Part Number: LM3915N-1

Manufacturer: Texas Instruments


Shipped from: Shenzhen/HK Warehouse

Stock Available: Check with us

Technical Specifications of LM3915N-1

Datasheet  LM3915N-1 datasheet
Category Integrated Circuits (ICs)
Family PMIC – Display Drivers
Manufacturer Texas Instruments
Packaging Tube
Part Status Last Time Buy
Display Type LED, LCD, Vacuum Fluorescent (VF)
Configuration Dot/Bar Display
Digits or Characters 10 Steps
Current – Supply 6.1mA
Voltage – Supply 3 V ~ 25 V
Operating Temperature 0°C ~ 70°C
Mounting Type Through Hole
Package / Case 18-DIP (0.300″, 7.62mm)
Supplier Device Package 18-DIP

LM3915N-1 Introduction

The LM3915N-1 is a very flexible single-chip integrated circuit that was made to measure analogue voltage levels and power different kinds of screens, such as LEDs, LCDs, and vacuum fluorescent displays. This powerful IC has an analogue display with a logarithmic 3 dB/step scale, which makes it easy to see how voltage levels change. It also has the special ability to switch between a bar graph display mode and a moving dot display mode. In this guide, we’ll talk about how the LM3915N-1 works, what it can be used for, and how it works. This will give you a full idea of this great analogue display driver.

Overview of LM3915N-1

The LM3915N-1 is an important part of many electronic systems that need to watch analogue voltage and show it visually. This integrated circuit has a lot of features and functions that make it a good choice for many different uses. In this guide, we’ll talk about the LM3915N-1’s different features and how they can help your projects.

Circuit Operation

The LM3915N-1 works because it has a complex circuitry inside that can correctly measure analogue voltage levels and show them on a screen. In this part, we’ll give you a high-level look at how the LM3915N-1 works on the inside. We’ll talk about how it senses voltage and the benefits of its logarithmic 3 dB/step analogue display.

  • The LM3915N-1’s internal logic is made up of several key parts that work together to do their jobs. A voltage reference, comparators, a voltage divider network, and output drivers are some of these parts.
  • Voltage Sensing Mechanism: The input pins of the LM3915N-1 are hooked up to a voltage divider network. This voltage divider network is made up of resistors that are linked together like rungs on a ladder. The analogue voltage to be watched is connected to the input pins, and the voltage divider network splits this voltage into multiple voltage segments.
  • Comparators: The LM3915N-1 has a set of comparators that compare each of the voltage segments to a reference voltage. Each comparator compares its own voltage segment to the standard voltage, and based on the result, it sends out a digital signal.
  • 3 dB per step logarithmic Analogue monitor: The LM3915N-1 is made to have a 3 dB/step logarithmic analogue monitor. This means that each step or part of the display shows an increase of 3 decibels in the input voltage level. The logarithmic scale shows voltage levels in a way that is easier to understand. This is especially helpful when working with a wide range of voltages.

Benefits of the logarithmic display characteristic

  • Enhanced Sensitivity: The LM3915N-1’s logarithmic scale makes it more sensitive to changes in voltage levels at lower values. This means that smaller changes in voltage can be shown with more detail and accuracy.
  • Visual Perception: The logarithmic scale is more like how people judge the strength of sounds or lights. Because of this, the LM3915N-1 is a good choice for audio applications because it can properly show how loud or intense a sound is.
  • Display Range Adaptability: The LM3915N-1 can be used with a wide range of power levels because it has a logarithmic display. By changing the standard voltage and the voltage divider network, the display can be made to work with a wide range of voltages without losing accuracy or resolution.

By using the voltage sensing mechanism and the logarithmic 3 dB/step analogue display, the LM3915N-1 shows analogue voltage levels on the connected display in a way that is clear and easy to understand. This makes it easy for users to keep track of and understand the voltage information.

Note: The LM3915N-1’s detailed internal circuitry may contain technicalities that are hard to understand. For a deeper understanding, it is best to look at the datasheet and any other tools that the manufacturer provides.

External Components and Connections

For the LM3915N-1 to work well and connect to a monitor (LED, LCD, or vacuum fluorescent), it needs certain external parts. A power source, a voltage reference, resistors, and capacitors are all examples of these. The voltage range should be right for the power source. In the voltage divider network, the resistors are used to set the voltage levels for each section. For decoupling and steadiness, you need capacitors.

For LED screens, connect each of the LM3915N-1’s output pins to a separate LED using current-limiting resistors. LCD screens need an extra driver circuit, and the links depend on the type of driver circuit. LEDs and vacuum fluorescent displays both work by connecting the anodes of the display pieces to the outputs of an LM3915N-1.

Check the LM3915N-1 documentation for suggestions on which parts to choose. Choose the numbers of the resistors based on the voltage range and resolution you want. The capacitance and voltage values of capacitors should be right.

By following these rules and making the right connections, you can make sure that the LM3915N-1 and the chosen display type work well together.

Application Examples

The LM3915N-1 is often used in many different ways. Here are some examples:

Audio Level Indicator

  • Connect an audio output to the input pins of the LM3915N-1.
  • Connect the LM3915N-1 outputs to a bar graph LED display using a voltage divider network.
  • Benefits: The audio levels are shown accurately, which makes it easier to watch and make changes.

Battery Charge Monitor

  • Connect the battery voltage to the input pins of the LM3915N-1.
  • Connect the LM3915N-1 outputs to a bar graph LED display using a voltage divider network.
  • Benefits: It’s easy to see how full the battery is, so you can charge it or replace it when you need to.

RF Signal Strength Indicator

  • Connect the voltage of the RF signal strength to the input pins of the LM3915N-1.
  • Connect the LM3915N-1 outputs to a bar graph LED display using a voltage divider network.
  • Benefits: Accurately measuring signal strength, which helps with antenna placement and optimisation.

Spectrum Analyzer

  • Connect the output of the audio spectrum analyzer to the input pins of the LM3915N-1.
  • Connect the LM3915N-1 outputs to a bar graph LED display using a voltage divider network.
  • Benefits: It shows how the frequencies are spread out visually, which makes it easier to understand audio signals.

VU Meter

  • Connect an audio output to the input pins of the LM3915N-1.
  • Connect the LM3915N-1 outputs to a moving dot LED show using a voltage divider network.
  • Benefits: It has a dynamic display that looks like traditional VU metres, which makes it easier to watch and mix audio.

In these situations, the LM3915N-1 has reliable voltage sensing, a logarithmic display, and different ways to show the voltage. It is easy to use and shows voltage accurately, making it a great choice for tracking and displaying analogue voltage.


The LM3915N-1 is a great analogue display driver because it can switch and show a logarithmic 3 dB/step display. It can accurately measure voltage and work with different kinds of displays, making it a very flexible tool. The LM3915N-1 is a trusted tool for analogue voltage display needs. It can be used in audio systems, battery monitors, RF communication, and visualizers, among other things.

We suggest getting in touch with our experts at ICRFQ to learn more about the LM3915N-1 and get personalised advice. They will help you get the most out of the LM3915N-1 and help you get the best results for your particular purpose.

4.8/5 - (397 votes)
Kevin Chen