What is the LM4558 IC : Pin Configuration & Its Working

There are different kinds of dual operational amplifiers are available in the market like LM258, LM358, LM158, LM2904 & LM747. These ICs mainly include two op-amps with high gain, independent, internally compensated with frequency. These ICs were mainly designed for operating from a single power supply on a broad range of voltages. This article discusses an overview of an LM4558 IC and its working.


What is the LM4558 Dual Op-Amp?

LM4558 is one kind of IC that includes dual op-amps with high gain. This IC comes under the LMxx family where this series is invented by National Semiconductor. In the LM series, the term LM stands for linear monolithic. This IC is an analog component that is incorporated into a single Si piece. This Op-Amp is protected with a short circuit & the compensation of internal frequency will ensure stability without exterior components.

LM4558 IC
LM4558 IC

This is a monolithic IC where the two op-amps reside within a single package; however, they function separately from each other & share similar power rails. In this IC, the two op-amps include less noise interference between them to make this IC ideal to use in several applications.

Here, an advanced epitaxial process is used to compensate & construct a dual op-amp internally on a single IC. Unique performance characteristics of this chip can be obtained by combining the NJM741 IC features through the matching & tracking of the close parameter of a dual device on a monolithic IC.

In single NJM741op-amp applications, an outstanding channel separation permits the use of the double device to provide density. It is particularly well suitable for applications within differential-in, out & within potentiometric amplifiers and wherever phase & gain matched channels are compulsory.

LM4558 IC Pin Configuration

The pin configuration of the LM4558 dual op-amp is shown below. This dual op-amp includes 8-pins where each pin and its functionality are shown below. This IC is accessible in several packages where the user can select based on the requirement.

LM4558 IC Pin Configuration
LM4558 IC Pin Configuration
  • Pin1 (1OUT): This is the o/p pin of the first op-amp
  • Pin2 (1IN-): This is an Inverting input of the first op-amp
  • Pin3 (1IN+): This is the Non-Inverting i/p of the first op-amp
  • Pin4 (GND): This is a ground pin
  • Pin5 (2IN+): This is the Non-Inverting i/p of the second op-amp
  • Pin6 (2IN-): Inverting input of the second op-amp
  • Pin7 (2OUT): This is an o/p of the second operational amplifier
  • Pin8 (VCC): This is a power supply pin.

Features & Specifications

The features and specifications of LM4558 IC include the following.

  • These op-amps operate individually
  • Large common mode & differential voltage range
  • Less noise interference between two op-amps
  • Parameter tracking can be done on the range of temperature
  • Short circuit protection is continuous
  • Phase & gain match in between two op-amps
  • Compensation of frequency is not required
  • Supply operation ranges from +5.0 V to +15 V
  • No latch-up
  • Operating temperature ranges from 0ºC – 70ºC
  • Less noise i/p transistors
  • Operation of supply is dual +15V & -15V
  • Common-Mode Rejection Ratio (CMRR) is 80dB
  • Complete power dissipation is 200mW

Equivalent LM4558 dual op-amps are, LM258, LM158, LM358, LM747 & LM2904. This general-purpose dual op-amp is used to perform general-purpose op-amp operation circuits like comparator, mathematical operations, or differential amplification.

The high common-mode i/p voltage range & the lack of latch-up will make these ICs perfect for the applications of voltage-follower. Additionally, with these two ICs on board, the device can perform two different functions at a time in the application.

Voltage Controlled Oscillator with LM4558 IC

The operation of LM4558 IC can be simply explained with the help of a VCO (voltage-controlled oscillator) circuit. The circuit diagram of VCO is shown below. The designing of this circuit can be done by using different electrical and electronic components.


The designing of a VCO can be done by using two operational amplifiers but in place of using two ICs, you can also utilize RC4558 IC. At the pin2 of the input, the voltage which needs to control is applied and because of the voltage divider network allied between two pins like pins2 & 3 whereas the half of this voltage can be given to pin3.

Voltage Controlled Oscillator with LM4558 IC
Voltage Controlled Oscillator with LM4558 IC

In the above circuit, the first operational amplifier generates a waveform in triangular form by activating the op-amp. The current supplies from the 100k ohm of a resistor & after that it discharges the capacitor (0.05µF) which results in a triangular wave on its output.

This output of the primary op-amp is given to the input pin of the secondary op-amp using a 51kΩ resistor. In the above circuit, the secondary op-amp functions like Schmitt trigger and it verifies the input voltage.

Once this voltage is high than the threshold level, it will generate a HIGH signal at the o/p. If the i/p voltage drops under the threshold range, then the output will turn zero. So, in this manner, a square wave is generated at the output.

Multivibrator Circuit

Multivibrator circuit generates its input signal through an RC network. This network is connected like feedback in between inverting input & output pins. A voltage divider is connected in between the two terminals like non-inverting & output. Here, this circuit acts like a multivibrator & produces rectangular signals. The circuit diagram of a multivibrator is shown below.

Multivibrator Circuit
Multivibrator Circuit

Where to use/Applications

The applications of LM4558 dual op-amp include the following.

  • It is used in instrument measuring
  • It operates different mathematical operations like sum, differentiation, integration, etc
  • Used in the industrial-based applications
  • Used in amplifiers & oscillators
  • Integrated into the translation of logic voltage
  • Applicable in peak detectors & voltage comparators
  • It provides extremely little distortion & thus used in different circuits like phase shift and sine wave.
  • It is used for processing the signal, filtering, multivibrators, peak detectors, instrumentation, etc.
  • Square wave oscillator
  • DVD players
  • Audio Mixers
  • Voltage Follower
  • Lamp Driver

Thus, this is all about an overview of the LM4558 dual op-amp. This is a dual general-purpose operational amplifier where each half is similar to the 741 IC except offset null capacity is not provided. The range of maximum common-mode input voltage & latch-up absence will make this amplifier perfect for the applications of voltage follower. This IC is protected with a short circuit & the frequency compensation within this will ensure stability without using exterior components. Here is a question for you, what is dual op-amp?

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