The HEF4028B is a 4-bit BCD to decimal decoder, a 4-bit BCO to octal decoder. It comes with an active low enable and an 8-line (Y0 to Y7) output, inverting demultiplexer. It gives best performance due to its fully buffered outputs.
When in the BCD to decimal conversion mode a 1-2-4-8 BCD code applied to inputs A0 to A3 causes the selected output to be high. The rest of the 9 outputs will become low.
When required to use it as a BCO to octal decoder, input A3 is an active LOW enable pin and outputs Y8 and Y9 are not used. When a 1-2-4 BCO code is applied to inputs, A0 to A2, it makes the selected output (Y0 to Y7) to be high. The rest of the 7 outputs will be low. And when A3 is made high the outputs (Y0 to Y7) will be forced low.
When it is used as an 8-output (Y0 to Y7) inverting demultiplexer, A0 to A2 will be used as address inputs and A3 as the data input. Outputs Y8 and Y9 will not be used.
Some important features:
• Full static operation
• Parametric rating of 5 V, 10 V, and 15
• Output characteristics are standardized symmetrical
• Operates across the temperature range -40 Cel to +85 Cel
• In accordance with JEDEC standard JESD 13-B
• Operates over a recommended VDD power supply range of 3 V to 15 V referenced to VSS (usually ground).
• Has ESD protection:
o HBM JESD22-A114E exceeds 2000 V
o MM JESD22-A115-A exceeds 200 V