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SN54/74LS47
BCD TO 7-SEGMENT
DECODER/DRIVER
The SN54 / 74LS47 are Low Power Schottky BCD to 7-Segment Decod-
er / Drivers consisting of NAND gates, input buffers and seven AND-OR-IN-
VERT gates. They offer active LOW, high sink current outputs for driving BCD TO 7-SEGMENT
indicators directly. Seven NAND gates and one driver are connected in pairs DECODER/ DRIVER
to make BCD data and its complement available to the seven decoding
AND-OR-INVERT gates. The remaining NAND gate and three input buffers LOW POWER SCHOTTKY
provide lamp test, blanking input / ripple-blanking output and ripple-blanking
input.
The circuits accept 4-bit binary-coded-decimal (BCD) and, depending on
the state of the auxiliary inputs, decodes this data to drive a 7-segment display
indicator. The relative positive-logic output levels, as well as conditions
required at the auxiliary inputs, are shown in the truth tables. Output J SUFFIX
configurations of the SN54 / 74LS47 are designed to withstand the relatively CERAMIC
high voltages required for 7-segment indicators. CASE 620-09
These outputs will withstand 15 V with a maximum reverse current of 16
1
250