M74HC238
3 TO 8 LINE DECODER
■ HIGH SPEED:
t
= 15ns (TYP.) at VCC = 6V
PD
■ LOW POWER DISSIPATION:
I
= 4µA(MAX.) at TA=25°C
CC
■ HIGH NOISE IMMUNITY:
V
= V
NIH
■ SYMMETRICAL OUTPUT IMPEDANCE:
|I
| = IOL = 4mA (MIN)
OH
■ BALANCED PROPAGATION DELAYS:
t
≅ t
PLH
■ WIDE OPERATING VOLTAGE RANGE:
V
(OPR) = 2V to 6V
CC
■ PIN AND FUNCTION COMPATIBLE WITH
= 28 % VCC (MIN.)
NIL
PHL
74 SERIES 238
DESCRIPTION
The M74HC238 is an hi gh speed CMOS 3 TO 8
LINE DECODER fabricated with silicon gate
2
C
MOS technology.
If the device is enabled, 3 binary select inputs (A,
B and C) determine which one of outputs will go
high. When enable input G1 is held "Low" or either
G2A
or G2B is held "High" decoding func tion is
TSSOPDIP SOP
ORDER CODES
PACKAGE TUBE T & R
DIP M74HC238B1R
SOP M74HC238M1R M74HC238RM13TR
TSSOP M74HC238TTR
inhibited and all the 8 outputs go low. Three
enable inputs are provided to ease cascade
connection and application of this address
decoder in memory systems.
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS
1/10July 2001
M74HC238
INPUT AND OUTPUT EQUIVALENT CIRCUIT PIN DESCRIPTION
PIN No SYMBOL NAME AND FUNCTION
1, 2, 3 A, B, C Data Inputs
4, 5 G2A
6 G1 Data Enable Input (Active
15, 14, 13,
12, 1 1, 10, 9,
7
8 GND Ground (0V)
16 V
TRUTH TABLE
G2B Enable Input (Active
Y0 to Y7 Outputs
CC
LOW)
HIGH)
Positive Supply Voltage
INPUTS
ENABLE SELECT
G2B
G2A G1 C B A Y0Y1Y2Y3Y4Y5Y6Y7
XXLXXXLLLLLLLL NONE
XHXXXXLLLLLLLL NONE
HXXXXXLLLLLLLL NONE
LLHLLLHLLLLLLL Y0
LLHLLHLHLLLLLL Y1
LLHLHLLLHLLLLL Y2
LLHLHHLLLHLLLL Y3
LLHHLLLLLLHLLL Y4
LLHHLHLLLLLHLL Y5
LLHHHLLLLLLLHL Y6
LLHHHHLLLLLLLH Y7
X : Don’t Care
OUTPUTS
SELECTED
OUTPUT
LOGIC DIAGRAM
This log i c diagram has not be used to est i m at e propagation delays
2/10
M74HC238
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
V
V
I
I
OK
I
I
or I
CC
P
T
T
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
(*) 500mW at 65
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Value Unit
V
V
V
T
t
r
Supply Voltage
CC
DC Input Voltage -0.5 to VCC + 0.5
I
DC Output Voltage -0.5 to VCC + 0.5
O
DC Input Diode Current
IK
DC Output Diode Current
DC Output Current
O
DC VCC or Ground Current
GND
Power Dissipation
D
Storage Temperature
stg
Lead Temperature (10 sec)
L
°C; derate to 300mW by 10mW/°C from 65°C to 85°C
Supply Voltage
CC
Input Voltage 0 to V
I
Output Voltage 0 to V
O
Operating Temperature
op
Input Rise and Fall Time VCC = 2.0V
, t
f
V
V
CC
CC
= 4.5V
= 6.0V
-0.5 to +7 V
± 20 mA
± 20 mA
± 25 mA
± 50 mA
500(*) mW
-65 to +150 °C
300 °C
2 to 6 V
CC
CC
-55 to 125 °C
0 to 1000 ns
0 to 500 ns
0 to 400 ns
V
V
V
V
3/10
Loading...