DDF LM3914-DIP-18

The LM3914 is a monolithic integrated circuit that senses analog voltage levels and drives 10 LEDs, providing a linear analog display. The display mode can be switched from dot to bar with a single pin. LED drive current is adjustable and programmable with no external resistors required. This feature allows the entire system to operate below 3V. The circuit contains an adjustable voltage reference and a 10-step linear voltage divider. Its low-bias-current input buffer accepts signals ranging down to ground or V-, and requires no protection against ±35V inputs. The input buffer drives 10 independent comparators referenced to the precision voltage divider, so display nonlinearity is typically held to 0.5% even over a wide temperature range. The LM3914 is designed with flexibility to easily add controllers, visual alarms, and range extension to display systems. The circuit can drive LEDs of various colors or low-current incandescent lamps. Multiple LM3914s can be "cascaded" to form displays of 20 to over 100 segments. Both ends of the voltage divider are externally accessible, allowing two drivers to be configured as a zero-center meter. The LM3914 is extremely easy to use as an analog meter circuit. A full-scale 1.2V meter requires only one resistor and a single 3V to 15V supply in addition to the 10 display LEDs. If that resistor is a potentiometer, it serves as an LED brightness control. In dot mode, there is a small amount of overlap or "fade" (approximately 1mV) between adjacent display segments. This ensures that all LEDs will not extinguish simultaneously, eliminating any display ambiguity. A variety of novel display effects can be achieved. Much of the display flexibility stems from the fact that all outputs are independent DC-regulated current sources. Various effects can be achieved by modulating these currents. Individual outputs can simultaneously drive both transistors and LEDs, enabling controller functions including "segment" control. The LM3914 can also be used as a programmer or sequencer. The LM3914 operates over a temperature range of 0°C to 70°C and is available in a DIP18 package.

• Drives LED, LCD, and vacuum fluorescent displays
• Externally selectable dot/bar display mode
• Expandable to 100-step display
• Internal reference voltage range: 1.2V ~ 12V
• Single supply operation below 3V
• Input pin groundable
• Adjustable output current range: 2mA ~ 30mA
• No multiplexing or interaction between outputs
• Input withstands ±35V without damage or false output
• Adjustable output current, open-collector
• Direct TTL or CMOS drive capability
• Internal 10-step voltage divider with floating terminals for wide adjustment range