The LM358 is an operational amplifier (op-amp) made by multiple manufacturers, including Texas Instruments, ON Semiconductor, and STMicroelectronics, among others. It is a dual operational amplifier, meaning it contains two independent op-amps in one package. Below is a detailed explanation of the LM358 pin functions, pin specifications, circuit principle, packaging, and frequently asked questions (FAQs).
LM358 Pin Function and Specifications
LM358 comes in several common packages, such as 8-pin dual in-line package (DIP-8), surface-mount packages like SOIC-8, and others. For the purpose of this explanation, we will focus on the DIP-8 package.
LM358 Pin Configuration (DIP-8)The LM358 has a total of 8 pins. Below is a detailed explanation of each pin:
Pin Number Pin Name Pin Function Pin 1 Output A This is the output pin for the first op-amp (Op-Amp A). It provides the amplified output signal based on the input signals connected to the non-inverting (+) and inverting (-) inputs. Pin 2 Inverting Input A This is the inverting input of the first op-amp (Op-Amp A). A voltage applied here will be inverted and amplified to the output pin (Pin 1). Pin 3 Non-inverting Input A This is the non-inverting input of the first op-amp (Op-Amp A). A voltage applied here will be amplified without inversion. Pin 4 V- (Negative Supply Voltage) This is the negative supply pin for the entire IC. It connects to the negative voltage rail (often ground in single-supply configurations). Pin 5 Non-inverting Input B This is the non-inverting input of the second op-amp (Op-Amp B). Similar to Pin 3, a voltage applied here is amplified without inversion. Pin 6 Inverting Input B This is the inverting input of the second op-amp (Op-Amp B). A voltage applied here will be inverted and amplified to the output pin (Pin 7). Pin 7 Output B This is the output pin for the second op-amp (Op-Amp B). It provides the amplified output signal for the second op-amp based on the input signals applied to the non-inverting (+) and inverting (-) inputs. Pin 8 V+ (Positive Supply Voltage) This is the positive supply pin for the entire IC. It connects to the positive voltage rail.LM358 Packaging
As mentioned, the most common package for LM358 is the DIP-8 (Dual In-line Package) with 8 pins. It is also available in surface-mount packages such as SOIC-8 (Small Outline Integrated Circuit) and others like TSSOP-8.
LM358 Pin Function Details (DIP-8 Package)
Let’s go into a bit more detail on the role of each pin in the context of operational amplifier circuits:
Pin 1: Output A The output pin for Op-Amp A. The voltage here depends on the difference between the non-inverting input (Pin 3) and the inverting input (Pin 2). It is the pin through which the amplified signal is delivered to the next stage of the circuit. Pin 2: Inverting Input A The voltage applied here is inverted and amplified. When connected to a feedback network, it controls the gain of the op-amp. For negative feedback, it helps stabilize the output by adjusting the amplification. Pin 3: Non-inverting Input A The voltage applied here is amplified in the same polarity. This is typically where a signal is input if a non-inverting amplifier configuration is used. Pin 4: V- (Negative Supply) The negative power supply pin, which in most cases connects to ground in a single-supply configuration. Pin 5: Non-inverting Input B Similar to Pin 3, this is the non-inverting input for the second op-amp. It also allows the input signal to be amplified in the same polarity. Pin 6: Inverting Input B The inverting input of the second op-amp. When a signal is applied here, it is inverted and amplified. Pin 7: Output B The output of the second op-amp. It provides the amplified signal based on the inputs applied to Pins 5 and 6. Pin 8: V+ (Positive Supply) The positive power supply pin, typically connected to a positive voltage rail.Frequently Asked Questions (FAQs) about LM358
Q1: What is the function of the LM358? A1: The LM358 is a dual operational amplifier IC used for signal amplification, filtering, and other analog processing tasks. It contains two independent op-amps in one package.
Q2: What is the supply voltage range for the LM358? A2: The LM358 can operate with a single power supply in the range of +3V to +32V, or with dual power supplies of ±1.5V to ±16V.
Q3: What is the typical application for the LM358? A3: Typical applications include signal amplification, active filters , audio amplification, and voltage followers, among others.
Q4: Can the LM358 be used with a single supply voltage? A4: Yes, the LM358 can be used with a single supply voltage, which makes it versatile for many low-power applications.
Q5: What are the input voltage ranges for the LM358? A5: The input voltage range for the LM358 is typically from 0V to (V+ – 1.5V), where V+ is the positive supply voltage.
Q6: What is the output voltage range of the LM358? A6: The output voltage typically ranges from 0V to (V+ – 1.5V) when powered by a single supply. In dual-supply configurations, it can range from (V-) to (V+).
Q7: How is the gain of the LM358 determined? A7: The gain of the LM358 is determined by the feedback network connected between the output and input pins, according to the configuration (inverting, non-inverting, or differential).
Q8: Can the LM358 be used in differential amplifier configurations? A8: Yes, the LM358 is commonly used in differential amplifier configurations where it amplifies the difference between two input signals.
Q9: What is the bandwidth of the LM358? A9: The typical bandwidth of the LM358 is around 1 MHz at a gain of 1.
Q10: What is the power consumption of the LM358? A10: The LM358 consumes very little power, with typical supply currents around 1 mA per op-amp when operating at a single supply.
Q11: Is the LM358 suitable for high-speed applications? A11: The LM358 is not designed for high-speed applications. It has a low slew rate (0.3V/µs), so it is best suited for low-frequency signal processing.
Q12: Can the LM358 drive capacitive loads? A12: The LM358 can drive moderate capacitive loads, but stability may degrade when driving highly capacitive loads.
Q13: How does the LM358 perform at low voltages? A13: The LM358 performs well at low voltages, especially in single-supply configurations, making it suitable for battery-operated devices.
Q14: What are the common failure modes of the LM358? A14: Common failure modes include input/output voltage exceeding supply limits, excessive temperature rise, and improper power supply configurations.
Q15: What is the internal architecture of the LM358? A15: The LM358 consists of two independent op-amps with internal transistor s and resistors configured for voltage amplification.
Q16: What is the difference between LM358 and LM324 ? A16: The LM358 has two op-amps, whereas the LM324 contains four op-amps in a single package. Both are similar in function but have different package configurations.
Q17: Can the LM358 be used in audio applications? A17: Yes, the LM358 is often used in low-frequency audio applications, including pre-amplifiers and filters.
Q18: Is the LM358 suitable for use in automotive circuits? A18: Yes, the LM358 can be used in automotive circuits, provided it operates within the recommended voltage and temperature ranges.
Q19: What is the maximum output current of the LM358? A19: The LM358 can typically source or sink 20 mA of output current, but this can vary based on the load and operating conditions.
Q20: What is the recommended operating temperature range for the LM358? A20: The recommended operating temperature range is -40°C to +85°C.
This provides a comprehensive overview of the LM358 pin functions, packaging, and frequently asked questions. Let me know if you'd like to explore anything else related to the LM358!