CD 4511 The CD 4511 is a BCD to 7-Segment latch / decoder / driver. Its function is to convert the logic states at the outputs of a BCD, or binary coded decimal, counter like the 4510 into signals which will drive a 7-segment display. The display shows the decimal numbers 0-9 and is easily understood. The LT (lamp test) turns on all segments to test the display. BL (blanking) turns off the display or intensity-modulates it. LE stores or "freezes" the display. A0 to A3 are BCD input data from CD 4510.

The CD 4511 is a CMOS chip. Minimum supply voltage 6v Maximum supply voltage 15v Max current per output 15mA Maximum speed of operation 5MHz

There are two important types of 7-segment LED display. In a common cathode display, the cathodes of all the LEDs are joined together and the individual segments are illuminated by HIGH voltages. In a common anode display, the anodes of all the LEDs are joined together and the individual segments are illuminated by connecting to a LOW voltage. The 4511 is designed to drive a common cathode display and won't work with a common anode display. You need to check that you are using the right kind of display before you start building. The 0.56 in. 7-segment display common cathode available from Rapid works well as part of a prototype board circuit. When the 4511 is set up correctly, the outputs follow this truth table: There is a question about whether the 6's and 9's should have tails. The 4511 produces a display without tails. If other binary values, greater than 1 0 0 1, are connected to the inputs of the 4511, the outputs are all 0's and the display is blank.