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BCD to 7-segment decoders

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74LS47N Decoder

74LS47N is a BCD to 7-Segment active-low decoder with open-collector outputs to drive indicator segments directly. The decoder accepts 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.

74ls47n_symbol

7-seg_num_representation

Function Table

 

Decimal/ Function Inputs Outputs
~LT ~RBI D C B A ~BI/RBO OA OB OC OD OE OF OG
0 H H L L L L H L(ON) L(ON) L(ON) L(ON) L(ON) L(ON) H(OFF)
1 H X L L L H H H(OFF) L(ON) L(ON) H(OFF) H(OFF) H(OFF) H(OFF)
2 H X L L H L H L(ON) L(ON) H(OFF) L(ON) L(ON) H(OFF) L(ON)
3 H X L L H H H L(ON) L(ON) L(ON) L(ON) H(OFF) H(OFF) L(ON)
4 H X L H L L H H(OFF) L(ON) L(ON) H(OFF) H(OFF) L(ON) L(ON)
5 H X L H L H H L(ON) H(OFF) L(ON) L(ON) H(OFF) L(ON) L(ON)
6 H X L H H L H H(OFF) H(OFF) L(ON) L(ON) L(ON) L(ON) L(ON)
7 H X L H H H H L(ON) L(ON) L(ON) H(OFF) H(OFF) H(OFF) H(OFF)
8 H X H L L L H L(ON) L(ON) L(ON) L(ON) L(ON) L(ON) L(ON)
9 H X H L L H H L(ON) L(ON) L(ON) H(OFF) H(OFF) L(ON) L(ON)
10 H X H L H L H H(OFF) H(OFF) H(OFF) L(ON) L(ON) H(OFF) L(ON)
11 H X H L H H H H(OFF) H(OFF) L(ON) L(ON) H(OFF) H(OFF) L(ON)
12 H X H H L L H H(OFF) L(ON) H(OFF) H(OFF) H(OFF) L(ON) L(ON)
13 H X H H L H H L(ON) H(OFF) H(OFF) L(ON) H(OFF) L(ON) L(ON)
14 H X H H H L H H(OFF) H(OFF) H(OFF) L(ON) L(ON) L(ON) L(ON)
15 H X H H H H H H(OFF) H(OFF) H(OFF) H(OFF) H(OFF) H(OFF) H(OFF)
BI X X X X X X L H(OFF) H(OFF) H(OFF) H(OFF) H(OFF) H(OFF) H(OFF)
RBI H L L L L L L H(OFF) H(OFF) H(OFF) H(OFF) H(OFF) H(OFF) H(OFF)
LT L X X X X X H L(ON) L(ON) L(ON) L(ON) L(ON) L(ON) L(ON)


H = HIGH Level
L = LOW Level
X = Don't Care
BI/RBO = Blanking input/ripple blanking output
RBI = Ripple-blanking input
LT = Lamp test
ON/OFF - state of the SSD LEDs

74LS48N Decoder

74LS48N is a BCD to 7-Segment active-high decoder with internal 2K Ohms pull-ups. The decoder accepts 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.

74ls48n_symbol

7-seg_num_representation

Function Table

Decimal/ Function Inputs Outputs
~LT ~RBI D C B A ~BI/RBO OA OB OC OD OE OF OG
0 H H L L L L H H(ON) H(ON) H(ON) H(ON) H(ON) H(ON) L(OFF)
1 H X L L L H H L(OFF) H(ON) H(ON) L(OFF) L(OFF) L(OFF) L(OFF)
2 H X L L H L H H(ON) H(ON) L(OFF) H(ON) H(ON) L(OFF) H(ON)
3 H X L L H H H H(ON) H(ON) H(ON) H(ON) L(OFF) L(OFF) H(ON)
4 H X L H L L H L(OFF) H(ON) H(ON) L(OFF) L(OFF) H(ON) H(ON)
5 H X L H L H H H(ON) L(OFF) H(ON) H(ON) L(OFF) H(ON) H(ON)
6 H X L H H L H L(OFF) L(OFF) H(ON) H(ON) H(ON) H(ON) H(ON)
7 H X L H H H H H(ON) H(ON) H(ON) L(OFF) L(OFF) L(OFF) L(OFF)
8 H X H L L L H H(ON) H(ON) H(ON) H(ON) H(ON) H(ON) H(ON)
9 H X H L L H H H(ON) H(ON) H(ON) L(OFF) L(OFF) H(ON) H(ON)
10 H H L L L L H L(OFF) L(OFF) L(OFF) H(ON) H(ON) L(OFF) H(ON)
11 H H L L L L H L(OFF) L(OFF) H(ON) H(ON) L(OFF) L(OFF) H(ON)
12 H H L L L L H L(OFF) H(ON) L(OFF) L(OFF) L(OFF) H(ON) H(ON)
13 H H L L L L H H(ON) L(OFF) L(OFF) H(ON) L(OFF) H(ON) H(ON)
14 H H L L L L H L(OFF) L(OFF) L(OFF) H(ON) H(ON) H(ON) H(ON)
15 H H L L L L H L(OFF) L(OFF) L(OFF) L(OFF) L(OFF) L(OFF) L(OFF)
BI X X X X X X L L(OFF) L(OFF) L(OFF) L(OFF) L(OFF) L(OFF) L(OFF)
RBI H L L L L L L L(OFF) L(OFF) L(OFF) L(OFF) L(OFF) L(OFF) L(OFF)
LT L X X X X X H H(ON) H(ON) H(ON) H(ON) H(ON) H(ON) H(ON)


H = HIGH Level
L = LOW Level
X = Don't Care
BI/RBO = Blanking input/ripple blanking output
RBI = Ripple-blanking input
LT = Lamp test
ON/OFF - state of the SSD LEDs

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