What is LM709 IC : Pin Configuration & Its Applications

There are different types of LM series ICs available in the market. Some of them were commercially produced, known as the first analog ICs whereas others were modern innovations. The series of LM was invented with ICs by National Semiconductor. The prefix in the IC stands for linear monolithic, so this IC is used in general purpose applications. This article discusses an overview of LM709 IC, pin configuration & its working.


What is LM709 IC?

The LM709 IC is a monolithic op-amp and its function is specified totally on the voltages range. To provide a high gain, both bias current and offset voltage will be reduced. Further, the class-B output stage gives a large output capability with minimum power drain.

LM709 IC
LM709 IC

Exterior components are mainly utilized for compensating the frequency of the amplifier. Even though the compensation network of specified unity-gain will make the amplifier completely constant within the configurations of all feedbacks, so compensation is changed to reduce high-frequency performance for any gain.

The commercial-industrial edition of LM709C is LM709 and it is equal to the IC LM709 apart from that it is indicated from 0oC – a70oC operation.

LM709 IC Pin Configuration

The pin diagram of LM709IC is shown below. This IC is available in a dual inline package with 8-pin or 14-pin variants. So the 8-pin out of this IC is shown below where each pin of this IC and its function are described below.

LM709 IC Pin Configuration
LM709 IC Pin Configuration
  • Pin1: The compensation input-A pin is mainly used for the compensation of input frequency
  • Pin2: The inverting input of this pin is used for providing the inverting i/p voltage
  • Pin 3: The non-Inverting input pin is used for providing a non-inverting i/p voltage
  • Pin 4: This is –Vcc pin, used to provide negative DC supply
  • Pin 5: The compensation output pin is used for compensation of o/p frequency
  • Pin 6: This output pin is used for attaining an o/p voltage
  • Pin7: This +Vcc pin is used for providing +ve DC supply
  • Pin 8: This compensation input-B pin is used for compensation

Features

The features of LM709 IC include the following.

  • The input offset voltage is 5 mV
  • Junction temperature is -55 to +150 °C
  • Lead temperature is 300°C
  • Input bias current 500 nA
  • Duration of o/p short circuit is 5s
  • Slew rate like inverting amplifier is 2.5 V/ µs
  • Differential Input voltage is ±5V
  • The supply voltage rejection ratio is 150V/ µV
  • Power dissipation is 300 mW
  • Voltage gain for a large signal is 70V/mV
  • Voltage Supply is ±18V
  • The supply current is 5.5 mA
  • The supply voltage rejection ratio is 150 µV/V
  • The common-mode rejection ratio (CMRR) is 90 dB
  • Input resistance is 150 Ohms
  • Input offset current is 200 nA
  • Maximum o/p voltage swing ±14 V

Different Parameters

While designing any product based on the operational amplifier, it is essential to recognize different characteristics like the following.

  • Voltage Gain with Open Loop
  • Unity Gain
  • Input & Output Resistance
  • Peak-to-Peak Input Noise Voltage
  • Input Offset Current & Voltage
  • Gain-Bandwidth Product
  • Input Bias Current
  • Voltage Swing
  • CMRR
  • Slew Rate

How to Use?

Similar to LM741 IC, LM709IC is equivalent. This IC is a single operational amplifier. Once the voltage at the positive terminal is high as compared to the negative terminal, then the comparator’s output will be HIGH.

If the voltage of the negative terminal is high as compared to the positive terminal then the output of the comparators is low. So, the op-amp output is the product of the input voltage & the gain. This IC includes input & output compensation pins and these pins are mainly used to conquer the troubles linked with frequencies within an amplifier.

Where to Use/LM709 IC Circuit Diagram

The circuit diagram of LM709 IC is shown below. The required components to make this circuit mainly includes resistors with values 1kilo ohm, 18-kilo ohm, 680 ohms -2, a potentiometer (VR1) = 10-kilo ohm, LM709IC op-amp, In4003 diode, 12V battery, Bi-color LED.


The charging & discharging level of rechargeable batteries have a specific range. If the voltage of the battery exceeds then there is a chance to get damage. To overcome this, monitoring a battery is very important. So this battery voltage monitoring circuit is designed for indicating the battery voltage status.

Battery Voltage Monitoring with LM709 IC
Battery Voltage Monitoring with LM709 IC

This circuit is designed with an LM709IC and is designed like a comparator. In this circuit, an LED with bi-color is used like an indicator that indicates three voltage levels of the battery.

In a voltage monitor circuit, the potential driver is used with a resistor and potentiometer. Once the level of voltage increase above 13.5 V, then the IC1 output goes less consequently LED starts emitting RED color light. Likewise, once the voltage drops under a fixed level then the output will be increased. The LED starts to generate GREEN color light. Here, both the R3 & R4 resistors are used as the current limiters.

Advantages

The advantages of LM709 IC include the following.

  • High gain
  • Reduces both bias currents & offset voltage
  • Overload protection
  • No latch-up once the range of common-mode is exceeded
  • Liberty from compensation & oscillations
  • Better accuracy
  • Less noise within the circuit of high impedance
  • Fewer input currents

Applications

The applications of LM709 IC include the following.

  • This IC is used to build simple circuits like inverting amplifiers with unity gain, FET op-amp, offset balancing circuit & voltage follower.
  • Analog Electronics
  • Measuring Instruments
  • Digital Electronics
  • Mobile Chargers
  • PLCs or Programmable Logic Controllers
  • Power Supplies
  • Refrigerators
  • Desktop PC
  • Washers, Dryers
  • Motherboard
  • Voltage Comparators
  • UPS or Uninterruptible Power Supplies
  • Oscillators
  • Mathematical Operations
  • Amplifiers
  • Video Signal Conditioning Units
  • Temperature Sensors
  • Modulators
  • Processors
  • Synthesizers
  • The accusation of Sensor Data
  • Receivers
  • D/A Converters in Phone
  • Phone Chargers for Mobile
  • Error Amplifiers
  • Suitable for long interval timers or integrators
  • Sample & hold circuits
  • Waveform generators with less frequency

Thus, this is all about an overview of the LM709 IC datasheet which includes definition, pin configuration, features, circuit, advantages, and its applications. The equivalent ICs of LM709 are MC1439, LM201C & an alternative ICs of LM709 includes LM741A, LM741C, MC1439 & LM748. Here is a question for you, what are the different types of LM series ICs available in the market?

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