TL084 Op-Amp : Pin Configuration & Its Applications

The TL084 op-amp is one kind of IC that includes four separate operational amplifiers where each amplifier works independently, so it is obtainable in Quad Package. The most similar op-amp to TL084 is the LM324 op-amp because these amplifiers are available in the same package and hold four operational amplifiers within it.

The working of both the operational amplifiers is similar but the required voltage to operate is different, TL084 op-amp uses 7V to operate whereas LM324 op-amp uses 5V. This article discusses an overview of the TL084 op-amp and its working with applications.

What is TL084 Op-Amp?

TL084 op-amp is a high-speed integrated circuit that includes two bipolar transistors and two high voltage JFETs. The main features of this IC are, high slew rate, the input bias current is low, and trimmed input offset voltage.

When TL084 op-amp is used then we need to check the working of four available op-amps within the package. If any of the op-amps stop working then some stay capacitance may be developed within the IC which affects the overall performance of IC. Additionally, unused op-amp uses more power, so the efficiency of the device may be reduced.

This op-amp is ideal in audio pre-amplifiers due to less noise & harmonic distortion. The inbuilt four ICs are responsible for the high input impedance & low bias current.

Once the device is saturated then TLO84 op-amp will not reach the maximum positive and negative voltage. So we will get a 2V supply because of the voltage drop that occurred through the transistors used in the operational amplifier.

Pin Configuration

The pin configuration of TL084 op-amp is shown below which includes 16-pins where each pin and its functionality is discussed below.

• Pins (1, 7, 10, and 16) – Output Pins: These pins are the four op-amp’s output pins
• Pins (2, 6, 11 & 15) – Input Inverting Pins: These pins are the four Op-Amps input inverting pins
• Pins (3, 5, 12 & 14) – Input Non-Inverting Pins: These pins are the four Op-Amps input non-inverting pins
• Pin 4 (Vcc (+)): This is the Op-Amp’s positive supply rail
• Pin 13 (Vcc (-)): This is the Op-Amp’s negative supply rail

Features & Specifications

The features & specifications of the TL084 op-amp include the following.

• The minimum operating voltage is 7V
• Input bias current is 20pA
• The input offset voltage is 3mV
• CMRR or common-mode rejection ratio is 86dB
• Gain is 200 V/mV
• Bandwidth is 4MHz
• The typical range of operating voltage is +18V to -18V
• Protection from output short circuit
• Available packages are SO-14, 14-pin PDIP & TSSOP
• Manufactured by Texas Instruments
• TL084 series
• The type of mounting is SMD or SMT
• Height is 4.57 mm, length is 19.3 mm & width is 6.35 mm
• It includes four channels
• Supply type is single or dual
• The type of input is rail to rail
• Power consumption is less per channel like 1.4mA
• Operation is latch-up free
• Input impedance is high
• Harmonic distortion typically is low like 0.003%
• Typical Input bias current is low like 30 pA
• Typical input offset current is low like 5 pA
• Wide common-mode & differential range of voltages

Equivalent TL084 op-amps are TL072, TL074 & LF353N whereas alternate TL084 Op-Amps are TL072 & LF353N.

TL084 vs TL074

The main difference between TL084 and TL074 include the following

• The TL084 op-amp is equivalent to TL074 op-amp except for high noise immunity and good offset characteristics. In TL084, the ‘84’ includes low offset, so applicable for DC signals. Similarly in TL074, the ‘74’ includes less noise, so applicable for AC signals.
• The DC performance of TL084 IC is better whereas the TL074 op-amp has better distortion performance & noise. So TL084 op-amps are used on the control paths whereas TL074 op-amps are used on the audio paths.

How to use TL084 Op-Amp/Circuit Diagram?

The low dynamic microphone pre-amplifier circuit using TL084 op-amp is shown below. Generally, TL084 op-amp is used in audio systems because it is a low-noise operational amplifier that is available at less cost.

This IC is available in a quad package similar to LM324/LM339. This op-amp uses BIFET technology so this IC has fast slew rates, wide bandwidths, less input bias currents, input offset currents & supply currents.

The required components to build this low dynamic microphone pre-amplifier circuit with TL084 IC mainly includes IC1 like TL084 JFET op-amp, resistors R1 = 10K & R2 = 1K, R3 & R4 = 100K, VR1=1M and Electrolytic capacitors like C1 & C2 = 1uF 50V.

The amplifier used in this circuit is inverting amplifier and it is convenient to use a single power supply from 4V to 5V. Here, both resistors like R3 & R4 are connected in voltage divider form whereas capacitors are connected to an audio device.

Once the MIC gets audio sounds then it changes into an audio signal. Here, this signal is transmitted through C1 and R2 to op-amp’s non-inverting pin-like pin3. The gain of this circuit can be controlled through resistor ‘R1’ & variable resistor ‘VR1’ by using this formula like Gain = VR1/R1. In this circuit, a low or medium impedance-based dynamic microphone is connected to this circuit.

Where to use TL084 Op-Amp/Applications

The applications of TL084 Op-Amp include the following.

• This op-amp is used in different circuits which need maximum input impedance
• Buffer applications
• Amplifier Circuits
• Used for audio pre-amplification
• Voltage generators with multi-stage
• Noise or audio filter circuits
• Sample & Hold amplifiers
• It is used to amplify the output signal of an active filter
• To design the internal circuits of multivibrators, comparators, function generators, square wave oscillators, peak detectors, etc
• It can be used to execute all typical op-amp-based applications because it is pin to pin compatible through the LM741 IC design.
• These ICs are used in notch filters to remove a single or number of frequencies.
• This op-amp is used in different application circuits which use maximum slew rate, less input bias current, wide bandwidth & offset voltage.
• It is used in ac-dc conversions, voltage followers, high-speed integrators, etc

Please refer to this link to know more about the TL084 op-amp datasheet.

Thus, the TL084 op-amp includes four separate operational amplifiers where each IC works independently. This IC is suitable in audio preamplifiers because of the less noise & harmonic distortion. In this IC, both the transistors and JFETs are responsible for the high input impedance and low bias current of the device. Here is a question for you, what is the main function of an operational amplifier?