.

What is the input common-mode voltage range for LF347N/PB?

The LF347N/PB supports an input common-mode voltage range of ±15 V when operated with ±15 V supplies, meaning both inputs can swing from −15 V to +15 V relative to ground. This exceeds the supply rails in the positive direction (up to V+), enabling true rail-to-rail input capability. Exceeding the negative common-mode limit (below V−) forces the output high; exceeding both limits simultaneously also forces high output, but no latch-up occurs-the LF347N/PB recovers immediately upon return to valid range.