The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs, LCDs, or vacuum fluorescent displays, providing a logarithmic 3 dB/step analog display. One pin changes the display from a bar graph to a moving dot display. LED current drive is regulated and programmable, eliminating the need for current limiting resistors. The whole display system can operate from a single supply as low as 3V or as high as 25V. The IC contains an adjustable voltage reference and an accurate ten-step voltage divider.
The input buffer drives 10 individual comparators referenced to the precision divider. Accuracy is typically better than 1 dB. The LM3915’s 3 dB/step display is suited for signals with a wide dynamic range, such as audio level, power, light intensity, or vibration. Audio applications include average or peak level indicators, power meters, and RF signal strength meters. Replacing conventional meters with an LED bar graph results in a faster responding, more rugged display with high visibility that retains the ease of interpretation of an analog display. The LM3915 is extremely easy to apply.
LM3915 Pinout
LM3915 Pin Configuration
| Pin No | Pin Name | Description |
|---|---|---|
| 1 | LED NO 1 | Led No 1 |
| 2 | V- | -ve Voltage Pin |
| 3 | V+ | +ve Voltage Pin |
| 4 | DIVIDER (LOW END) | Divider (Low End) |
| 5 | SIGNAL INPUT | Signal Input Pin |
| 6 | DIVIDER (HIGH END) | Divider(High End) |
| 7 | REFERENCE OUTPUT | Reference Output Pin |
| 8 | REFERENCE ADJUST | Reference Adjust Pin |
| 9 | MODE SELECT | Mode Select Pin |
| 10 | LED NO. 10 | Led No 10 Pin |
| 11 | LED NO. 9 | Led No 9 Pin |
| 12 | LED NO. 8 | Led No 8 Pin |
| 13 | LED NO. 7 | Led No 7 Pin |
| 14 | LED NO. 6 | Led No 6 Pin |
| 15 | LED NO. 5 | Led No 5 Pin |
| 16 | LED NO. 4 | Led No 4 Pin |
| 17 | LED NO. 3 | Led No 3 Pin |
| 18 | LED NO. 2 | Led No 2 Pin |
LM3915 Features
- Bar or dot display mode externally selectable by user
- Expandable to displays of 90 dB
- Internal voltage reference from 1.2V to 12V
- Operates with single supply of 3V to 25V
- Inputs operate down to ground
- Output current programmable from 1 mA to 30 mA
- Input withstands ±35V without damage or false outputs
- Outputs are current regulated, open collectors
- Directly drives TTL or CMOS
- The internal 10-step divider is floating and can be referenced to a wide range of voltages
Application
- Audio level application such as average or peak level indicators, power meters and RF signal strength meters
- Industrial Power Tool
- Light intensity or Vibration
You can download this datasheet for LM3915 3dB Steps Bar-Graph Display Driver – Datasheet from the link given below:
