HD74HCT138

HD74HCT138 3-to-8-line Decoder/Demultiplexer Description The HD74HCT138 has 3 binary select inputs (A, B, and C). If the device is enabled these inputs determine which one of the eight normally high outputs will go low. Two active low and one active high enables (G1, G2A and G2B) are provided to ease the cascading of decoders. Features LSTTL Output Logic Level Compatibility as well as CMOS Output Compatibility High Speed Operation: tpd (A, B, C to Y) = 18.5 ns typ (CL = 50 pF) High Output Current: Fanout of 10 LSTTL Loads Wide Operating Voltage: VCC = 4.5 to 5.5 V Low Input Current: 1 µA max Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C) HD74HCT138 Function Table Inputs Enable G1 X X L H H H H H H H H G2A X H X L L L L L L L L G2B H X X L L L L L L L L Select C X X X L L L L H H H H B X X X L L H H L L H H A X X X L H L H L H L H Outputs Y0 H H H L H H H H H H H Y1 H H H H L H H H H H H Y2 H H H H H L H H H H H Y3 H H H H H H L H H H H Y4 H H H H H H H L H H H Y5 H H H H H H H H L H H Y6 H H H H H H H H H L H Y7 H H H H H H H H H H L Pin Arrangement A Select Inputs B C G2A Enable Inputs G2B G1 Outputs Y7 GND 1 2 3 4 5 6 7 8 (Top view) B C G2A G2B G1 Y7 A Y0 Y1 Y2 Y3 Y4 Y5 16 VCC 15 Y0 14 Y1 13 Y2 12 Y3 11 Y4 10 Y5 9 Y6 Outputs Y6 2 HD74HCT138 DC Characteristics Ta = 25°C Item Input voltage Symbol VIH VIL Output voltage VOH Ta = –40 to +85°C Max — 0.8 — — 0.1 0.33 ±1.0 40 µA µA V Unit V V V Test Conditions VCC (V) 4.5 to 5.5 4.5 to 5.5 ...