3至8线译码器（反相） 3 TO 8 LINE DECODER INVERTING
DESCRIPTION
The 74ACT138 is an advanced high-speed CMOS 3 TO 8 LINE DECODER INVERTING fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS tecnology.
If the device is enabled, 3 binary select inputs A, B, and C determine which one of the outputs will go low. If enable input G1 is held low or either G2A or G2B is held high, the decoding function is inhibited and all the 8 outputs go to high.
Three enable inputs are provided to ease cascade connection and application of address decoders for memory systems.
■ HIGH SPEED: tPD = 5ns TYP. at VCC = 5V
■ LOW POWER DISSIPATION:
ICC = 4µAMAX. at TA=25°C
■ COMPATIBLE WITH TTL OUTPUTS
VIH = 2V MIN., VIL = 0.8V MAX.
■ 50Ω TRANSMISSION LINE DRIVING CAPABILITY
■ SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 24mA MIN
■ BALANCED PROPAGATION DELAYS:
tPLH = tPHL
■ OPERATING VOLTAGE RANGE:
VCC OPR = 4.5V to 5.5V
■ PIN AND FUNCTION COMPATIBLE WITH 74 SERIES 138
■ IMPROVED LATCH-UP IMMUNITY