LF356N datasheet, pinout & balance

Electronics: Photodiode amplification works with LM258N but doesn’t with LF356N

LF356N JFET Input Operational Amplifier

The LF356N is a single-channel operational amplifier produced by Texas Instruments, widely used in analog circuit designs. The standout features of this chip include its high speed, low noise, and JFET input design (junction field-effect transistor input), which results in an exceptionally high input impedance.

In terms of specific technical parameters, the LF356N offers a bandwidth of approximately 5 MHz, making it ideal for high-speed analog circuits. Additionally, it has a solid slew rate of around 12 V/µs, enabling it to quickly respond to rapidly changing signals.

Another great advantage of the LF356N is its extremely low input bias current—typically about 30 pA—which is perfect for dealing with high-impedance signal sources. Moreover, its input voltage noise density is very low (about 12 nV/√Hz at 1 kHz), effectively enhancing the accuracy and quality of the signal.

Regarding power supply requirements, the LF356N can operate with dual power supplies ranging from ±5V to ±18V, providing greater flexibility in circuit design. Its output voltage swing is close to the supply voltage range, allowing for maximum use of the available power supply.

LF356N Pinout

LF356N Equivalent

LF356N Equivalent Pinout

Notes on Selecting Equivalent Models:

• If your application demands high speed and wider bandwidth, consider using LF357N or OPA134, as both offer superior bandwidth and slew rate compared to LF356N, especially LF357N.
• For applications requiring extremely low input bias current and lower noise, the OPA134 is preferable due to its significantly better noise and bias characteristics.
• If budget-conscious designs with moderate performance requirements (bandwidth, slew rate) are needed, TL071 or TL081 provide economical yet closely matched performance.

LF356N Precision Analog Circuit Design

The input signal passes through a resistor (2 kΩ) into the inverting input (pin 2) of the operational amplifier. The output (pin 6) connects back to the inverting input (pin 2) through a feedback resistor (2 kΩ), forming a negative feedback structure that stabilizes the gain. Additionally, a 2N4416 JFET transistor, along with a 3 kΩ resistor, is connected between the output terminal and ground to achieve voltage limiting or clamping functionality at the output.

LF356N Signal Conditioning Applications

LF356N is a JFET-input operational amplifier chip that’s commonly used for conditioning various analog signals. It offers an exceptionally high input impedance, low noise, and fast response speed, making it ideal for handling sensitive or delicate signals.

Specifically, the LF356N is frequently used in these scenarios:

Voltage Buffer (Voltage Follower)
When your signal source is sensitive or fragile and can’t handle much load, using the LF356N as a buffer works especially well. It hardly draws any current from the source, being very gentle and preserving the integrity of the original signal.

High-Impedance Amplifier Circuits
Certain specialized sensors—like piezoelectric or photo-sensitive sensors—require amplifiers with extremely high input impedance. The LF356N excels here, with input impedances in the mega-ohms range, easily handling weak and sensitive signals.

Precision Integrator Circuits
For circuits that require accurate integration, such as signal accumulation or integral control circuits, the LF356N provides rapid response, ensuring precise signal processing without distortion or delay.

LF356N Alternative to TL071 Op-Amp