LF351 IC : Pin Configuration, Circuit Working and Applications

Basically, the LF 351 op-amp is JFET- Junction Field Effect Transistor. This op-amp has a very high-speed input, and it is the most commonly available IC in the market because of its features like low cost as well as good act characteristics. This IC gives a high gain bandwidth result although it requires a very low-current supply. This operational amplifier will combine two states of the analog technologies on an only monolithic IC (integrated circuit). The JFET technology offers ample bandwidths; i/p offset currents, quick slew rates by low-input bias currents, & supply currents. This article discusses an overview of LF351 Op-Amp.

What is an LF351 Op-Amp?

The LF351 op-amp is basically a JFET input IC. It is a low-cost integrated circuit and gives high-performance characteristics. This IC gives high slew rates & high gain-bandwidth product even by working with a low power supply. Additionally, it has internally compensated i/p off-set voltage, high i/p impedance, little current supply, rapid settling time, and less harmonic distortion. The application of this IC mainly includes S&H(sample and hold) circuits, DAC’s (digital to analog converters), speed integrators, etc.

LF351 Op-Amp Pin Configuration

The pin configuration of LF351 and every pin is discussed below.

LF 351 IC Pin Configuration
LF 351 IC Pin Configuration
  • Pin1 (Offset Null 1): This Pin is used to eliminate the offset voltage & balance i/p voltage.
  • Pin2 (Inverting i/p): Inverting signal Input
  • Pin3 (Non-inverting i/p): Non-inverting signal Input
  • Pin4 (VEE): GND (-Ve Supply i/p )
  • Pin5 (Offset Null 2): This Pin is used to eliminate the offset voltage & balance i/p voltage.
  • Pin6 (Output): O/p of the operational amplifier
  • Pin7 (VCC): +Ve Supply Input
  • Pin8 (NC): Not linked

LF351 Op-Amp Features

The main features of LF351 Op-Amp include the following.

  • Low-power utilization
  • Safety of o/p short-circuit
  • Slew rate is high-16 V/us
  • Low offset current & input-bias
  • Latch-up free Process
  • Compensation of Interior Frequency

LF351 Op-Amp Specifications

The LF351 Op-Amp Specifications include the following.

  • A voltage supply is ±18V
  • Differential i/p voltage: ±30V
  • Range of i/p supply is ±15V
  • Lead temperature is260℃
  • Junction temperature is115℃
  • I/p Offset Voltage is 5mV
  • Power dissipation is 670mW

Equivalent LF351 Op-amps

The equivalent LF351 ICs are mainly IC LM301, IC CA3140, IC TLC271, IC TLC071, ICL7611, IC TLC081, and IC NTE857M.

Where to Use IC LF351?

The IC LF351 is a single op-amp, and the applications of IC LF351 involves in different application circuits that require high-speed integrators, high-input impedance, fast DACs (digital to analog converters), & sample & hold circuits, etc.

How to Use the LF351 IC?

The LF351 IC can be used to build sensitive overload sensor circuit. By connecting a sense resistor in the current lane, then the flow of current can be calculated in a circuit. If the resistance is high, then the measurement will be more accurate. But, the main disadvantage of high resistance is that it will change the function of the circuit where the measurement can be done. If an active type of sensor is utilized, then the sense resistance can be kept little. The following circuit diagram illustrates how this circuit can be built with a sense resistor & LF351 IC in the current lane. A voltage difference can be generated among the inverting as well as non-inverting terminals of the operational amplifier using a diode. Generally, the voltage drop across the diode in the circuit will be 0.2-0.3 V.

LF 351 Circuit Diagram
LF 351 Circuit Diagram

The value of the voltage drop can be influenced a bit with resistor R1, which will affect the flow of current through the D1 diode. If the resistor value is larger, the voltage drop across the diode will be smaller. The op-amp’s inverting input can be connected to the +ve supply voltage to the Rs (sense resistor). As a result, the op-amp’s voltage level at the output will be equivalent to the –ve supply voltage (–5 V). As the flow of current supplies through the Rs sense resistor increases, then the op-amp’s inverting i/o voltage can be decreased.

So the voltage drop across the resistor will become somewhat larger than the diode’s voltage drops, then the op-amp’s output will push button to the +ve voltage supply level. A relay otherwise an indicator lamp can be attached to the output of the IC. The utmost voltage supply for the IC can be ±15 V, thus this circuit can be applied for monitoring the symmetric power supplies with the voltages among 5V & 15V.

Maximum Ratings of IC LF351

The maximum ratings of this IC are listed in the following tabular form.



Supply Voltage (VCC)

±18 V
Differential Input Voltage (VI(DIFF))

30 V

Input Voltage Range (VI) ±15 V
Output Short Circuit Duration Continuous
Power Dissipation (PD) 500 mW
Operating Temperature (TOPR) 0 ~ +70 °C
Storage Temperature Range (TSTG)                                   -65 ~ +150 °C

Applications of LF351 Op-Amp

The applications of LF351 Op-Amp include the following.

  • Square wave oscillator
  • High-speed integrators
  • High Q-notch filter
  • DACs (Digital-to-Analog-Converters)
  • Sample & Hold Circuit

Thus, this is all about IC LF351 data sheet. These are low-cost op-amps, and this can merge two modern technologies on a monolithic IC (integrated circuit). This JFET technology offers an extensive bandwidth as well as quick slew-rates by little input bias, offset and supply currents. Here is a question for you, what is the main function of IC LF351 Op-Amp?

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