Overview
The LM3914VX/NOPB, produced by Texas Instruments, is a monolithic integrated circuit designed to sense analog voltage levels and drive 10 LEDs, providing a linear analog display. This IC is versatile and can be used in various display modes, including bar and dot displays, which can be selected externally by the user. It operates with a single supply voltage of less than 3V and can drive LEDs, LCDs, or vacuum fluorescent displays. The LM3914 features an internal adjustable reference and a precise 10-step voltage divider, making it suitable for a wide range of applications, including analog meter circuits, visual alarms, and expanded scale functions.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Operating Temperature Range | 0 | 70 | °C | |
| Supply Voltage | 25 | V | ||
| Input Signal Overvoltage | ±35 | V | ||
| Output Current Programmable | 2 | 30 | mA | |
| Internal Voltage Reference | 1.2 | 1.28 | 1.34 | V |
| Standby Supply Current | 2.4 | 4.2 | mA | |
| Power Dissipation (PDIP) | 1365 | mW |
Key Features
- Drives LEDs, LCDs, or vacuum fluorescent displays.
- Bar or dot display mode externally selectable by the user.
- Expandable to displays of 100 steps by chaining multiple LM3914s.
- Internal voltage reference from 1.2V to 12V.
- Operates with a single supply of less than 3V.
- Inputs operate down to ground and withstand ±35V without damage or false outputs.
- Output current programmable from 2 mA to 30 mA.
- No multiplex switching or interaction between outputs.
- LED driver outputs are current-regulated, open-collectors.
- Outputs can interface with TTL or CMOS logic.
- The internal 10-step divider is floating and can be referenced to a wide range of voltages.
Applications
The LM3914 is highly versatile and can be applied in various scenarios, including:
- Analog meter circuits: It can be used to create simple and accurate analog meters with minimal external components.
- Visual alarms: The IC can be configured to provide visual alerts based on analog voltage levels.
- Expanded scale functions: Multiple LM3914s can be chained to create displays with up to 100 segments.
- Controller and sequencer functions: The IC can act as a programmer or sequencer, controlling other devices based on analog inputs.
- Display systems: It can drive LEDs of many colors or low-current incandescent lamps, making it suitable for various display applications.
Q & A
- What is the primary function of the LM3914?
The LM3914 senses analog voltage levels and drives 10 LEDs to provide a linear analog display.
- How can the display mode be selected on the LM3914?
The display mode can be selected externally by the user, switching between bar and dot modes using a single pin.
- What is the operating temperature range of the LM3914?
The LM3914 operates from 0°C to +70°C.
- Can the LM3914 operate with a single supply voltage?
Yes, the LM3914 can operate with a single supply voltage of less than 3V.
- How can multiple LM3914s be used together?
Multiple LM3914s can be chained to form displays of up to 100 segments.
- What types of displays can the LM3914 drive?
The LM3914 can drive LEDs, LCDs, or vacuum fluorescent displays.
- How is the output current of the LM3914 regulated?
The output current is regulated and programmable from 2 mA to 30 mA, eliminating the need for external resistors.
- Can the LM3914 interface with TTL or CMOS logic?
Yes, the outputs of the LM3914 can interface with TTL or CMOS logic.
- What is the internal voltage reference range of the LM3914?
The internal voltage reference range is from 1.2V to 12V.
- How does the LM3914 handle input signals near ground or high voltages?
The LM3914's input buffer accepts signals down to ground and withstands ±35V without damage or false outputs.
