LM393 IC: Pin Configuration, Circuit Diagram, and Its Working

The IC LM393 has two internally inbuilt operational amplifiers which are internally compensated with frequency. These ICs are specially designed for performing their different tasks using a single power supply. It can also execute its functions properly with split power supply. The supply of current-drain does not rely on the amount of the power supply. One of the most important features of this IC is, it includes ground in its common mode input voltage. The applications of this IC mainly include various fields in real life, and also industrial, ADC (analog to digital converters), electrical systems powered by the battery, time-delay generators limit comparators, etc. This article discusses an overview of LM393 IC and its working.

What is LM393 IC?

The LM393 is a dual independent accuracy voltage integrated circuit operated with single or else split supply. These ICs comprises two independent voltage comparators to operate from an only power supply more than a wide variety of voltages. Working with two supplies is also achievable as long as the variation among the two supply voltages is 2 volts to 36 volts, & VCC is minimum 1.5 volts extra positive than the i/p voltage. The main features of this IC mainly include the following.

  • Single voltage supply ranges from 2.0 Vdc toward 36 Vdc
  • Split supply range will be from +1.0 Vdc or -1.0 Vdc to +18 Vdc or -18 Vdc
  • Little Supply Voltage of Current Drain Independent is 0.4 mA
  • The input bias current is low that is 25nA
  • Input offset current is low that is 5nA
  • Both the range of differential input as well as Power Supply Voltage are equivalent
  • The output voltage is well-suited by ECL, MOS, DTL, TTL, & CMOS Logic Levels
  • Electrostatic discharge bolts on the inputs to enhance the device roughness without troubling its performance

LM393 IC Pin Configuration

This IC includes 8-pins and every pin of this IC has the different feature from each other. The eight pins of this IC are listed below.

LM393 IC pin Configuration
 LM393 IC pin Configuration
  • Pin1 (OUTA): Output A
  • Pin2 (In A-): Inverting input A
  • Pin3 (In A+): Non-inverting input A
  • Pin4 (GND): Ground
  • Pin5 (INB+): Non-inverting input B
  • Pin6 (INB-): Inverting input B
  • Pin7 (OUTB): Output B
  • Pin8 (Vcc): Voltage Supply

LM393 IC Package & Dimensions

The Packages of LM393 has introduced for the different forms of a similar IC.

  • The LM 393IC package is SOIC (8), and the part number is LM393N.
  • These ICs are available in different packages with different dimensions for their easy separation
  • The package and dimension of LM 393 IC will be SOIC (8) and 4.9 X 3.91

LM393 IC Ratings

The ratings of LM393 IC mainly include an amount of current, voltage & required power for that particular IC.

  • The input voltage of this IC ranges from -0.3V to 36V
  • Differential i/p voltage is 36V
  • Lead temperature is 2600C
  • Power Dissipation is 660mW
  • Storage temperature is -65 0C/W to 150 0C/W

LM393 IC based Night Light Circuit

This circuit uses a photoresistor for controlling the circuit of a voltage divider. When this circuit absorbs to bright light, then the output device will be turned off. When the circuit absorbs the darkness then the output device will be turned off. This circuit works on a voltage comparator principle. If the inverting terminal of the IC voltage is high than the non-inverting terminal, then the output device activates. Similarly, if the inverting terminal of the IC voltage is low than the non-inverting terminal, then the output device deactivates. Here, this circuit uses a LED as an output device.

The required components of this circuit mainly include IC LM393, a photoresistor or light sensor, resistors 33KΩ & 330Ω, potentiometer, LED, battery for power supply. This IC has two power inputs namely Vcc & GND, where Vcc is the positive voltage supply which can be as higher as 36V, and the GND is the ground wire of the source of the voltage. The power lane can be completed with these two terminals, and give the supply for this operation.

Night Light Circuit using LM393
Night Light Circuit using LM393

The IC LM393 includes two op-amps internally and each op-amp has two inputs as well as one output. These ICs works independently to provide its own output. But, this circuit uses only one operational amplifier and the other op-amp will not be connected. Both the op-amps are necessary only when we use complex circuits for monitoring numerous levels. This circuit checks only one level so it uses one op-amp.

Once the power is applied to the IC, compare the voltage values. If the inverting terminal voltage is high than the non-inverting, then the op-amp output will be fall to the ground, and the flow of current will be from positive supply to GND. Similarly, if the voltage of the inverting terminal is low than the non-inverting, then the op-amp output will stay at the positive voltage supply (Vcc), and there is no flow of current because there is no potential difference across the load.

So, when the voltage of the inverting terminal is high then the load will be turned ON. When the voltage of the inverting terminal is low then the load will be turned OFF. Here the LED is used as a load. The night light circuit using LM393 is shown below. This circuit uses a LED as a load, and a photoresistor is used to detect light. The resistance of the photoresistor mainly depends on the light hits on the surface. When the photoresistor detects the darkness, the resistance of the photoresistor will be high, and when the photoresistor detects the bright light, its resistance will be decreased.

So if we connect a voltage divider circuit using a photoresistor as well as a fixed resistor. If it detects the darkness, then the photoresistor will utilize more voltage, because it has less resistance in dark. Similarly, if it detects to bright light, then the photoresistor will utilize less voltage.

If the op-amps non-inverting terminal’s input is a good reference voltage, and the voltage of the photoresistor goes high than the reference voltage if exposed to the dark, and low than the reference voltage if exposed to light, we have designed a comparator circuit which acts differently for when there is night then there is light. So the LED will turn ON throughout darkness and OFF in bright light.

Thus, this is all about LM393 IC and its application. The LM393 IC is a low-power, single supply, low-offset voltage, double, differential comparators. Generally, a common comparator IC is a tiny voltmeter by included switches. It is used to calculate the voltages at two dissimilar terminals and contrasts the dissimilarity in voltage quantity. If the voltage of the first terminal has a high-voltage than the second terminal, the switch will activate. But, if the first terminal has a low-voltage than the second terminal, the switch will deactivate. Here is a question for you, what are the applications of LM393 IC?

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