1-of-n decoder A 1-of-n binary decoder has n output bits. This type of decoder asserts exactly one of its n output bits, or none of them, for every integer input value. The "address" (bit number) of the activated output is specified by the integer input value. For example, output bit number 0 is selected when the integer value 0 is applied to the inputs. Examples of this type of decoder include: • A
3-to-8 line decoder activates one of eight output bits for each input value from 0 to 7 — the range of integer values that can be expressed in three bits. Similarly, a
4-to-16 line decoder activates one of 16 outputs for each 4-bit input in the integer range [0,15]. • A
BCD to decimal decoder has ten output bits. It accepts an input value consisting of a
binary-coded decimal integer value and activates one specific, unique output for every input value in the range [0,9]. All outputs are held inactive when a non-decimal value is applied to the inputs. • A
demultiplexer is a 1-of-n binary decoder that is used to route a data bit to one of its n outputs while all other outputs remain inactive.
Code translator Code translators differ from 1-of-n decoders in that multiple output bits may be active at the same time. An example of this is a
seven-segment decoder, which converts an integer into the combination of segment control signals needed to display the integer's value on a
seven-segment display digit. One variant of seven-segment decoder is the
BCD to seven-segment decoder, which translates a binary-coded decimal value into the corresponding segment control signals for input integer values 0 to 9. This decoder function is available in standard ICs such as the CMOS
4511.
Binary to Unary Decoder A binary to unary decoder converts each binary value to its associated
unary representation, in which multiple output bits may be asserted. These decoders can be used in
DACs where each bit is equally weighted, and circuits that require a binary
mask or window. ==See also==