NTE1549

The NTE1549 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs, LCDs, or vacuum fluorescent displays, providing an  lectronic version of the popular VU meter. 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 of NTE1549 can operate from a single supply as low 3V or as high as 25V.

This NTE1549 contains an adjustable voltage reference and an accurate tenstep voltage divider. The high impedance input buffer accepts signals down to ground and up to within 1.5V of the positive supply. Further, NTE1549 needs no protection against inputs of ±35V. The input buffer drives 10 individual comparators
referenced to the precision divider. Accuracy of NTE1549 is typically better than 0.2dB.

Audio applications of NTE1549  include average or peak level indicators, and power meters. Replacing conventional meters with an LED bar graph results in a faster  esponding, more rugged display with high visibility that retains the ease of interpretation of an analog display.

The NTE1549 is extremely easy to apply. A 12V fullscale meter requires only one resistor in addition to the ten LEDs. One more resistor program in addition to the fullscale anywhere from 1.2V to 12V independent of supply voltage. LED brightness of NTE1549 is easily controlled with a single pot.

The NTE1549 is very versatile. The outputs can drive LCDs, vacuum fluorescents and incandescent bulb as well as LEDs of any color. Multiple devices can be cascaded for a dot or bar mode display for increased range and/or resolution.