SN74LS247N

The SN74LS247N is a BCD-to-7-segment Decoder/Driver electrically and functionally identical to the SN5447A/SN7447A and has the same pin assignments as their equivalents. It can be used interchangeably in present or future designs to offer designers a choice between two indicator fonts. It has full ripple-blanking input/output controls and a lamp test input. Segment identification and resultant displays are shown below. Display patterns for BCD input counts above 9 are unique symbols to authenticate input conditions. The circuit incorporates automatic leading and/or trailing-edge zero-blanking control (RBI and RBO). Lamp test (LT) of these types may be performed at any time when the BI/RBO node is at a high level. It contains an overriding blanking input (BI) which can be used to control the lamp intensity by pulsing or to inhibit the outputs. Inputs and outputs are entirely compatible for use with TTL logic outputs.

• Open-collector outputs drive indicators directly
• Lamp-test provision
• Leading/trailing zero suppression