top of page


                     74LS47             BCD TO 7 SEGMENT DECODER DRIVER           POSITIVE LOGIC    



(Low = on, 40mA, 30-Volt Outputs)

This package accepts a 1-2-4-8 positive-logic Binary Coded Decimal (BCD) input and converts it to the proper pattern necessary to illuminate a 7 segment display. A low output is intended to light the segment. (Common anode).

The outputs can sink 40milliamperes (mA) in the low state and can withstand 30 volts in the high state. The supply voltage must remain at 5+ volts. An output-high state can be obtained only if a display device or resistor pulls the output to some positive voltage less than 30 volts.

Current-liminting resistors, typically 330 ohms, must be used when driving a light emitting diode display with this package. Incandescent or fluorescent readouts can be driven directly.

The Lam test input should remain high when not in use. To enable the lamp test feature, momentarily bring the Lamp Test input to ground, this will illuminate all of the segment outputs (for testing). A low on the blanking input will extinguish character "0". A low on the Blanking output is provided to extinguish the character "0" of the next stage if leading-edge blanking is desired.

A low on the Blanking output will extinguish the display.

Propagation delay = 45 nanoseconds
Current per Package = 43 milliamperes (mA)


bottom of page