HCT257 QUAD 2-CHANNEL MULTIPLEXER - ST Microelectronics
Description
M54/M74HCT257 M54/M74HCT258
HCT257 QUAD 2 CHANNEL MULTIPLEXER (3-STATE) HCT258 QUAD 2 CHANNEL MULTIPLEXER (3-STATE, INVERTING)
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HIGH SPEED tPD = 16 ns (TYP.
) at VCC = 5 V LOW POWER DISSIPATION ICC = 4 µA (MAX.
) at TA = 25 °C COMPATIBLE WITH TTL OUTPUTS VIH = 2V (MIN.
) VIL = 0.
8V (MAX) OUTPUT DRIVE CAPABILITY 15 LSTTL LOADS SYMMETRICAL OUTPUT IMPEDANCE IOH = IOL = 6 mA (MIN.
) BALANCED PROPAGATION DELAYS tPLH = tPHL PIN AND FUNCTION COMPATIBLE WITH 54/74LS257/258
B1R (Plastic Package)
F1R (Ceramic Package)
M1R (Micro Package)
C1R (Chip Carrier)
ORDER CODES : M54HCTXXXF1R M74HCTXXXM1R M74HCTXXXB1R M74HCTXXXC1R
DESCRIPTION The M54/74HCT257 and the M54/74HCT258 are high speed CMOS MULTIPLEXERs fabricated with silicon gate C2MOS technology.
They have the same high speed performance of LSTTL combined with true CMOS low power consumption.
These IC’s are composed of an independent 2channel multiplexer with common SELECT and ENABLE INPUT.
The M54/74HCT258 is an inverting multiplexer while the M54/74HCT257 is a non-inverting multiplexer.
When the ENABLE INPUT is held ”High”, outputs of both IC’s become high-impedance state.
If SELECT INPUT is held ”Low”, ”A” data is selected, when SELECT INPUT is high ”H”, ”B” data is chosen.
All inputs are equipped with protection circuits against static discharge and transient excess voltage.
This integrated circuit has input and output characteristics that are fully compatible with 54/74 LSTTL logic families.
M54/74HCT devices are designed to directly interface HSC2MOS systems with TTL and NMOS components.
They are also plug in replace-
PIN CONNECTIONS (top view) HCT257
HCT258
February 1993
1/12
M54/M74HCT257/258
INPUT AND OUTPUT EQUIVALENT CIRCUIT
CHIP CARRIER HCT257 HCT258
NC = No Internal Connection
PIN DESCRIPTION (HCT257)
PIN No 1 2, 5, 14, 11 3, 6, 13, 10 4, 7, 12, 9 15 8 16 SYMBOL SELECT 1A to 4A 1B to 4B 1Y to 4Y OE GND V CC NAME AND FUNCTION Common Data Select Input Data Input From Source A Data Input...
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