74LS47 BCD to 7-Segment Decoder / Driver (For Common Anode) - 7447

The SN54/74LS47 are Low Power Schottky BCD to 7-Segment Decoder/Drivers consisting of NAND gates, input buffers, and seven AND-OR-INVERT gates. They offer active LOW, high sink current outputs for driving indicators directly. Seven NAND gates and one driver are connected in pairs to make BCD data and its complement available to the seven decoding AND-OR-INVERT gates. The remaining NAND gate and three input buffers provide lamp test, blanking input/ripple-blanking output, and ripple-blanking input. The DM74LS47 decodes the input data in the pattern indicated in the Truth Table and the segment identification illustration. If the input data is decimal zero, a LOW signal applied to the RBI blanks the display and causes a multi-digit display. For example, by grounding the RBI of the highest order decoder and connecting its BI/RBO to RBI of the next lowest order decoder, etc., leading zeros will be suppressed. Similarly, by grounding RBI of the lowest order decoder and connecting its BI/RBO to RBI of the next high- est order decoder, etc., trailing zeros will be suppressed. Leading and trailing zeros can be suppressed simultaneously by using external gates, i.e.: by driving RBI of intermediate decoder from an OR gate whose inputs are BI/RBO of the next highest and lowest order decoders. BI/RBO also serves as an unconditional blanking input. The internal NAND gate that generates the RBO signal has a resistive pull-up, as opposed to a totem pole, and thus BI/ RBO can be forced LOW by external means, using wired-collector logic. A LOW signal thus applied to BI/RBO turns off all segment outputs. This blanking feature can be used to control display intensity by varying the duty cycle of the blanking signal. A LOW signal applied to LT turns on all segment outputs, provided that BI/RBO is not forced LOW.

Features

• Active low outputs (for common anode LEDs or bulbs)
• Open-collector outputs
• Drive indicator segments directly
• Cascadable zero-suppression capability
• Lamp test input

Specifications

• Logic Family : LS
• Logic Type: Bipolar
• Number of Input Lines: 4
• Number of Lines (Input / Output): 4 / 7
• Propagation Delay Time: 100 ns @ 5 V
• Supply Voltage (Max): 5.25 V
• Supply Voltage (Min): 4.75 V
• Operating Temp Range : -65ºC to +150ºC
• No. of Pins: 16 Pins
• Package Type : DIP

Package Content

1 x 74LS47