SN54 / 74LS170
WRITE FUNCTION TABLE (SEE NOTES A, B, AND C)
WRITE INPUTS
WORD
WB WA EW
0
1
2
3
L L L Q = D Q0 Q0 Q0
L
H
L
Q0 Q = D Q0
Q0
H L L Q0 Q0 Q = D Q0
H H L Q0 Q0 Q0 Q = D
X X H Q0 Q0 Q0 Q0
READ FUNCTION TABLE (SEE NOTES A AND D)
READ INPUTS
OUTPUTS
RB RA ER
Q1
Q2
Q3
Q4
L L L W0B1 W0B2 W0B3 W0B4
L H L W1B1 W1B2 W1B3 W1B4
H L L W2B1 W2B2 W2B3 W2B4
H H L W3B1 W3B2 W3B3 W3B4
XXH
H
H
H
H
NOTES: A. H = HIGH Level. L = LOW Level, X = Irrelevant.
NOTES: B. (Q = D) = The four selected internal flip-flop outputs will assume the states applied to the four external data inputs.
NOTES: C. Q0 = the level of Q before the indicated input conditions were established.
NOTES: D. W0B1 = The first bit of word 0, etc.
GUARANTEED OPERATING RANGES
Symbol
Parameter
VCC
Supply Voltage
TA Operating Ambient Temperature Range
VOH
IOL
Output Voltage — High
Output Current — Low
Min Typ Max Unit
54 4.5 5.0 5.5
74 4.75 5.0 5.25
V
54 – 55 25 125 °C
74 0 25 70
54, 74
5.5 V
54 4.0 mA
74 8.0
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Limits
Symbol
Parameter
Min Typ Max Unit
Test Conditions
VIH Input HIGH Voltage
2.0
V
Guaranteed Input HIGH Voltage for
All Inputs
54
VIL Input LOW Voltage 74
0.7 Guaranteed Input LOW Voltage for
0.8 V All Inputs
VIK
IOH
VOL
Input Clamp Diode Voltage
Output HIGH Current
54, 74
Output LOW Voltage
54, 74
74
– 0.65 – 1.5 V VCC = MIN, IIN = – 18 mA
100 µA VCC = MIN, VOH = MAX
0.25 0.4
0.35 0.5
V IOL = 4.0 mA VCC = VCC MIN,
VIN = VIL or VIH
V IOL = 8.0 mA per Truth Table
Input HIGH Current
Any D, R, W
IIH ER, EW
Any D, R, W
ER, EW
Input LOW Current
IIL Any D, R, W
ER, EW
ICC Power Supply Current
20 µA VCC = MAX, VIN = 2.4 V
40
0.1
0.2
mA VCC = MAX, VIN = 7.0 V
– 0.4 mA VCC = MAX, VIN = 0.4 V
– 0.8
40 mA VCC = MAX
FAST AND LS TTL DATA
5-3