DESCRIPTION
The 74ACT257 is an advanced high-speed CMOS QUAD 2-CHANNEL MULTIPLEXER (3-STATE) fabricated with sub-micron silicon gate and double-layer metal wiring C2MOS tecnology. It is composed of an independent 2-channel multiplexer with common SELECT and ENABLE (OE)inputs. It is a non-inverting multiplexer. When the ENABLE input is held HIGH, the outputs are forced to a high impedance state. When the SELECT input is held LOW, "A" data is selected; when SELECT input is held HIGH, "B" data is selected.

■ HIGH SPEED: tPD = 5 ns (TYP.) at VCC = 5V
■ LOW POWER DISSIPATION: ICC = 4 µA(MAX.) 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 257
■ IMPROVED LATCH-UP IMMUNITY