XR-2278

XR·2277/2278 Dot and Bar Graph Display Generators GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM The XR-2277 and XR-2278 are 12 point level detector circuits designed for direct interfacing to light emitting diode (LED) moving-dot or bar-graph displays. Each of the circuits is comprised of an input buffer amplifier and 12 comparators, biased from a resistor string at logarithmic intervals. Accuracy is enhanced by an internal reference. Each comparator provides a high impedance current source output which are all very closely matched and simultaneously adjustable with a single external resistor. A control signal applied to the mode select pin determines whether the display is driven in a moving-dot or bar-graph format. FEATURES High Impedance Buffered Input Direct LED Interface Constant Current Outputs External Dot/Bar Mode Select ORDERING INFORMATION Part Number XR-2277P XR-2278P Package Plastic Plastic Operating Temperature o·e to + 70·e o·e to + 70·e APPLICATIONS Bar-Gra...