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LM3916 Dot/Bar Display Driver

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LM3916 is a monolithic integrated circuit that senses analog voltage level especially audio signals and drives 10 LED’s either in dot mode or in bargraph mode. This is a versatile IC. Multiple IC’s can be cascaded to drive more than 10 LED’s for higher resolution. The most popular application of the LM3916 is VU meter. The IC is available as DIP package from the manufacturers.

 

Pin Description:

PIN NO

PIN NAME

PIN DESCRIPTION

1, 10 to 18

LED Outputs

Connect LED’s negative leg to these pins.

2

V-

Connect this pin to ground.

3

V+

Connect this pin to positive supply.

4

RLO

Low voltage reference pin.

5

SIG

Signal input to this pin.

6

RHI

High voltage reference pin.

7

REF OUT

Internal voltage reference output pin.

8

REF ADJ

Internal voltage reference adjust pin.

9

MODE

Mode choosing pin for either Dot or Bar mode.

 

Features of LM3916:

  • Wide input voltage range: Vin = 3V to 25V.
  • Externally selectable dot or bar mode.
  • Programmable output current from 1mA to 30mA.
  • Directly drives TTL and CMOS loads.
  • Internal LED driver.

Note: More technical details can be found at the LM3916 datasheet linked at the bottom of this page.

 

Alternatives for LM3916: LM3914 and LM3915.

LM3916 Replacement: NTE1549.

 

How to use LM3916:

As said earlier, the LM3916 drives 10 LED’s with respect to analog input signal. The LED’s can be driven as either dot mode or bar mode by connecting to positive supply or left floating. The basic LM3916 circuit is given below.

Basic Circuit of LM3916 Dot/Bar Display Driver

 

The current through the LED and the reference voltage can be programmed using voltage divider resistors on pin 7 of the IC.

Basic Circuit of LM3916 Dot/Bar Display Driver

 

The value of the resistors can be calculated using the formula,

Vout = VRef(1+ R2R1) + IAdjR2

 

Dot Mode and Bar Mode:

The mode pin can be used to drive the LEDs in either dot or bar mode. In dot mode, only one LED is lit at a time. In bar mode, The LED starts lit from the lowest led (starts from pin1) to the top LED according to the input signal. To use the IC in bar mode, connect the mode pin (pin  9) directly to pin 3 of LM3916. If the pin 9 open left, the IC is in dot mode.

 

2D Model:

2D Model of LM3916 Dot/Bar Display Driver

Component Datasheet

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