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Home > Other > LM741 Op-AMP IC Pinout, Circuit, Datasheet, and Uses

LM741 Op-AMP IC Pinout, Circuit, Datasheet, and Uses

Update Time: 2023-12-13 15:23:20

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Within the extensive realm of electronic components, the LM741 operational amplifier (op-amp) occupies a distinctive position. Its versatility and enduring popularity render it a fundamental element in numerous electronic circuits. The LM741 op-amp is a DC-coupled high-gain electronic voltage amplifier containing only one op-amp. This operational amplifier IC serves as a comparator, analyzing two signals—the inverting and non-inverting signals. Primarily designed for mathematical operations in diverse circuits, op-amps boast significant amplification and are commonly employed as voltage amplifiers. The LM741 can function with either a single or dual power supply voltage. In this article, we'll discuss the LM741 pinout, circuit, datasheet, and explore where & how to Use this op-amp IC.


What is LM741 Op-amp IC?


The LM741 series comprises general-purpose operational amplifiers that exhibit enhanced performance compared to industry standards like the LM709. In most applications, they serve as direct plug-in replacements for the 709C, LM201, MC1439, and 748. These amplifiers have features that make their application nearly foolproof, including overload protection on the input and output, immunity to latch up when the common-mode range is exceeded, and freedom from oscillations.


The LM741 operational amplifier is a high-gain electronic voltage amplifier with a DC coupling. It features only one LM741 op-amp, operating as a comparator by comparing the two signals: the non-inverting and inverting signals.


The primary function of this IC is to execute mathematical operations in circuits. The LM741 can function with either a dual or single power supply voltage. Most op-amps exhibit large gains and are commonly utilized as voltage amplifiers.


LM741 Op-amp IC.jpg


LM741 Pinout


The LM741 is equipped with eight pins. The initial and fifth pins serve as the offset and null pins, crucial for aligning the input voltage and mitigating offset voltage. The second pin functions as the input for the inverting signal, while the third handles the non-inverting signal.


Pin four corresponds to the negative supply voltage, while pin seven pertains to the positive supply voltage. The sixth pin serves as the output pin, and the eighth is designated NC (not connected).


Presented below is the pinout diagram schematic for the LM741.


LM741.jpg

LM741 op-amp pinout diagram


Pin Configuration


The configuration comprises eight pins, with two allocated for power supply denoted as Vcc- and Vcc+. In summary, the table provides descriptions for each pin.


Pin No.Pin NameI/ODescription
1Offset N1IOffest pin 1 is for external input offset voltage adjustment
2Inverting InputIInverting input for applying the inverting input voltage
3Non-Inverting InputINon- inverting input  pin for applying a non-inverting input voltage
4-VccIVcc- is for applying negative DC supply
5Offset N2IOffset Null 2 is for external input offset voltage adjustment
6OutputO
Output pi is for obtaining output voltage
7+VccIVcc+ is for applying positive DC supply
8NCN/A
This pin is for no connection i.e. it is to be kept open


Here is the pin function details:


  • Pin 1: Offset N1 - To eliminate offset voltage and achieve complete balance in input voltages, voltage is applied to this pin. Further details on offset terminals can be found below.

  • Pin 2: Inverting Input - The positive part of the input signal intended for amplification, with inversion, is connected to this pin. If non-inverted amplification is desired, the positive signal component is placed in the Non-inverting terminal, and the negative or ground part is connected here.

  • Pin 3: Non-inverting Input - This pin receives the positive part of the input signal for non-inverted amplification.

  • Pin 4: V- - As the LM741 Op amp requires a dual power supply (positive and negative DC voltage), Pin 4 serves to supply the op amp with negative DC voltage.

  • Pin 5: Offset N2 - Similar to Pin 1, this pin is used to introduce voltage for offset elimination and achieving input voltage balance. Additional details on offset terminals are provided below.

  • Pin 6: Output - The amplified signal output is routed through this terminal, connecting to whatever device the amplifier is driving.

  • Pin 7: V+ - This terminal is where the positive DC voltage is supplied.

  • Pin 8: NC - Abbreviating "Not Connected," this pin is unused and should be left open.


Feature & Specifications


Ensuring overload protection is a paramount feature of this operational amplifier (op-amp), extending safeguarding to its inverting and noninverting pins. Its distinctive characteristics setting it apart from other op-amps include:


  • Single Op-Amp Configuration: LM741 houses a singular op-amp, distinguishing it from multi-op-amp counterparts such as LM358, LM148, LM248, and LM348.

  • Short Circuit and Overload Protection: Equipped with protective measures against short circuits and overloads.

  • Oscillation-Free Operation: Demonstrates freedom from undesired oscillations.

  • Low Power Consumption: Exhibits low power consumption.

  • Ample Common Mode Rejection Ratio (CMRR) and Differential Voltage Ranges: Displays substantial CMRR and broad differential voltage ranges.

  • No External Frequency Compensation Requirement: Operates efficiently without needing external frequency compensation.

  • Latch-Up Prevention: Features a built-in mechanism preventing latch-up occurrences when the common-mode range is exceeded.

  • Power Consumption Levels: This IC's nominal, standard, and maximum power consumption are ±10V, ±15V, and ±22V, respectively.

  • Operating Temperature Range: Suitable for operation within the temperature range of -50 to 125 °C.

  • Supply Current: Draws a supply current in the range of 1.7 to 2.8mA.

  • Soldering Pin Temperatures: The PDIP package endures temperatures up to 260 °C for 10 seconds, while TO-99 and CDIP can withstand 300 °C for the same duration as specifications.

  • Available Packages: Offered in TO-99, CDIP, and PDIP packages.


LM741 Circuit


LM741 Schematic Diagram


LM741 Schematic Diagram.jpg


LM741 Circuits Examples


LM741 finds application in various circuit configurations, including:


  • Voltage follower

  • Unity gain inverting amplifier

  • Bilateral current source

  • AC/DC converter

  • Instrumentation amplifier

  • Square wave generator

  • Voltage comparator

  • Power supplies

  • Oscillators

  • Half-wave rectifiers


In summary, this op-amp is a common choice in numerous electronics projects.


Unity Gain Amplifier Example


As previously discussed, one operational amplifier (OP-AMP) application is as a unity gain or buffer amplifier. Unity gain amplifiers can function as followers or inverters.


The follower imparts a gain of one, delivering an output identical to the input. Conversely, the inverter provides unity gain and reverses the input polarity. The Op-AMP's output resistance is negligible, enabling it to supply current as per the load requirements.


The provided diagram illustrates a noninverting unity gain amplifier. In this scenario, the input equals the output.


lm741-unity-gain-amplifier-example.png


For instance, by applying a 6-volt input voltage and incorporating a feedback resistor, the output voltage remains precisely 6 volts. This is attributed to the unity gain of the amplifier, resulting in an output of 6 volts on the oscilloscope. The equation expresses this relationship:


Vout = Vin x Gain 

Vout = 6 x 1 = 6 volts   // Because gain=1 and Vin=6 volts


lm741-unity-gain-amplifier-example-output.png


LM741 Square Wave Generator Example


This square wave generator transforms an AC sine wave into a square wave, which is a zero-crossing detection circuit. Essentially, its primary role is to generate a square wave from a sine wave.


LM741-square-wave-generator-example-.png


In the provided illustration, the LM741 operates as a comparator. It assesses the voltage magnitude by comparing the zero voltage reference with the sine wave. Each time the sine wave crosses the zero voltage level, a square wave is generated at the output. The comparator yields +15 and -15 volts as output, but we employ edge detection circuits. These edge detection circuits convert the op-amp output into a square wave.


LM741square-wave-generator-example-output.png


LM741 Equivalents


LM741 equivalents include LM741A, LM741C, LM709C, LM201, MC1439, and LM748.


LM741 Applications


  • Comparators

  • Multivibrators

  • DC Amplifiers

  • Summing Amplifiers

  • Integrators

  • Differentiators

  • Active Filters

  • General feedback applications

  • on our mobile phones for AD conversion

  • In Audio amplifiers

  • Programmable logic controllers

  • Video signal conditioning units

  • Processors

  • Sensor Data Accusation

  • digital to analog converters in Phone

  • Temperature sensors and controllers

  • error amplifiers

  • communication circuits

  • Mobile phone chargers

  • Receivers

  • Modulators

  • Synthesizers


LM741 Advantage


The LM741 stands as a versatile operational amplifier integrated circuit with multiple features. It is offered in various packaging options. Housing a total of 20 transistors in its internal circuitry, this IC is well-suited for diverse analog applications. Its high gain, low current consumption, and broad supply voltage range make it particularly fitting for battery-operated circuits. Additionally, the IC is equipped with overload protection on both input and output ends, safeguarding its internal circuitry from potential damage due to overloads.


How does LM741 Working


If the voltage at the non-inverting input (+) exceeds that at the inverting input (-), the comparator's output is set to HIGH. Conversely, when the voltage at the inverting input (-) surpasses that at the non-inverting input (+), the output is configured as LOW. The operational amplifier's output is determined by the product of the gain and the input voltage.


Where and How to Use LM741?


An operational amplifier (op-amp) can be employed in two configurations:


1. Inverting Op-amp:


The op-amp operates in an inverting mode when the input source is linked to the inverting terminal (PIN 2) and connected to the feedback with the output (PIN 6). For instance, if PIN 2 exhibits a positive polarity, the output from PIN 6 will manifest a negative polarity.


GAIN = Rf/R1


Inverting Op-amp.jpg


2. Non-inverting Op-amp:


In this setup, the input source is attached to the non-inverting terminal (PIN 3), and PIN 2 is linked as feedback with the output (PIN 6), placing the op-amp in a non-inverting state. If PIN 3 displays a positive polarity, the output from PIN 6 will exhibit a positive polarity.


GAIN = 1+ (Rf/R1)


Non-inverting Op-amp.jpg


For example, it serves roles as a


  • Buffer

  • Unity gain follower

  • Comparator


When utilizing the LM741 operational amplifier, the input signal is applied to the inverting or non-inverting input terminals, denoted as pin 2 or 3. The DC supply voltage is provided to pin 4 and pin 7.


  • Connect the negative terminal of the battery to pin 4, and subsequently, link the positive terminal to pin 7.

  • It is crucial to ensure that +Vcc and –Vcc are of equal magnitude.

  • The maximum values of ±Vcc are detailed in the features or datasheet table. Similarly, the output voltage is accessed at pin 6.

  • Additionally, Pin 1 and 5 are employed for null offset adjustments. Pin 8 is designated as NC, signifying that it should not be connected to any external circuit.


Null offset adjustment Circuit


Distinct circuit arrangements are available for implementing typical null offset adjustments, and the following represents one such configuration.


LM741-op-amp-configuration-circuit.png


The input offset voltages encountered in operational amplifiers (OP-AMPs) arise from discrepancies stemming from collector currents, collector gains, and collector and emitter resistors. However, these disparities can be rectified by utilizing offset adjustment pins. Moreover, a potentiometer or variable resistor is linked between pins 1 and 5 to adjust the circuit precisely.


Precautions for use LM741


LM741 Application Notes


Action mode and principle


The LM741 operational amplifier is widely employed for various applications. Featuring inverting and non-inverting input terminals, it accepts current or voltage signals for amplification, delivering the amplified output through its output terminal. Notably, this amplifier necessitates paired positive and negative power supplies of equal magnitude, typically ranging from ±12Vdc to ±18Vdc, with ±15Vdc commonly used. The appearance and pin configuration of the LM741 are depicted above.


Utilizing the LM741 requires the provision of paired positive and negative power supply voltages, denoted as +Vdc and -Vdc, on pin 7 and pin 4. If a voltage discrepancy exists between pin 2 and pin 3 (the two input terminals), this difference is amplified and presented at the output. The operational amplifier exhibits a characteristic where the output voltage remains within the range of the positive power supply voltage +Vdc to the negative power supply voltage -Vdc. If the input voltage difference exceeds this range, the output voltage saturates at +Vdc or -Vdc, as illustrated in the figure below.


Amplifier I O Voltage Graph.jpg

Amplifier I/O Voltage Graph


The fundamental operation of the LM741 is demonstrated in the figure below. When a voltage is applied to the non-inverting input terminal, the output yields an amplified signal of the same polarity—conversely, inputting the same voltage signal to the inverting input terminal results in an output signal with the same amplification but opposite polarity. Simultaneous input of voltages to both input terminals involves subtracting the voltage value (V2) of the inverting input terminal from the voltage value of the non-inverting input terminal (V1). The output is obtained by multiplying this ratio at the output terminal (V1-V2).


basic operation of the LM741.jpg


Power supply


The power supply features two external jacks, facilitating dual power outputs. To achieve positive and negative voltage output, the Tracking button on the power supply is employed, as illustrated below. For instance, to generate ±15Vdc, connect the positive terminal of one power output set to the negative terminal of the other set. The remaining unconnected terminals serve as the power output terminals. Power on the supply, press the Tracking button on the instrument panel and use the adjustment knob to set the desired ±15Vdc voltage.During adjustment, rotating the adjustment knob for one power output set affects both sets simultaneously. The displayed values are identical, with one end indicating positive and the other negative, yielding an output of 15Vdc. This principle resembles connecting two batteries in series.


Power supply.jpg


When the amplifier circuit and sensing element integrate into the test equipment, the power supply cannot cater to the operational amplifier's power needs. A self-made ±15Vdc power supply circuit is essential. This involves using a bridge rectifier, voltage regulator ICs, and appropriate capacitors to convert the standard 110-volt power supply into a ±15Vdc power supply. The circuit diagram is depicted below. After passing through the bridge rectifier, the 110-volt power supply utilizes the three-terminal voltage regulators IC7815 and 7915 to adjust the voltage to ±15Vdc. Specifically, 7815 acts as a positive voltage regulator, stabilizing the voltage at +15Vdc, while 7915 handles negative voltage adjustment.


power supply circuit.jpg


How to Safely Long Run LM741 in Circuit


To ensure prolonged and optimal IC performance of ICs, operating them below their maximum specified values is advisable. For long-term usage of the LM741 IC in your projects or devices, it is recommended not to exceed a power consumption of 500mW. The operating voltage should be maintained between 10 volts (minimum) and 22 volts (maximum). Decoupling power supplies by incorporating a 0.1uF capacitor is crucial, positioning it close to the IC within your circuit for optimal outcomes. Furthermore, the IC should be stored and operated within the temperature range of -55 to +125 degrees Celsius.


How to Connect the LM741 Op Amp Chip to a Circuit


In this section, we will utilize it as an amplification component.


Now, let's establish the connections for the LM741 to achieve a 10-fold amplification.


This circuit configuration for the LM741 Op Amp will result in a 10x amplification, signifying that the output signal will be ten times greater than the input signal.


LM741 Op Amp Chip to a Circuit.jpg


Apply +15VDC to pin 7 and -15VDC to pin 4. This step is crucial to provide bias power to the op-amp, enabling it to execute the amplification function. The op-amp cannot function without this DC power.


When connecting the signal input to the inverting side of the op-amp, the voltage output is determined by the formula:


voltage output.png


The gain of the op-amp is given by:


gain of the op-amp.png



To adjust the op-amp's gain, you can vary the resistance value for Rf. Increasing Rf will raise the gain, while decreasing Rf will lower the gain.


This is the procedure for connecting an LM741 Op-amp for amplification.




LM741 Package


LM741 Package.jpg


What is the difference between LM741 and LM358?


LM741 and LM358 serve as classic and readily accessible general-purpose op-amps, yet a detailed comparison reveals that LM358 outshines LM741 in various aspects.


LM741LM358
Operates with dual supplyFunctions with a single supply
Has an input common-mode range that does not include either supply rail, requiring at least 2V above and belowHas an input common-mode range that includes the negative supply rail and extends up to 1.5V below the positive supply rail
Exhibits relatively higher bias currentDemonstrates relatively lower bias current
Being the older part, is not recommended for new designsEasily available, cost-effective, and suitable for general purposes
Consists of a single amplifier in a packageIncorporates dual amplifiers in a single package, with a quad version also available


The following is the specification differences:


SpecificationLM741
LM358
Supply voltage (max.)±22V32V (±16V)
Input bias current (max.)~200nA100nA
Input voltage range (max.)±13V (±15V supply)0V – (V + - 1.5V) (30V supply)


LM741 Datasheet


Download LM741 Datasheet PDF.


Conclusion


LM741 stands out as a versatile operational amplifier with several noteworthy features. To begin, it offers null-offset adjustment capability through two dedicated pins. Additionally, it excels in voltage follower circuits, proving to be an optimal choice due to its absence of latch-up. The wide common-mode input voltage range eliminates the need for external components to achieve stability. The internal frequency compensation further contributes to its stability. Notably, the device is equipped with short-circuit protection. A small potentiometer can be effectively employed to nullify offset voltage. Operating within the 0-70°C temperature range, this operational amplifier emerges as the preferred option for analog circuits.


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FAQ

  • What is the function of LM741?
  • The LM741 stands out as a widely employed integrated circuit for operational amplifiers, adept at executing mathematical operations and amplification functions.

  • What is the current limit on a 741 op-amp?
  • The current limit on 741 IC op-amp is around 25 mA.

  • What is the maximum supply voltage for LM741?
  • 18 volts.

  • What are the limitations of LM741?
  • If the targeted output signal includes a component with a voltage variation surpassing the slew rate, the operational amplifier (op-amp) will encounter limitations in replicating the signal. This condition is termed slew-rate limitation.

  • What does LM stand for in LM741?
  • Linear monolithic.

  • What are the differences among LM741, LM358, and LM324?
  • Number of channels: LM741 has a single channel, LM358 features dual channels, and LM324 has four channels; Working voltage range: LM741 operates within 7V36V, while LM358 and LM324 have a working range of 3V32V; Unity gain bandwidth: There's a slight variance, with LM741 and LM324 at 1MHz and LM358 at 700kHz; Accuracy: LM741 has a maximum input offset voltage of 6mV, whereas LM358 and LM324 are both at 7mV, nearly identical; Input impedance: LM741 and LM358 exhibit lower input impedance with input bias currents in the μA range, while LM324 boasts a higher input impedance at 90nA, several times greater than the former two.


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