74VHCT257A
QUAD 2 CHANNEL MULTIPLEXER (3-STATE)
PRELIMINARY DATA
March 2000
n HIGH SPEED: tPD = 5.8 ns (TYP.) at VCC =5V
n LOWPOWER DISSIPATION:
ICC =4µA (MAX.) at TA =25
o
C
n COMPATIBLEWITH TTL OUTPUTS:
VIH =2V(MIN),VIL = 0.8V(MAX)
n POWER DOWN PROTECTION ON INPUTS &
OUTPUTS
n SYMMETRICAL OUTPUT IMPEDANCE:
|IOH|=IOL = 8 mA (MIN)
n BALANCED PROPAGATIONDELAYS:
tPLH ≅ tPHL
n OPERATINGVOLTAGERANGE:
VCC (OPR) = 4.5Vto 5.5V
n PIN AND FUNCTION COMPATIBLE WITH
74 SERIES257
n IMPROVEDLATCH-UP IMMUNITY
n LOWNOISE: V
OLP
=0.8V (Max.)
DESCRIPTION
The 74VHCT257A is an advanced high-speed
CMOS QUAD 2 CHANNEL MULTIPLEXER
(3-STATE) fabricated with sub-micron silicon gate
and double-layer metal wiring C
2
MOS
technology.
It is composed of four independent 2 channel
multiplexers with common SELECT and ENABLE
INPUT.
The 74VHCT257A is a non inverting multiplexer.
When the ENABLE INPUT is held ”High”, all
outputs become high impedance state. If
SELECT INPUT is held ”Low”, ”A” data is
selected, when SELECT INPUT is ”High”, ”B”
data is chosen.
Power down protection is provided on all inputs
and output and 0 to 7V can be accepted on
inputs with no regard to the supply voltage. This
device can be used to interface 5V to 3V.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS

SOP TSSOP
ORDER CODES
PACKAGE TUBE T & R
SOP 74VHCT257AM 74VHCT257AMTR
TSSOP 74VHCT257ATTR
1/9