What is LM358 Dual Op-Amp IC? Pin Diagram, Circuit, Applications
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The LM358 is a low power dual operational amplifier containing two independent high-gain amplifiers in a single package. It operates from a single or dual power supply and is widely used in signal conditioning, sensor interfacing, voltage comparators, active filters, audio circuits, and instrumentation. This app. note explains the LM358 pin diagram, internal circuit, working principle, specifications, features, and applications.
Key features of LM358
The LM358 is an industry standard, versatile IC containing two independent, high gain, internally frequency compensated operational amplifiers.
- Supply Range: Can operate on a single supply (3V to 32V) or dual supplies (+/- 1.5V to +/- 16V).
- Low Power: Draws very low supply current (approx. 500µA) regardless of the supply voltage.
- Wide Input Common Mode Range: Includes ground, allowing direct sensing near GND.
- Large DC Voltage Gain: approx. 100 dB.
- Bandwidth: 1MHz unity gain bandwidth (temperature compensated).
LM358 Pin Diagram
LM358 (Low Power Dual Operational Amplifier)
| Pin # | Pin Name | Description |
|---|---|---|
| 1 | OUTPUT 1 | Channel 1 Output |
| 2 | INVERTING INPUT 1 | Channel 1 Inverting Input |
| 3 | NON-INVERTING INPUT 1 | Channel 1 Non-inverting Input |
| 4 | GND | Ground |
| 5 | NON-INVERTING INPUT 2 | Channel 2 Non-inverting Input |
| 6 | INVERTING INPUT 2 | Channel 2 Inverting Input |
| 7 | OUTPUT 2 | Channel 2 Output |
| 8 | V+ | Chip Supply Voltage |
Example Use Case
Analog Sensor Signal Conditioning: If you have an analog temperature sensor that outputs a very small voltage (e.g., 0 to 0.5V), you can use one of the LM358’s op-amps configured as a non-inverting amplifier with a gain of 10. This boosts the sensor’s signal to 0 to 5V, perfectly matching the ADC (Analog to Digital Converter) range of a microcontroller like an Arduino for precise temperature readings.
Applications of LM358
Transducer amplification, DC gain blocks, active filters (e.g., bandpass filters), and LED drivers.
Summary
The LM358 combines two operational amplifiers in one IC for analog signal processing. It is widely used because of its low power consumption, wide operating voltage range, and versatile applications.