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Home > Products > Integrated Circuits (ICs) > Linear > Instrumentation, Op Amps, Buffer Amps

STMicroelectronics LF347D

Name: LF347D
Brand: STMicroelectronics
SKU: LF347D
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LF347D

Manufacturer:: STMicroelectronics

Category:: Instrumentation, Op Amps, Buffer Amps

Package:: 14-SOIC (0.154", 3.90mm Width)

Datasheet:: LF347D.pdf

Description:: IC OPAMP JFET 4 CIRCUIT 14SO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

LF347D from STMicroelectronics is a quad JFET-input operational amplifier optimized for high-speed, low-power analog signal conditioning in industrial and instrumentation systems. It delivers 16 V/µs slew rate, ±11 V common-mode input range (up to V_CC), 2.5–4 MHz gain-bandwidth product, and 10¹² Ω input resistance - enabling precision DC-coupled amplification and wideband AC applications at 0°C to +70°C operating temperature.

For engineers reviewing the LF347D datasheet, LF347D pinout, LF347D application, or LF347D equivalent, key selection criteria include input bias current (≤20 pA typ), output short-circuit protection, latch-up free operation, and SO-14 package compatibility with space-constrained PCB layouts requiring four independent high-impedance amplifiers.

Technical Context

The LF347D integrates four matched JFET-input amplifier cells on a single monolithic die, combining high-voltage JFETs for ultra-low input bias current with bipolar transistors for robust output drive and internal frequency compensation. Each channel operates independently with rail-to-rail input common-mode range up to the positive supply rail.

It features unity-gain-stable architecture with 45° phase margin, 120 dB channel separation at Av = 100, and differential input voltage tolerance of ±30 V - supporting high-fidelity signal routing in multi-channel audio distribution, active filter cascades, and sensor front-end buffering without crosstalk or instability.

Key Specifications

Parameter	Value and Actual Design Meaning
Slew Rate	16 V/µs typical - enables faithful reproduction of fast transients in audio and pulse-amplification circuits without slew-induced distortion.
Gain-Bandwidth Product	2.5–4 MHz - supports stable closed-loop gain ≥10 at 100 kHz, suitable for active bandpass filters and wideband instrumentation.
Input Bias Current	20 pA typical at 25°C - minimizes offset drift in high-impedance sensor interfaces (e.g., piezoelectric or pH electrode amplifiers).
Input Common-Mode Range	±11 V (with ±15 V supply) - allows direct interfacing to signals near V_CC or ground without level-shifting circuitry.
Output Short-Circuit Duration	Infinite - permits safe operation under sustained fault conditions without device degradation or thermal shutdown.
Input Resistance	10¹² Ω - preserves signal integrity in megohm-source applications like photodiode transimpedance stages.
THD @ 1 kHz	0.01% at 2 V_pp, R_L = 2 kΩ - meets fidelity requirements for professional audio distribution and test equipment signal paths.

Pinout & Package

LF347D is housed in a 14-pin plastic small-outline (SO-14) package per JEDEC MS-012, with 1.27 mm pitch, 8.55–8.75 mm body width, and 5.8–6.2 mm body length. Pin 1 is marked by a beveled corner or notch.

Pin/Terminal	Circuit Role	Design Meaning
1	Inverting Input (Amp 1)	High-impedance differential input node for first op-amp channel; accepts negative feedback for inverting configurations.
2	Non-inverting Input (Amp 1)	High-impedance differential input node for first op-amp channel; used in non-inverting, voltage-follower, or comparator modes.
3	Output (Amp 1)	Class-AB buffered output capable of ±12 V swing into 2 kΩ load; includes short-circuit protection.
4	V_CC– (Negative Supply)	Ground reference for dual-supply operation; must be connected to system negative rail or ground in single-supply use.
5	Inverting Input (Amp 2)	Independent input for second amplifier; electrically isolated from other channels with >120 dB separation.
6	Non-inverting Input (Amp 2)	Second channel non-inverting input; supports DC-coupled buffer or precision summing applications.
7	Output (Amp 2)	Second independent output; shares same electrical specs as Pin 3 but isolated for multi-channel signal processing.
8	V_CC+ (Positive Supply)	Positive supply rail connection; supports ±15 V max or +30 V single-supply operation with appropriate common-mode limits.
9	Inverting Input (Amp 3)	Third channel inverting input; identical performance to Pins 1 and 5; enables triple-stage active filtering.
10	Non-inverting Input (Amp 3)	Third channel non-inverting input; usable for reference voltage buffering or multi-sensor signal conditioning.
11	Output (Amp 3)	Third independent output; rated for same output swing and load drive capability as other outputs.
12	Inverting Input (Amp 4)	Fourth channel inverting input; completes quad functionality for applications like 4-channel audio distribution or multi-axis sensor arrays.
13	Non-inverting Input (Amp 4)	Fourth channel non-inverting input; supports simultaneous high-Z sensing across four independent signal paths.
14	Output (Amp 4)	Fourth output; fully specified for same AC/DC performance, including 16 V/µs slew and 2.5 MHz GBW.

Key Features

Feature	Design Value
JFET input stage	Enables 20 pA input bias current and 10¹² Ω input resistance - critical for high-impedance sensor front-ends and electrometer-grade circuits.
Internal frequency compensation	Guarantees unity-gain stability without external components - simplifies design of voltage followers and gain-of-10 amplifiers.
Output short-circuit protection	Allows indefinite output grounding or rail-to-rail shorts without damage - essential for rugged industrial control I/O modules.
Latch-up free operation	Prevents destructive parasitic thyristor conduction during overvoltage or ESD events - improves reliability in noisy environments.
Wide common-mode range (±11 V)	Supports direct interface to signals referenced to V_CC or ground without level shifters - reduces component count in mixed-supply systems.

Applications

Audio Distribution Amplifier

Active Bandpass Filter Cascade

Use Scenario: Distributing a single line-level audio source to four independent outputs with minimal crosstalk and distortion.

IC Role / Device Role / Timing Role: Quad op-amp configured as unity-gain buffers, each driving a separate output path with >120 dB channel isolation.

Use Value: Maintains 0.01% THD at 1 kHz and preserves transient response via 16 V/µs slew rate - ensuring studio-grade signal integrity across all four channels.

Use Scenario: Implementing a 4-pole bandpass filter for 100 kHz signal extraction in RF receiver front-ends.

IC Role / Device Role / Timing Role: Four LF347D amplifiers cascaded in second-order sections, leveraging 4 MHz GBW and 45° phase margin for stable Q = 69 response.

Use Value: Achieves precise center frequency and high selectivity without external compensation - eliminating tuning complexity in production test equipment.

Multi-Sensor Signal Conditioning

Industrial Voltage Follower Array

Use Scenario: Simultaneously conditioning outputs from four high-impedance sensors (e.g., thermocouples, strain gauges) in PLC analog input modules.

IC Role / Device Role / Timing Role: Each amplifier used in non-inverting configuration with 10¹² Ω input impedance to prevent loading of mV-level sensor sources.

Use Value: Delivers <10 µV/°C offset drift and 20 pA bias current - enabling sub-0.1% measurement accuracy over 0°C to +70°C industrial temperature range.

Use Scenario: Providing isolated, low-output-impedance buffering for four independent reference voltages in precision DAC output stages.

IC Role / Device Role / Timing Role: Quad voltage follower with rail-to-rail input common-mode range (±11 V) accepting references from diverse supply domains.

Use Value: Eliminates need for discrete buffer ICs or level-shifters - reducing BOM count and PCB area in compact industrial DAC boards.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
TLC27M4CDR	Lower slew rate (3.6 V/µs), wider temp range (–40°C to +85°C), higher input offset voltage (10 mV max).	Better suited for low-speed, battery-powered instrumentation where power (<1.2 mA per amp) outweighs speed.	Select when supply current budget is <1.5 mA/amp and full-rail input common-mode is not required.
TL084CDR	Higher slew rate (13 V/µs), same SO-14 package, but no guaranteed output short-circuit protection or latch-up immunity.	Acceptable for lab-grade signal chains where fault tolerance is secondary to bandwidth.	Choose only if absolute short-circuit survivability is not mandated by safety or reliability standards.

Compared with TLC27M4CDR and TL084CDR, the LF347D uniquely combines infinite short-circuit duration, latch-up immunity, and 16 V/µs slew rate in a cost-optimized SO-14 package - making it the preferred choice for industrial analog I/O modules requiring both robustness and wideband fidelity.

Availability

LF347D is available at Aetrix Electronics and suitable for industrial analog I/O modules, precision sensor signal conditioning, multi-channel audio distribution, and active filter designs requiring stable component supply across extended production cycles.

Supply support for LF347D 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, microcontroller, and automotive ICs with vertical manufacturing and broad industrial certification coverage.

The LF347D belongs to ST's legacy precision analog op-amp family, designed specifically for cost-sensitive industrial and instrumentation applications demanding JFET-input performance, robustness, and long-term supply stability.

FAQ

Is LF347D pin-compatible with LF347N (DIP-14) and LF347DT (SO-14 tape-and-reel)?

Yes - LF347D uses the same SO-14 footprint and pinout as LF347DT, while LF347N shares identical electrical specifications and pin assignment in DIP-14 packaging. All three variants are functionally interchangeable in layout, though thermal and mechanical mounting differ.

Can LF347D operate from a single +30 V supply?

Yes - the absolute maximum supply rating is ±18 V (36 V total), so a +30 V single supply with ground reference is within specification. However, the input common-mode range extends only to V_CC– + 11 V and V_CC+ – 11 V, limiting usable input range to +11 V to +19 V in this configuration.

What is the minimum recommended load resistance for full output swing?

For ±12 V peak-to-peak swing at 25°C, ST specifies R_L ≥ 2 kΩ. Driving lower loads (e.g., 600 Ω) reduces output voltage swing and increases distortion; sustained operation below 2 kΩ may exceed thermal limits without heatsinking.

Does LF347D require external compensation capacitors?

No - LF347D is internally compensated for unity-gain stability. External capacitors are unnecessary for standard inverting/non-inverting configurations. Only specialized high-Q filter topologies or capacitive-load driving (>100 pF) may benefit from small series output resistors per ST application notes.

LF347D Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 14-SOIC (0.154", 3.90mm Width)

Packaging:: Tube

Product Status:: Active

Amplifier Type:: J-FET

Number of Circuits:: 4

Output Type:: -

Slew Rate:: 16V/µs

Gain Bandwidth Product:: 3 MHz

-3db Bandwidth:: -

Current - Input Bias:: 20 pA

Voltage - Input Offset:: 3 mV

Current - Supply:: 1.4mA (x4 Channels)

Current - Output / Channel:: 40 mA

Voltage - Supply Span (Min):: 44 V

Voltage - Supply Span (Max):: 44 V

Operating Temperature:: 0°C ~ 70°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 14-SO

LF347D FAQ

1.How can I place an order for LF347D through Aetrix?

Please submit a Request for Quotation (RFQ) for LF347D on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LF347D reliable?

The price and inventory of LF347D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LF347D is usually 5 days.

3.What payment methods are accepted for LF347D?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LF347D transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LF347D?

LF347D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LF347D order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LF347D?

For technical support, including LF347D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LF347D requirements.

6.How does Aetrix verify that LF347D is sourced from the original manufacturer or authorized distributors?

All LF347D products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LF347D meets industry standards.

7.What is the process for return or replacement of LF347D?

All LF347D units undergo pre-shipment inspection (PSI). If there is an issue with LF347D, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LF347D part is unused and in its original packaging.

Return procedure for LF347D:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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