What is CA3140 BiMOS Op-Amp & Its Working

The CA3140 BiMOS op-amp mainly combines the benefits of & bipolar transistors on a monolithic IC. This op-amp is integrated with the input of MOSFET & the output of bipolar within an 8-pin DIP package. The general purpose IC like CA3140 comes with 4.5MHz of frequency. This op-amp extends the benefits of both the high voltage PMOS transistors & bipolar transistors on a single chip. This article discusses an overview of a CA3140 op-amp.


What is CA3140 BiMOS Op-Amp?

The CA3140 is a BiMOS op-amp that combines the benefits of PMOS transistors with bipolar transistors on a chip. These operational amplifiers are gate-protected PMOS transistors within the circuit. These ICs provide high-speed performance, extremely high input impedance & low input current.

CA3140 BiMOS Op-Amp
CA3140 BiMOS Op-Amp

The voltage supply required for these op-amp ranges from 4V to 36V and these amplifiers are phase compensated internally to attain constant operation within the unity gain follower process. In addition, it has an access terminal for an extra capacitor if the extra frequency is required.

This IC is applicable in active filters, comparators which are accessible through 4.5MHz frequency and it is also used within tone controls & power supplies. This amplifier is ideal for typical amplifier applications and function generators.

This IC is approximately equal to CA3240 but the main disparity is the number of ICs within the package. The CA3240 CI is cost-effective & more compact, includes two op-amps within the package whereas CA3140 includes a single op-amp within the package.

The CA3140 amplifier includes two offset null pins like pin1 & pin5 which are used in the package to regulate the offset error. Once the voltage disparity between inverting & non-inverting pins is zero afterward the equivalent o/p voltage should be zero. Similarly, if the voltage difference is not zero then it is called offset error that can be adjusted through these two offset pins.

CA3140 BiMOS Op-Amp Pin Configuration

The pin configuration of CA3140 BiMOS Op-Amp is shown below. This kind of operational amplifier includes 8-pins where each pin and its functionality are discussed below.

CA3140 Op-Amp Pin Configuration
CA3140 Op-Amp Pin Configuration
  • Pins 1 & 5 (Offset Null): These pins are used to regulate offset error
  • Pin2 (IN-): This is an inverting pin of an IC
  • Pin (IN+): This is a Non-inverting pin of an IC
  • Pin4 (GND): This is a ground pin
  • Pin6 (O/P): This is an output pin
  • Pin7 (Vcc): This is the voltage supply pin
  • Pin8 (Strobe): This pin is mainly used for compensation of phase or to deactivate the output phase.

Features & Specifications

The features and specifications of the CA3140 BiMOS operational amplifier include the following.

  • PDIP Package with 8-pins
  • Through-hole mount
  • Input current is very less like 10pA @ ±15V
  • Supply ranges from 4V – 36 V
  • A subcategory is an operational amplifier
  • Dula terminal position
  • Input impedance (Zin) is extremely high like 1.5TΩ
  • O/p current for each channel is 40 mA
  • Gain of voltage is 100 dB
  • Gain Bandwidth Product (GBP) is 4.5 MHz
  • The current supply is 4mA
  • Slew Rate (SR) is 9 V/us
  • Common Mode Rejection Ratio/ CMRR is 70 dB

Equivalent CA3140 op-amp is UA741 whereas alternative CA3140 op-amps are AD620, IC6283, LM4871, JRC45558, LF351N, TL081 & MC33171N

Detection of Static Electricity using CA3140 IC

The circuit diagram of static electricity detector with CA3140 IC. The following circuit is very responsive, so used to detect electricity from a distance of 2 or 2 meters. This circuit operates with 6V/9V/12V DC. This circuit can also be used for different purposes like an electric field detector to detect electric current within electric wires through measuring equipment like millimeters and iron detectors.


Static Electricity Detection with CA3140 BiMOS Op-Amp
Static Electricity Detection with CA3140 BiMOS Op-Amp

Designing this circuit is very simple by using basic electronic components like 9V to 12V battery, 2N4401 transistor, antenna, LED, CA3140 IC & Resistors but CA3140 IC plays a key role because it is a high-performance op-amp. In the following circuit, the output of this op-amp is given to the transistor 2N4401to drive an LED.

In the above circuit by using CA3140 IC, static electric energy can be detected & amplified in the region of the antenna. The signal which is amplified can be accessible at the output pin of the IC like pin6. This IC is connected to the transistor so that LED can be activated. The height of an antenna used in the circuit is 8 inches and it is arranged vertically within the air.

CA3140 BiMOS Op-Amp Design Parameters

The design parameters of CA3140 IC are shown below.

Offset Voltage

The input offset voltage of this IC can be canceled through a 10K pot by connecting it in between the two terminals like 1 & 5 where its wiper can be returned to the ground. Thus, a considerable section of the potentiometer revolution is not completely used.

Voltage Operation is Less

This IC can be operated through less voltage like 4V. A current regulator with the PMOS threshold voltage keeps a stable operating current & thus reliable performance will be down to these lower voltages.

Bandwidth & Slew Rate

The open-loop -3dB BW can be reduced when an exterior capacitor is connected in between two Terminals like 1 & 8. The slew rate can also be reduced proportionally through this extra capacitor. So, a 20% decrease within BW through this method will also lessen the slew rate by 20%.

Consideration of Input Circuit

The inputs of an amplifier can be determined under the potential of terminal 4, however, a current limiting resistor is suggested to restrict the highest input terminal current to less than 1mA to prevent damage to the input protection circuitry.

Additionally, some resistance for limiting the current must be provided in between the inverting input & the output once the IC is used as a voltage follower with unity gain.

This resistance stops the very large i/p signal transient possibility from a signal force using the input safety network & directly driving the internal constant current source which could affect positive feedback through the output terminal.

MOSFET devices exhibit small changes within characteristics due to the huge differential input voltage application that are maintained above long phases at elevated temperatures. These changes can be accelerated by applying voltage & temperature. The procedure is reversible & offset voltage moves the opposite polarity to reverse the offset.

CA 3140 op-amp is an excellent IC used in signal detection circuits. The main characteristics of this IC are input current usage is less & the zero o/p within the off condition. Some of the normal operational amplifiers will not provide a zero o/p within the off condition that will influence the performance of the other circuits. In addition, the requirement of the input current in most of the ICs is also high so that these ICs cannot be utilized in different circuits depending on Infrared Sensors & Photodiodes.

Where to use/Applications

The applications of CA3140 IC include the following.

  • CA3140 op- amp is available in a single package and is widely used by students, engineers in different applications
  • This IC is used in general purpose applications like buffers, amplifiers, comparators, adders, voltage followers, etc
  • Intrusion Alarm Systems
  • This Op-amp is apt for designing some basic circuits for beginners, engineers, etc.
  • Used in Portable Instruments
  • Sample and Hold Amplifiers
  • Multivibrators & Timers with Long Duration
  • Power supplies & tone controls
  • Function Generators
  • Comparators
  • Peak Detectors
  • Active Filters
  • All Typical Op-Amp Applications
  • Photocurrent Instrumentation
  • Active Filters
  • Interface in 5V TTL Systems & Low Voltage Supply Systems

Thus, this is all about an overview of the CA3140 BiMOS op-amp datasheet, and this IC includes MOSFET inputs & Bipolar output. This IC combines the benefits of PMOS transistors as well as bipolar transistors with high voltage. This CA3140 IC includes PMOS transistors with a gate protected within the input circuit for providing extremely high i/p impedance like 1.5T Ohms. Here is a question for you, what is the temperature range of CA3140 BiMOS Op-Amp?

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