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LM3900 Op Amp: Pinout, Datasheet, Circuits [Video&FAQ]

  • Contents

Product Overview

The LM3900 series consists of four independent, dual input, internally compensated amplifiers which were designed specifically to operate off of a single power supply voltage and to provide a large output voltage swing. These amplifiers make use of a current mirror to achieve the non-inverting input function. Application areas include ac amplifiers RC  active filters, low-frequency triangle, square wave, and pulse waveform generation circuitstachometers, and low speed, high voltage digital logic gates.

 

This blog will introduce LM3900 systematically from its features, pinout to its specifications, applications, also including LM3900 datasheet and so much more.

 

Synthchaser #107 - Homemade LM3900 Norton Op Amp Tester

 

Catalog

Product Overview

LM3900 Features

LM3900 Pinout

LM3900 Pin Configuration

LM3900 Applications

LM3900 Circuit Diagram

LM3900 Schematic and Connection Diagrams

How the 4-channel Audio Mixer Works

Specification of LM3900 VS LM2900

LM3900 Datasheet

LM3900 Manufacturer

Using Warnings

LM3900 FAQ

 

LM3900 Features

  • Wide single supply voltage  4 VDC to 32 VDC
  • Range or dual supplies g2 VDC to g16 VDC
  • Supply current drain independent of supply voltage 
  • Low input biasing current 30 nA
  • High open-loop gain  70 dB
  • Wide bandwidth 2.5 MHz (unity gain)
  • Large output voltage swing (Va b 1) Vp-p
  • Internally frequency compensated for unity gain 
  • Output short-circuit protection

 

LM3900 Pinout

The following figure is the diagram of the LM3900 pinout.

 

LM3900 Pinout

LM3900 Pinout

 

LM3900 Pin Configuration

Pin No Pin Name Description
1 NON-INV-IN 1 Non-Inverting Input 1
2 NON-INV-IN 2 Non-Inverting Input 2
3 INV-IN 2 Inverting Input 2
4 OUT 2 Output Pin 2
5 OUT 1 Output Pin 1
6 INV-IN 1 Inverting Input 1
7 GND Ground Pin
8 INV-IN 3 Inverting Input 3
9 OUT 3 Output Pin 3
10 OUT 4 Output Pin 4
11 INV-IN 4 Inverting Input 4
12 NON-INV-IN 4 Non-Inverting Input 4
13 NON-INV-IN 3 Non-Inverting Input 3
14 V+ Positive Supply Voltage

 

LM3900 Applications

  • AC amplifiers
  • RC active filters
  • Low-frequency triangle
  • Square wave
  • Pulse waveform generation circuits
  • Tachometers
  • Low speed
  • High voltage
  • Digital logic gates

 

LM3900 Circuit Diagram

Following is the circuit diagram of LM3900.

 

LM3900 Circuit Diagram

LM3900 Circuit Diagram

 

 

LM3900 Schematic and Connection Diagrams

The architecture and pin configuration of LM3900 is shown in the picture below.

 

LM3900 Schematic and Connection Diagrams

LM3900 Schematic and Connection Diagrams

 

How the 4-channel Audio Mixer Works

The amplification (gain) of each channel is controlled with 1 potentiometer. Four channels means that we will use 4 potentiometers (P1, P2, P3, P4), placed at the inverting input of each amplifier. Each potentiometer controls the audio level of each channel before amplifying the signal and performing the audio mix.

 

The potentiometers are used to control the volume of the input signals. The outputs of the 4 channels are mixed after passing through 4 resistors of the same value (R11, R12, R13, R14)

 

All operational amplifiers are configured as inverting amplifiers and have decoupling capacitors at their inputs and outputs. These capacitors filter (block) the direct current component of the signals at the input and output, amplifying only the alternating signal (the audio signal).

 

Specification of LM3900 VS LM2900

key LM3900 LM2900
Number of Channels (#) 4 4
Total Supply Voltage (Min) (+5V=5, +/-5V=10) 4.5 4.5
Total Supply Voltage (Max) (+5V=5, +/-5V=10) 32 32
GBW (Typ) (MHz) 2.5 2.5
Slew Rate (Typ) (V/us) 20 20
Rail-to-Rail No No
Iq per channel (Typ) (mA) 1.55 1.3
Rating Catalog Catalog
Operating Temperature Range (C) 0 to 70 -40 to 85
Package Group SOIC PDIP PDIP SOIC
Approx. Price (US$) 0.08 | 1ku 0.09 | 1ku
Package Size: mm2:W x L (PKG) See datasheet (PDIP) See datasheet (PDIP)
Additional Features N/A N/A
Input Bias Current (Max) (pA) 200000 200000
Output Current (Typ) (mA) 10 5
Architecture Bipolar Bipolar

 

LM3900 Datasheet

You can download this datasheet for LM3900 Quad Amplifier – Datasheet from the link given below:

 

LM3900 Datasheet

 

LM3900 Manufacturer

Texas Instruments Incorporated (TI) is a global semiconductor design and manufacturing company that develops analog ICs and embedded processors. By employing the world's brightest minds, TI creates innovations that shape the future of technology. TI is helping more than 100,000 customers transform the future, today.

 

Using Warnings

Note: Please check their parameters and pin configuration before replacing them in your circuit.

 

LM3900 FAQ

① What are the cool things about the LM3900?

One of the cool things about the LM3900 is that the input voltage can exceed the supply rails without a lot of fancy stuff. Thus you could look for the presence of line to speaker levels very easily and even filter the hiss. That's what a specific timer of mine does.

 

② How many channels does a lm3900 audio mixer have?

The circuit has two channels for microphone inputs and two channels for inputs of other devices. If you want a mixer with more input channels, you can duplicate this circuit and get a mixer with up to 8 channels. The LM3900 operational amplifiers have the following characteristics: High amplitude output voltage.

 

③ Can a lm3900 op amp be replaced?

The LM3900 was a very different kind of op amp. It operates on the difference in input current rather than the difference in input voltages. It can not be replaced with a LM324 op amp. From what I read, the NTE992 is a replacement.

 

④ What do LM3900 amplifiers use to achieve the non-inverting input function?

Current mirror

 

⑤ What type of filter is used in the LM3900 series?

RC active filters

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