XR-2279

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 compares 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 point is externally adjustable. FEATURES Direct LED Interface Constant Three dB/Step Logarithmic Scale External Dot/Bar Mode Select for Dot/Bar-Graph Formats Adjustable Output Current Levels Current Source Outputs APPLICATIONS Bar Graph Display Generator Moving-dot Display Generator Logarithmic Level...