XR-2279 Datasheet | Exar

XR- 2279 Dot and Bar-Graph Display Generators GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM The XR-2279 is a 12 point logarithmic dot or bar-graph generator/LED driver_ The device pares an input signal with an adjustable reference and graphically displays the results_ Since LED driving current is provided by on board adjustable current sources, no current lim- iting resistors are required. A special feature of the XR2279 is the four highest outputs sink one half the current of the lower eight; this allows equivalent brightness with red and green mixed displays. Dot or bar mode selection is provided. The twelve out- put levels are in 3 dB steps from - 27 dB to + 6 dB. The reference...