The Ultimate Guide to LM358 Dual Op-Amp vs LM393 Dual Comparator

Overview of LM358 and LM393 ICs

The LM358 and LM393 integrated circuits are often used in electronic systems for various analog functions. Here's an overview of each IC including their characteristics, functionalities, and typical applications.

LM358

Characteristics and Functionalities

• The LM358 IC is a dual operational amplifier (op-amp). It means that there is a pair of op-amps in a single IC package.
• It typically operates at a single power supply voltage but can also be operated from dual supplies. The supply voltage can range from 3 to 32V for a single supply and ±1.5 to ±16V for a dual supply setup.
• The quiescent current is low, thus it is suitable for battery-operated devices.
• It has a wide bandwidth which is temperature compensated.
• It features large DC voltage gain: about 100 dB.
• It has a common-mode input voltage range which includes ground, meaning that negative input signals can be dealt with in single supply operations.

Typical Applications

• LM358 ICs are used in transducer amplifiers, DC gain blocks, and all the conventional operational amplifier circuits.
• Because of their low power consumption, they are suitable for battery-powered devices.
• They are commonly used in control circuits, audio pre-amplifiers, simple analog to digital converters, and many other light analog signal processing tasks.

LM393

Characteristics and Functionalities

• The LM393 IC contains two independent voltage comparators, designed to operate from a single supply over a wide range of voltages.
• Similarly to the LM358, operation from dual supplies is also possible and the power supply range is wide: from 2V to 36V single supply or ±1V to ±18V dual supply.
• It is designed for specifically comparing two voltage levels; hence it outputs a digital signal (high or low) depending on which input is higher.
• The output stage has a transistor switch without pull-up resistor, needing an external pull-up for the output when used as a comparator.
• The LM393 has a lower input bias current than LM358.

Typical Applications

• The LM393 is ideally suited for driving logic circuits from analog signals.
• It is widely used for sensor signal processing, as it can determine when a certain threshold has been crossed.
• Popular in signal limit detection, voltage comparators in power tools and alarms, and various types of analog-digital interfaces.

Both the LM358 and LM393 are fundamental components in electronic design for analog signal processing and comparing, respectively. Their low cost, widespread availability, and supportive electrical characteristics make them a staple in many electronics toolboxes. When using them, it is crucial to check their data sheets for detailed specifications, pin configurations, and recommended operating conditions for successful circuit implementation.

LM393 Overview

The LM393 is a type of comparator IC that is widely used in many electronic applications due to its versatility and cost-effectiveness. Below is a detailed overview of the LM393.

General Characteristics:

• Type: The LM393 consists of two independent precision voltage comparators.
• Supply Voltage Range: It can operate from a single power supply over a wide range of voltages, typically from 2 to 36 volts for single supply, or ±1 to ±18 volts if a dual supply is used.
• Input Bias Current: It has a very low input bias current, making it suitable for precision applications.
• Offset Voltage: Typically the input offset voltage is low, which helps in maintaining accuracy in voltage comparison applications.
• Response Time: The LM393 features a fast response time, which makes it suitable for applications requiring quick decisions based on input voltage levels.
• Output: The output is an open-collector transistor. This means it needs an external pull-up resistor to supply the load current. In its off state, the output effectively becomes "open" and does not sink current.

Pin Configuration:

A typical LM393 IC has 8 pins with the following functions:

1. Output 1: The output of comparator 1.
2. Inverting Input 1: The inverting input of comparator 1.
3. Non-inverting Input 1: The non-inverting input of comparator 1.
4. Vcc: Positive supply voltage.
5. Non-inverting Input 2: The non-inverting input of comparator 2.
6. Inverting Input 2: The inverting input of comparator 2.
7. Output 2: The output of comparator 2.
8. GND (Vee): Ground or the negative supply voltage.

Functionality:

The primary function of the LM393 is to compare two voltages and provide a digital output to indicate which of the two is higher. You can set one input as a reference voltage and the other as a variable input. If the non-inverting (+) input is higher than the inverting (−) input, the output will be in a low state (close to the ground). If the inverting input is higher, the output will be high impedance.

Applications:

• Detection circuits: To detect whether a signal has crossed a certain threshold.
• Window comparators: To check if a voltage lies within a certain range.
• Zero-crossing detectors: To detect when a sinusoidal signal changes polarity.
• IR receivers: To process the output from IR photodiodes.
• Battery chargers: To monitor charging voltages.
• Motor control circuits: To detect overcurrent or other unsafe conditions.

The LM393 is appreciated for its reliability, easy usage, and capacity to function properly even under temperature changes and with minimal supply voltage variation. This makes it an excellent choice for both hobbyist projects and commercial products. Always consult the datasheet of the LM393 for the exact specifications and usage guidelines from the manufacturer for the best results in your specific application.

Specifications Comparison

When comparing the specifications of the LM358 operational amplifier and the LM393 comparator, it is important to recognize that while they may share some specifications, they are designed for different purposes. Here's a basic comparison of their typical specifications:

Power Supply:

• LM358: Single supply voltage ranges typically from 3V to 32V, or dual supplies of ±1.5V to ±16V.
• LM393: Can operate from a single supply voltage of 2V to 36V, or a dual supply of ±1V to ±18V.

Input Offset Voltage:

• LM358: Input offset voltage generally falls in the range of a few millivolts, around 2mV to 7mV.
• LM393: Input offset voltage is typically less than the LM358, and often below 2mV.

Input Bias Current:

• LM358: Has a higher input bias current, typically in the range of tens to hundreds of nanoamperes.
• LM393: Features much lower input bias current, often in the range of a few nanoamperes.

Quiescent Current:

• LM358: Uses comparatively more quiescent current than the LM393, but still low, typically a few hundred microamperes.
• LM393: Lower quiescent current, which may be very important for power-sensitive applications.

Response Time / Slew Rate:

• LM358: Generally has a slower slew rate than the LM393 because it is designed for linear applications where slower changes are expected.
• LM393: Since it is designed for fast switching applications, the response time of the LM393 is generally faster, with swift output transitions.

Output Configuration:

• LM358: Produces an analog output that is directly proportional to the voltage difference between the input terminals.
• LM393: The output is an open-collector digital signal that goes low or remains high impedance depending on the input voltages comparison.

Common Applications:

• LM358: Ideally suited for integrators, summing amplifiers, active filters, and general feedback applications.
• LM393: Primarily used in comparator applications, such as zero-crossing detectors, simple analog-to-digital converters, and voltage monitors.

Packaging:

Both the LM358 and LM393 come in various package types, including the common 8-pin DIP (Dual In-line Package) and SOIC (Small Outline Integrated Circuit).

These are general specifications and can vary slightly depending on the manufacturer and the particular variant of the IC. For specific projects or designs, it is crucial to refer to the datasheets provided by the manufacturer for the exact characteristics and limitations of the chips. Remember that electrical specifications such as temperature range, power dissipation, and input/output voltage ranges are also key considerations that should be matched to the needs of your circuit.

Features Comparison

When comparing the features of the LM358 operational amplifier and the LM393 comparator, we will be looking at the characteristics that define their functionality and typical applications. Here is a comparative overview:

LM358 Operational Amplifier:

• Dual Op-Amp: Contains two independent operational amplifiers in one package.
• Output Type: The output is able to swing close to the supply rails (ground and positive supply).
• Input Type: Both amplifiers have a common-mode voltage range that includes ground. This means they can handle input signals that go down to the ground level, which is particularly convenient for single-supply operations.
• Slew Rate: Moderate, which is sufficient for low-frequency signals (audio, DC signals).
• Phase Compensation: Internal frequency compensation is provided.
• Amplification: Designed to amplify continuous analog signals.
• Voltage Gain: Typically high open-loop voltage gain.
• Power Consumption: Generally low, but higher compared to comparators like the LM393.
• Stability: Stable over a wide range of operating conditions.

LM393 Comparator:

• Dual Comparators: Contains two independent voltage comparators in one package.
• Output Type: An open-collector output which allows the output to be pulled to any voltage level up to the maximum supply voltage (within the limits of the device) when used with an external pull-up resistor. This also allows for wired-AND logic configurations.
• Input Type: Designed to work with differing input voltages across a broad range.
• Response Time: Fast response suitable for rapidly changing signals or digital circuits.
• Voltage Comparison: Ideal for comparing voltages rather than amplifying them.
• Offset Voltage: Typically exhibits lower offset voltage than an operational amplifier.
• Voltage Gain: Not usually specified because comparators are not designed to operate in a linear mode; they are intended to saturate.
• Power Consumption: Lower than the LM358, which is especially beneficial in portable/battery operated applications.
• Hysteresis: Can be added externally to improve noise immunity and provide a clean, stable output transition.

Key Feature Comparisons:

• Purpose: LM358 is meant for analog signal processing operations where smooth voltage amplification is required, whereas LM393 is tailored for digital decision-making tasks where a fast and clear transition between output states is necessary.
• Output Drive Capability: LM358 can directly drive loads in some cases, while LM393 typically requires an external pull-up resistor due to its open-collector output.
• Response to Fast Signals: LM393 can handle rapid signal changes more effectively, making it preferable for fast switching applications.
• Supply Voltage Sensitivity: LM358 can operate closer to the ground (zero volts) which is beneficial in single power supply systems, though LM393 has a wider overall supply voltage range.
• Noise Performance: Generally, the LM393, being a comparator, is designed to reject noise better than an operational amplifier by means of external hysteresis.

In summary, the LM358 op-amp is a versatile chip for linear voltage processing applications, whereas the LM393 is geared more towards digital output applications where comparison of signals rather than amplification is required. The choice between the LM358 and LM393 would be determined by the specific needs of the application — whether the requirement is to amplify an analog signal with the LM358 or to switch digital outputs with the LM393.

Pinout Comparison

The LM358 and LM393 are both Dual Inline Package (DIP) ICs, which means their physical package is rectangular with pins on both sides, and are available in various packages like 8-DIP, 8-SOIC, etc. Let's have a look at their typical 8-pin configuration.

LM358 (Dual Operational Amplifier)

The pinout of the LM358 is as follows:

Pin 1 - Output 1: The output of the first op-amp.
Pin 2 - Inverting Input 1 (-): The inverting input of the first op-amp.
Pin 3 - Non-Inverting Input 1 (+): The non-inverting input of the first op-amp.
Pin 4 - Vcc- (GND): Negative supply voltage (usually Ground).
Pin 5 - Non-Inverting Input 2 (+): The non-inverting input of the second op-amp.
Pin 6 - Inverting Input 2 (-): The inverting input of the second op-amp.
Pin 7 -Output 2: The output of the second op-amp.
Pin 8 - Vcc+: Positive supply voltage.

LM393 (Dual Comparator)

The pinout of the LM393 is as follows:

Pin 1 - Output 1: The output of the first comparator.
Pin 2 - Inverting Input 1 (-): The inverting input of the first comparator.
Pin 3 - Non-Inverting Input 1 (+): The non-inverting input of the first comparator.
Pin 4 - Vcc- (GND): Negative supply voltage (usually Ground).
Pin 5 - Non-Inverting Input 2 (+): The non-inverting input of the second comparator.
Pin 6 - Inverting Input 2 (-): The inverting input of the second comparator.
Pin 7 - Output 2: The output of the second comparator.
Pin 8 - Vcc+: Positive supply voltage.

As you can see, both the LM358 and LM393 have similar pinouts in terms of what each pin does on each chip, with the primary difference being their functionality (operational amplifier vs comparator). This consistency can be helpful in design and troubleshooting, allowing for more straightforward substitutions and modifications. But remember to always consult the datasheet for the specific chip variant you are using, as package styles and pin assignments can sometimes vary.

Internal Circuitry Comparison

When comparing the LM358 and LM393, it's essential to consider the internal circuitry alongside the functionality of both IC units. These circuits are responsible for the operation of the different functionalities between the LM358 as an operational amplifier and the LM393 as a comparator.

Unfortunately, a detailed comparison pertaining only to the written form would be insufficient given the complex nature of the internal circuitry of these ICs. However, I can give you an idea about their internal architectures:

LM358

The LM358 consists of two independent, high-gain, internally frequency-compensated op-amps designed specifically to operate from a single power supply over a wide range of voltages. Key elements in the internal circuitry include:

• Input Transistors: High impedance differential input stage that accepts a wide range of input signals.
• Nulling Circuitry: Used for externally offsetting any DC errors.
• Signal Amplification Stages: Multiple transistor-based amplification stages, ensuring high voltage gain.
• Push-pull Output Stage: Capable of driving a variety of loads, this can output analog signals.

LM393

The LM393 consists of two independent voltage comparators that are designed to operate from a single power supply over a wide voltage range. Key elements in the internal circuitry include:

• Input Transistors: A differential input stage that supports comparison of different voltage levels.
• Emitter Stage & Voltage Amplification: The emitter of the transistor in the differential pair is connected to a current source. The voltage amplification stage is connected to this emitter stage.
• Level Translator & Open Collector Output Stage: Outputs a digital signal (high or low) depending on which input is higher.
• Output Stage: Opens the collector configuration to achieve a wired-OR functionality.

It's important to note that these are simply generic descriptions of general architecture found within both the LM358 and LM393. Precise details may vary by manufacturer and exact chip variants. For a complete understanding of the internal schematics and their specific components, it is always recommended to consult the datasheet provided by the manufacturer.

Applications Comparison

Given their different functionalities, the LM358 operational amplifier and the LM393 comparator naturally lend themselves to distinct types of applications. Let's go over some typical uses for each.

LM358 Operational Amplifier:

The LM358 is a two-channel op-amp, often used where signal amplification and processing are required. Some typical applications include:

• Summing Amplifiers: When used as a summing amplifier, the LM358 can amplify the sum of several voltages applied to its inputs.
• Integrators and Differentiators: The LM358 can be used in these types of circuits, often found in analog computing or waveform shaping applications.
• Active Filters: When used in combination with resistors and capacitors, the LM358 can create various types of signal filters.
• Signal Amplification: Can be used to amplify signals in various applications like audio preamplification, sensor signal amplification, etc.
• Voltage Followers (Buffer Amplifiers): This configuration is useful when you want to interface two circuits without loading the source or introducing signal degradation.

LM393 Comparator:

The LM393 is a dual independent precision voltage comparator capable of single or split supply operation. It's typically used where you need to compare two voltages and make a decision based on that comparison. Some common applications include:

• Zero-Crossing Detectors: In this application, one of the input terminals is connected to the ground, and an AC signal is applied to the other input terminal. The comparator then provides a square wave output each time the AC signal crosses zero.
• Relay Drivers: Comparator ICs can be used to drive relays when some specific conditions are met.
• Voltage Level Detectors: The LM393 can be used in voltage detection circuits when it is necessary to monitor and detect if a certain voltage threshold has been surpassed.
• Analog-to-Digital Converters (ADCs): The LM393 is used in ADCs as a basic building block.
• Peak Detectors: Comparators can be used to detect and hold the peak value of an input signal.

It's important to note that the breadth of applications for both the LM358 and LM393 is wide, and the above examples just scratch the surface. In both digital and analog electronics, these ICs are truly versatile and remain staple components in a vast array of circuits.

Equivalents Comparison

The LM358 is a dual operational amplifier and the LM393 is a dual comparator. It is important to mention that the equivalents I'm going to list, as good alternatives, serve similar functions or have similar characteristics, but their specifications may differ.

LM358 Operational Amplifier Equivalents:

• TL072: This is a low-noise JFET dual operational amplifier. It has similar characteristics to the LM358 but has a superior performance in terms of noise.
• NE5532: This is another high-quality dual op-amp which generally has superior performance characteristics to the LM358, including lower distortion and a higher slew rate.
• MCP602: The MCP602 is a dual op-amp from Microchip. It has a similar pin-out and is similar in performance to the LM358, but operates with a lower supply voltage.

LM393 Comparator Equivalents:

• TL331: This is a single comparator, but similar in many respects to the LM393 (just one comparator rather than two in the package). It's also capable of functioning effectively over a wide power supply range.
• LM339: This is a quad comparator IC. Each comparator in an LM339 functions in a similar way to an LM393, so this is a good choice if you need more than two comparifiers.
• LM311: This is a single comparator and is capable of running off higher voltages than the LM393. It also has strobe functionality.

In selecting an alternative, whether you need them to be exactly similar to the original IC terms of power requirements, output type, speed, and heating (for example) is all dependent on the project you are working on. Always refer to the manufacturer's datasheet for information about pin assignments, power ratings, and other specifications to make sure the device you're looking at would serve as a suitable replacement.

Package Comparison

Packaging types for the LM358 operational amplifier and the LM393 comparator vary, and thus the two chips can often be found in similar forms. The right package type depends on the specifics of the application, such as space constraints, mounting style, manufacturing techniques, and thermal considerations.

Here's a comparison of some packaging types for these two ICs:

LM358 Operational Amplifier Packages:

• DIP (Dual In-line Package): This is a common package for the LM358 and contains 8 pins. It is easy to handle and suitable for breadboard or through-hole PCB designs.
• SOIC (Small-Outline Integrated Circuit): This is a surface-mount package for the LM358 that also contains 8 pins. It is smaller than the DIP package and requires SMT (Surface Mount Technology) to mount the IC on the PCB.
• TSSOP (Thin Shrink Small Outline Package): This package is even smaller than the SOIC, designed for high-density PCB designs where space is limited.

LM393 Comparator Packages:

• DIP (Dual In-line Package): Just like the LM358, the LM393 is often found in the traditional 8-pin DIP. This is ideal for through-hole mounting.
• SOIC (Small-Outline Integrated Circuit): This is an SMT (Surface Mount Technology) package for the LM393 that also has 8 pins.
• MSOP (Mini Small Outline Package): The MSOP is essentially an even smaller version of the SOIC.

All packages have similar functionality but are intended for different assembly processes and applications. Through-hole packages like DIP are often used for prototyping and hobbyist applications, as they're easier to solder manually and insert into breadboards. In contrast, the smaller SMT packages are typically used for industrial manufacturing where high component density and automation (like pick-and-place machines) are essential.

Please be aware that package availability can vary depending on the manufacturer and the specific model of the IC. Always check with the manufacturer or distributor to determine the packages available for the specific version of the LM358 or LM393 you are interested in.

What are the Major Differences Between LM358 and LM393?

While the LM358 and LM393 are both commonly used integrated circuit chips, the two perform distinct functions and hence have several key differences. Here are the main points to consider:

1. Type of Component:

   • The LM358 is a dual operational amplifier (Op-Amp), which means it essentially amplifies the difference of voltages between its two inputs. It is intended primarily for linear applications.
   • The LM393 is a dual comparator, which means it compares two voltages and gives a binary output indicating which input voltage is greater. It is intended primarily for switching or digital (on/off) applications.

2. Output Signals:

   • The LM358 outputs a continuous, analog signal that is the amplified difference of the voltages applied to its inputs.
   • The LM393 has a digital output: it outputs a logic high or low (binary output) depending on whether the non-inverting input voltage is higher or lower than the inverting input voltage.

3. Output Configuration:

   • The LM358 has a push-pull output capable of sourcing or sinking current, and it can operate in any quadrant.
   • The LM393 features an open collector output. This means the device can only sink current; it cannot source current. For a valid 'high' output signal, an external pull-up resistor is often required.

4. Power Requirements:

   • The LM358 typically uses more power due to a higher quiescent current.
   • The LM393 uses less power, ideal for power-sensitive or battery-powered applications.

5. Slew Rate and Switching Speed:

   • The LM358 generally has a slower slew rate and switching speed, which is suitable for linear or low-frequency applications.
   • The LM393 is designed to operate faster, making it appropriate for high-frequency or digital applications.

It's crucial to refer to the datasheets supplied by the specific manufacturer of your LM358 or LM393 for the most accurate information regarding these chips. This will ensure you understand the device's electrical characteristics, internal layout, maximum ratings, package options, and more.

Conclusion

In conclusion, the LM358 operational amplifier and the LM393 comparator are both versatile components used extensively in electronics, each serving distinct functional roles:

• LM358 Op-Amp is typically used in analog circuits where amplification or linear voltage manipulation is needed. It is a dual-channel op-amp well-suited for signal conditioning, active filtering, audio pre-amplification, and other similar applications that require the output to provide a continuous range of voltages.

• LM393 Comparator is used primarily for comparing an input voltage with a reference voltage and providing a discrete digital output indicating which is higher. It serves well in digital circuits where binary decisions or direct interfacing with digital logic is essential. Common applications include zero-crossing detection, voltage monitoring, and driving relay or MOSFET gates.

It's critical to choose the right component based on the application's requirements: the LM358 for linear, analog operations, and the LM393 for fast, digital switching tasks. Users who require complete technical specifications should refer to the manufacturer's datasheet for each of these parts for the most accurate and detailed information. Remember, practical electronic design is not just about understanding individual component specifications and features, but also about how these components work together within a system to achieve the desired function.