Why the LM358 is a Popular Choice in Low-Power Amplification: A Technical Overview

The LM358 is a versatile and popular solution that is used in cases where the requirements are not strict especially in terms of high power consumption, non-standard supply voltages and high speed. It features a straightforward switching circuitry that is ideal for most devices available. This also allows it to offer low costs as well as the removal of extra frequency compensation components.

It is also designed to operate on a supply voltage which is up to 32V and this is with a corresponding low current consumption. The LM358 is a popular choice that is used for many electronic projects especially those that require operational amplifiers. In this comprehensive guide you will learn about the LM358 and why it is the ideal choice for low power amplification. You will also learn about its equivalents, pinouts, and datasheet. Continue reading for more. 

What is the LM358?

It is an operational amplifier that offers a low power dual operational amplifier. The amplifier is made of two internally frequency compensated and independent high gain operational amplifiers. The LM358 is designed to be used for a wide range of applications particularly for single supply voltages and dual supply operations. A key thing to note is that when operating conditions are ideal the supply current is independent of the supply voltage. 

Another thing to note about the LM358 is that it features an extended input voltage range to ground/VEE and a low power consumption, both of which are ideal for dual supply and single supply operations. Unlike conventional operational amplifiers that are used for single supply applications the LM358 is better suited for diverse applications because of the numerous advantages it offers. 

This amplifier can be used for operation within supply voltages ranging from 3 to 32V. The common mode input ranges feature the negative supply that removes the need for external components that causes bias in different applications. Another thing worth noting is that the output voltage range also features a negative supply voltage. 

Working Operation of the LM358

Pin 8 in the LM358 plays a key role because it is the main power supply input and can be used as a comparator to handle different input voltage ranges. However it’s worth noting that when it is used as an operational amplifier it is important that the ranges are maintained between ±1.5V to ±16V.

There are two operational amplifiers present in the LM358. One of the amplifiers is designed to receive signals coming from pin 1 through pin 2 and 3. The second amplifier is designed to accept this signal through pins 5 and 6 and the output is then presented at pin 7.

For signal comparison one input can be connected to pin 2 and the other to pin 3. The voltage at pin 3 is then compared against the voltage at pin 2. A similar comparison occurs between the voltage at pin 6 and pin 5 resulting in two separate outputs which are output A and output B.

When the voltage at the non-inverting input A(+) on pin 3 exceeds the inverting input A(-) on pin 2, Amplifier A outputs a high signal. The same logic applies to Amplifier B: if the voltage at the non-inverting input B(+) on pin 5 is greater than that at the inverting input B(-) on pin 6, the output will be high.

Conversely, if the voltage at the non-inverting input A(+) on pin 3 is lower than the inverting input A(-) on pin 2, Amplifier A will produce a low output. Likewise, when the voltage at the non-inverting input B(+) on pin 5 is lower than at pin 6, Amplifier B’s output will switch to a low state.

It’s important to note that the LM358 can operate without requiring additional pull-up resistors for its output.

LM358 Application Circuit

Here are some fundamental applications to note: 

Dark Sensor Circuit Based on LM358 IC

The dark sensor circuit using the LM358 IC is designed to test photoresistors, phototransistors and photodiodes. For this you can replace the LDR with a phototransistor or photodiode. The components needed for the construction of this circuit include the LM358 IC, LDR, a 9V battery, resistors R1 (330Ω), R2 (1KΩ), R3 (10KΩ), a variable resistor VR1 (10KΩ) and a transistor Q1 (C547).

Impact Alarm Circuit Based on LM358 IC

Vibration alarm circuits are commonly used in homes and cars particularly in car anti-theft systems. It utilizes a piezoelectric sensor which should be attached to the door you want to secure. In this setup the LM358 operates as an inverting Schmitt trigger. The circuit’s threshold voltage can be adjusted using port 1 while resistor R1 serves as a feedback resistor.

Other Applications of LM358

• Controllers
• Various types of inverters
• Refrigeration units, washing machines and dishwashers
• Uninterruptible power supplies. 
• Engine control circuits
• Bridge current amplifiers
• Symmetrical amplifiers
• Home appliances
• Motherboards
• Split systems for indoor and outdoor use
• Power suppliers and chargers
• Pulse and oscillating generators. 

Basically the LM358 is a versatile solution and this is evident from the numerous applications it offers. 

Key Features of the LM358

The key features of the LM358 include the following: 

• Low input bias current
• Low power consumption current which makes it ideal for battery-powered applications.
• Internal frequency compensation
• Wide power supply range
• Unity gains bandwidth.
• Low input offset voltage and current. 
• Large output voltage. 
• Wide common mode input voltage range which includes ground.

Conclusion

The LM358 stands out as a highly versatile and widely used operational amplifier, particularly suited for low-power applications. Its ability to operate within a broad supply voltage range, coupled with low current consumption makes it an ideal choice for a variety of electronic projects. The LM358's straightforward design including internal frequency compensation and low input bias current further enhances its appeal by simplifying circuit design and reducing costs.

Throughout this overview we've explored the LM358's key features, its operation and its wide range of applications. From dark sensors and vibration alarms to controllers and power supplies. The LM358’s robustness and adaptability make it a reliable component in both simple and complex circuits ensuring consistent performance across a diverse array of devices. Whether you’re working on home appliances, automotive systems or general electronic projects the LM358 is a solid choice for low power amplification needs.

Download the datasheet here: LM358