on November 14th 73

LM3915 Dot/Bar Display Driver: Pinout, Circuit, and Datasheet

The LM3915 LED display driver, adeptly translates fluctuating audio signals into a visual format, enriching our understanding and interaction with sound. In this article, we delve into the LM3915’s functionalities, specifications, and applications.

Catalog

What is the LM3915?

The LM3915 integrated circuit skillfully transforms analog voltage levels into a visually engaging format spread over ten individual segments. These segments can be realized through LEDs, LCDs, or vacuum fluorescent displays, each step embodying a 3 dB increment for a logarithmic interpretation. This feature invites an intuitive grasp of rapid changes in audio, lighting, or power scenarios. A feature that stands out is the option for a bar graph or dot mode display, easily toggled with a single pin, showing the device’s flexibility in matching diverse preferences. Showcasing elevated adaptability, the LM3915 facilitates adjustable LED brightness without needing current-limiting resistors, functioning effectively over a power supply range from 3V to 25V. Its interior structure houses a precise voltage reference and a ten-step voltage divider, crafting a measurement accuracy that maintains less than a 1 dB deviation. This careful exactness satisfies applications demanding fine signal portrayal. Displaying a simplicity in design, the LM3915 operates with minimal additional components; a single resistor sets the full-scale voltage span from 1.2V to 12V, unaffected by power supply shifts.

LM3915 Pin Configuration

LM3915 Symbol, Footprint, and CAD Model

Features of the LM3915

• Displays 30 dB range in 3 dB steps.

• Supports bar and dot display modes.

• Operates on 3V to 25V single power supply.

• Internal voltage reference from 1.2V to 12V.

• Tolerates input voltages up to ±35V.

• Programmable current from 1mA to 30mA.

• Temperature range: 0°C to 70°C.

• High precision and stability for accurate measurements.

LM3915 Technical Specifications

Technical characteristics, properties, and parameters of the LM3915, including components with specifications comparable to the Texas Instruments LM3915N-1.

Type	Parameter
Mount	Through Hole
Mounting Type	Through Hole
Package / Case	18-DIP (0.300, 7.62mm)
Number of Pins	18
Operating Temperature	0°C~70°C
Packaging	Tube
JESD-609 Code	e0
Pbfree Code	no
Part Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Number of Terminations	18
ECCN Code	EAR99
Terminal Finish	Tin/Lead (Sn/Pb)
Additional Feature	SELECTABLE DOT MODE
Max Power Dissipation	1.365W
Voltage - Supply	3V~25V
Terminal Position	DUAL
Number of Functions	1
Terminal Pitch	2.54mm
Base Part Number	LM3915
Pin Count	18
Number of Outputs	10
Output Voltage	1.28V
Configuration	Dot/Bar Display
Number of Circuits	1
Operating Supply Current	6.1mA
Nominal Supply Current	9.2mA
Output Current	30mA
Power Dissipation	1.365W
Max Supply Current	9.2mA
Max Output Voltage	1.34V
Min Input Voltage	3V
Max Input Voltage	25V
Display Type	LED, LCD, Vacuum Fluorescent (VF)
Interface IC Type	LED DISPLAY DRIVER
Number of Segments	10
Multiplexed Display Capability	NO
Display Mode	BAR GRAPH
Digits or Characters	10 Steps
Height	3.3mm
Length	22.86mm
Width	6.35mm
REACH SVHC	No SVHC
Radiation Hardening	No
RoHS Status	Non-RoHS Compliant

Block Diagram of the LM3915

Implementing the LM3915 for LED Displays

The inherent simplicity of the LM3915 makes it an attractive option for signal visualization endeavors. It requires only a few external elements, such as LEDs and resistors, simplifying its integration. In the audio signal representation, accurately setting reference voltages holds importance. For instance, with a peak audio voltage of 3.6V, adjusting RHI and REF OUT to match this level, while keeping RLO at 0V, is a precise setup that maintains equilibrium and ensures trustworthy signal monitoring. The ability to modify LED current and reference voltages presents with plentiful possibilities. Such adaptability enables customization to meet diverse display needs without facing burdensome engineering constraints. Adjusting current settings permits optimal brightness for varying lighting conditions, enhancing engagement. By judiciously fine-tuning these parameters, designs achieve precision and reliability, marked by seamless innovation tailored to distinct requirements.

Circuit with the LM3915

Applications of the LM3915

Audio Visualization

Audio visualization represents one of the most prominent fields where the LM3915 is employed. By shifting audio signals into visual forms, it offers an engaging way to monitor sound intensity and frequency spread. In practical scenarios, this involves incorporating the LM3915 into VU meters and visual equalizers. Such equipment proves highly beneficial during live performances, as audio feedback can dramatically enrich sound quality. With its dynamic response capabilities, the LM3915 adjusts display bars in sync with input signals, thereby enabling detailed management of audio parameters.

Battery Level Indication

The LM3915 excels in delivering definitive and trustworthy indications of battery levels. This is advantageous in portable devices where knowing the battery status bears implications. Visualizing battery charge via a series of LEDs grants quick and clear insights into battery condition. Such an arrangement mirrors battery monitoring systems used in demanding contexts, like navigational equipment, where staying aware of power reserves holds considerable weight.

Economical Monitoring Instruments

One notable application of the LM3915 is the development of cost-effective monitoring tools. Leveraging its scalable display capabilities allows the construction of varied monitoring systems, useful for measuring parameters such as temperature, electrical load, or ambient light. Its flexibility supports integration into multifunctional devices, delivering effective solutions without substantial investment. In environmental monitoring, the LM3915 can be tailored to reflect shifts in conditions, serving as a visual alert mechanism in settings like laboratories or greenhouses.

Mechanical Data of LM3915

Manufacturer Information

Texas Instruments (TI), the creative force behind the LM3915, has carved a niche for itself in the vast realm of global technology. Specializing in semiconductors and circuits, TI focuses intently on embedded processing chips. This dedication reflects their pursuit of breakthroughs in chip technology, shaping the backbone of modern industries as they navigate the shifting landscapes of technological evolution with skill and foresight. TI embeds a spirit of endless creativity at the heart of its operations. This drive propels the design of groundbreaking semiconductor technologies, and guides shrewd strategic investments in research and development. Such endeavors have cultivated a wealth of patents, underscoring TI's prowess in spearheading developments while safeguarding the intellectual property that fuels its competitive stature. Texas Instruments demonstrates how leveraging deep-rooted in semiconductor technology can drive innovation with far-reaching global effects. By prioritizing sustainable progress through innovation and strategic acumen, TI maintains its prominence and leadership in a rapidly evolving industry, illuminating the path for future developments in technology and electronics.

Datasheet PDF

LM3915N-1 Datasheets:

Cylindrical Battery Holders.pdf