74VHCT238A
3 TO 8 LINE DECODER
s HIGH SPEED: tPD = 5.5 ns (TYP.) at VCC = 5V
s LOW POWER DISSIPATION:
ICC = 4 µA (MAX.) at TA=25°C
s COMPATIBLE WITH TTL OUTPUTS:
VIH = 2V (MIN.), VIL = 0.8V (MAX)
s POWER DOWN PROTECTION ON INPUTS
& OUTPUTS
s SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 8 mA (MIN)
s BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
s OPERATING VOLTAGE RANGE:
VCC(OPR) = 4.5V to 5.5V
s PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 238
s IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The 74VHCT238A is an advanced high-speed
CMOS 3 TO 8 LINE DECODER fabricated with
sub-micron silicon gate and double-layer metal
wiring C2MOS technology.
When the device is enabled, 3 binary select inputs
(A, B, and C) determine which one of the outputs
will go high. If enable input G1 is held low or either
G2A or G2B is held high, decoding function is
inhibited and all the 8 outputs go to low.
SOP
TSSOP
Table 1: Order Codes
PACKAGE
SOP
TSSOP
T&R
74VHCT238AMTR
74VHCT238ATTR
The three enable inputs are provided to ease
cascade connection and application of address
decoders for memory systems.
Power down protection is provided on all inputs
and outputs 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 since all
inputs are equipped with TTL threshold.
All inputs and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
Figure 1: Pin Connection And IEC Logic Symbols
December 2004
Rev. 3
1/12