MC54HC138A Motorola, MC54HC138A Datasheet - Page 4

• Manufacturer Part Number: MC54HC138A
• Description: 1-OF-8 DECODER / DEMULTIPLEXER
• Manufacturer: Motorola

MOTOROLA
ADDRESS INPUTS
A0, A1, A2 (Pins 1, 2, 3)
determine which of the eight outputs is active–low.
CONTROL INPUTS
CS1, CS2, CS3 (Pins 6, 4, 5)
at a low level, the chip is selected and the outputs follow the
MC54/74HC138A
Address inputs. These inputs, when the chip is selected,
Chip select inputs. For CS1 at a high level and CS2, CS3
OUTPUT Y
OUTPUT Y
CS2, CS3
INPUT A
INPUT
t PLH
90%
50%
10%
50%
50%
VALID
90%
50%
t f
10%
Figure 1.
Figure 3.
t PHL
t THL
VALID
t PHL
t r
t PLH
SWITCHING WAVEFORMS
t TLH
PIN DESCRIPTIONS
V CC
GND
V CC
GND
4
INPUT CS1
OUTPUT Y
Address inputs. For any other combination of CS1, CS2, and
CS3, the outputs are at a logic high.
OUTPUTS
Y0 – Y7 (Pins 15, 14, 13, 12, 11, 10, 9, 7)
level when addressed and the chip is selected. These out-
puts remain high when not addressed or the chip is not
selected.
Active–low Decoded outputs. These outputs assume a low
t PHL
* Includes all probe and jig capacitance
t THL
10%
DEVICE
UNDER
Figure 4. Test Circuit
50%
TEST
90%
90%
50%
t r
10%
Figure 2.
OUTPUT
High–Speed CMOS Logic Data
TEST POINT
t f
C L *
t PLH
t TLH
DL129 — Rev 6
V CC
GND