Introduction to LM358 IC

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As far as we are aware, 555 timers, single logic gates, microcontrollers, microprocessors, voltage regulators, and op-amps are all available in a variety of configurations. These ICs include the LM741, LM7805, LM35, LM324 IC, LM337 IC, LM338 IC, LM339 IC, LM1117, and many others.

The most common integrated circuit (IC) in electronic sensors and many other circuits is the LM358, and you will learn how to use it in different DIY electronics projects blog.

LM358 Overview

LM358 is a dual op-amp IC integrated with two op-amps powered by a common power supply. It can be considered as one-half of LM324 Quad op-amp which contains four op-amps with a common power supply. The differential input voltage range can be equal to the power supply voltage. The default input offset voltage is very low, at a magnitude of 2mV. The typical supply current is 500uA, independent of the supply voltage range, with a maximum current of 700uA. The operating temperature ranges from 0˚C to 70˚C at ambient, whereas the maximum junction temperature can be up to 150˚C.

LM358 Features

– It consists of 2 OP-AMPs internally.

  • The output voltage swing is high.
  • The large DC voltage gain is around 100 dB.
  • Wider bandwidth of 1 MHz (temperature compensated).
  • The supply current drain is very low.
  • The wider power supply range, in the single power supply, is 3V to 32V, while the dual power supply range is ±1.5V to ±16V.
  • 2mV low input offset voltage.
  • Common mode input voltage range includes ground.
  • The differential input voltage range is similar to the power supply voltage.
  • Internally frequency compensated for unity gain.
  • Short circuit protected outputs.
  • Soldering pin temperatures up to 260°C.
  • Available in TO-99, SOIC, DSBGA, and CDIP packages.

LM358 Packages

The available package is TO-CAN, SOT-23(5), DSBGA, and PDIP. All of these packages along with their dimensions and part numbers are given below:

  • PDIP(8) – 9.81
  • DSBGA(8) – 1.31
  • TO-CAN(8) – 9.08
  • SOIC(8) – 4.90

LM358 Applications

LM358 Dual Op-Amp IC is widely used in many real-life applications. Some of the major applications of LM358 IC are listed below:

  • DC gain block
  • General signal conditioning
  • General signal amplification
  • Transducer amplifier
  • Operational amplifier circuit
  • Current loop transmitters for 4 to 20 mA
  • Active filters
  • Comparators (loop control & regulation)
  • Integrator, differentiator, adder, voltage follower, etc.

It can be used in real-life applications like shock alarm circuits and dark sensor circuits.

Application Examples

Operational Amplifier

A signal conditioner, DC amplifier, filter, and device for use with external feedback elements like capacitors and resistors between its output and input terminals are all examples of operational amplifiers or op-amps for short. Op-amps are DC-coupled high-gain voltage amplifying devices.

The op-amp can be employed as a differential amplifier, integrator, or summer depending on the feedback configuration it has—whether resistive, capacitive, or both.

LM358 as Comparator

In electronics, a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals, V+ and V-, and one binary digital output that is low when V- is greater and high when V+ is greater.

The LM358 comparator IC consists of two inbuilt operational amplifiers (Op-Amp), which means two comparators in a single IC.

To use LM358 as a comparator, we need to connect the power source with the Vcc and GND pin of the LM358 IC to activate the IC. Then, we need to provide two input voltages to the Op-Amp for comparison. Now, we can get an output from the Op-Amp.

To understand it more clearly, let’s see the working of circuits below. 

Digital Dark Sensor Using LM358

Working

The resistivity of the LDR, an electrical component, changes as light is shined onto it. When no light is incident on it, the LDR offers the highest resistance, generating a signal across the non-inverting terminal of the Op-amp that is used to turn on the LED when darkness is detected. When light is incident on it, the resistivity decreases, and when no light is incident on it, the LDR offers the highest resistance.

If the LED stays on even when no darkness is present, you can adjust the 10K potentiometer preset until the LED turns OFF to fine-tune the circuit’s sensitivity.

12V Battery Monitoring Circuit

The Battery Level Indicator Circuit uses the Dual Op-Amp IC LM358 to monitor the three essential levels of a battery: Low, Normal, and Full.

Working

The circuit keeps track of the 12V battery voltage and shows the battery’s charge state, with an LED lighting up to indicate low voltage, normal voltage, or full voltage. The red/yellow and yellow/green LEDs’ ON/OFF values are adjusted by the potentiometer. For instance, the green LED activates at 12V and the red LED at 11V. The yellow LED continues to glow when the battery voltage is between 11V and 12V. This circuit can be slightly adjusted to monitor voltages such as 4 volts, 6 volts, 24 volts, and others.

Two operational amplifiers are compensated internally. We can use both op-amps simultaneously, or just one if needed.

  • Two internally compensated op-amps.
  • Removes the necessity of dual supplies.
  • Power drains are suitable for battery operation.
  • Permits direct sensing close to GND and VOUT.
  • Compatibility with all forms of logic.

Frequently Asked Questions

Is LM358 a good op-amp?

Yes, it is designed to operate from a single power supply over a wide range of voltages from 3 to 32V. This makes it a popular general-purpose Op-Amp that is used in many projects since a negative power supply is not required as with most Op-Amps. This gives it a place in every hobbyist’s parts bin.

Why is LM358 used in IR sensors?

In IR sensors, the operational amplifier (op-amp) of LM358 is used as a comparator. When the IR receiver does not receive the signal, the potential at the inverting input goes higher than that at the non-inverting input of the comparator (LM358). Thus, the output of the comparator goes low and the LED does not glow.

Is LM358 a single supply?

Yes, it is designed for single-supply operation. This means that with a +12V supply, it could provide a 10.5 Vp-p output swing, which is higher than many other op-amps that might only allow a 2 Vp-p output swing for the same 12V supply.

Is LM358 unity gain stable?

Yes, LM358 family series op-amps are unity-gain stable and suitable for a wide range of general-purpose applications.

Does an LM358 need negative voltage?           

No, it does not. For the given circuit, it does not matter which signal is used (except fixed 0); it would always need a negative output from one of the OPs. The signal just decides which OP would need the negative voltage.

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