SGS Thomson Microelectronics M74HC238 Datasheet
.HIGH SPEED
tPD= 14 ns(TYP.) AT VCC=5V
.LOWPOWER DISSIPATION
ICC=4µA(MAX.) AT TA=25°C
.HIGH NOISEIMMUNITY
V
NIH=VNIL
=28%VCC(MIN.)
.OUTPUT DRIVE CAPABILITY
10 LSTTL LOADS
.SYMMETRICAL OUTPUT IMPEDANCE
|IOH|=IOL=4 mA (MIN.)
.BALANCEDPROPAGATION DELAYS
t
PLH=tPHL
.WIDE OPERATING VOLTAGE RANGE
VCC(OPR)= 2 V TO 6 V
.PIN AND FUNCTION COMPATIBLE
WITH 54/74LS238
M54HC238
M74HC238
3 TO 8 LINE DECODER
B1R
(PlasticPackage)
M1R
(MicroPackage)
ORDER CODES :
M54HC 238F1R M74H C238M1R
M74HC 238B1R M74HC2 38C1R
F1R
(CeramicPackage)
C1R
(Chip Carrier)
DESCRIPTION
TheM54/74HC238 is ahigh speed CMOS3 to8 line
decoderfabricated insilicongateC2MOStechnology.
It has the same high speed performance of LSTTL
combined with trueCMOSlowpower consumption.If
thedeviceisenabled,3 binary selectinputs(A,B and
C)determinewhichoneofoutputswillgohigh.Enable
inputG1 is held ”Low” or either G2A or G2B is held
”High” decoding function isinhibited andallthe 8 outputsgolow.Three enable inputs areprovided toease
cascade connection and application of this address
decoder inmemory systems.
Allinputs areequipped with protectioncircuitsagainst
staticdischarge and transient excess voltage.
NC =
No Internal
Connection
PIN CONNECTIONS(top view)
October 1993
1/10
M54/M74HC238
INPUT AND OUTPUT EQUIVALENT CIRCUIT
IEC LOGIC SYMBOLS
PIN DESCRIPTION
PIN No SYMBOL NAME AND FUNCTION
1, 2, 3 A, B, C Data Inputs
4, 5 G2A G2B Enable Input (Active
LOW)
6 G1 Data Enable Input
(Active HIGH)
15, 14, 13,
12, 11, 10, 9,
7
8 GND Ground (0V)
16 V
Y0 to Y7 Outputs
CC
Positive Supply Voltage
TRUTH TABLE
INPUTS
ENABLE SELECT
G2B G2A G1 C B A Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
XXLXXXLLLLLLLL NONE
XHXXXXLLLLLLLL NONE
HXXXXXLLLLLLLL NONE
LLHLLLHLLLLLLL Y0
LLHLLHLHLLLLLL Y1
LLHLHLLLHLLLLL Y2
LLHLHHLLLHLLLL Y3
LLHHLLLLLLHLLL Y4
LLHHLHLLLLLHLL Y5
LLHHHLLLLLLLHL Y6
LLHHHHLLLLLLLH Y7
X: Don’tCare
2/10
OUTPUS SELECTED
OUTPUT
LOGIC DIAGRAM
M54/M74HC238
ABSOLU TE MAXIMUM RATING S
Symbol Parameter Value Unit
V
CC
V
V
O
I
IK
I
OK
I
O
I
or I
CC
P
D
T
stg
T
AbsoluteMaximumRatingsarethose values beyond whichdamage tothedevice mayoccur. Functionaloperation under theseconditionisnotimplied.
(*)500 mW: ≅ 65oC derateto300 mW by 10mW/oC: 65oCto85oC
Supply Voltage -0.5 to +7 V
DC Input Voltage -0.5 to VCC+ 0.5 V
I
DC Output Voltage -0.5 to VCC+ 0.5 V
DC Input Diode Current ± 20 mA
DC Output Diode Current ± 20 mA
DC Output Source Sink Current Per Output Pin ± 25 mA
DC VCCor Ground Current ± 50 mA
GND
Power Dissipation 500 (*) mW
Storage Temperature -65 to +150
Lead Temperature (10 sec) 300
L
o
C
o
C
3/10
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