SCHMITT TRIGGERS
DUAL GATE/HEX INVERTER
The SN54LS/ 74LS13 and SN54LS / 74LS14 contain logic gates / inverters
which accept standard TTL input signals and provide standard TTL output
levels. They are capable of transforming slowly changing input signals into
sharply defined, jitter-free output signals. Additionally, they have greater noise
margin than conventional inverters.
Each circuit contains a Schmitt trigger followed by a Darlington level shifter
and a phase splitter driving a TTL totem pole output. The Schmitt trigger uses
positive feedback to effectively speed-up slow input transitions, and provide
different input threshold voltages for positive and negative-going transitions.
This hysteresis between the positive-going and negative-going input
thresholds (typically 800 mV) is determined internally by resistor ratios and is
essentially insensitive to temperature and supply voltage variations.
LOGIC AND CONNECTION DIAGRAMS
VCC
14
13
SN54 / 74LS13
12
11
10
9
8
SN54/74LS13
SN54/74LS14
SCHMITT TRIGGERS
DUAL GATE/ HEX INVERTER
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 632-08
14
1
14
1
N SUFFIX
PLASTIC
CASE 646-06
1
2
3
4
5
6
7
GND
14
1
D SUFFIX
SOIC
CASE 751A-02
VCC
14
13
SN54 / 74LS14
12
11
10
9
8
ORDERING INFORMATION
SN54LSXXJ
SN74LSXXN
SN74LSXXD
Ceramic
Plastic
SOIC
1
2
3
4
5
6
7
GND
GUARANTEED OPERATING RANGES
Symbol
VCC
TA
IOH
IOL
Supply Voltage
Operating Ambient Temperature Range
Output Current — High
Output Current — Low
Parameter
54
74
54
74
54, 74
54
74
Min
4.5
4.75
– 55
0
Typ
5.0
5.0
25
25
Max
5.5
5.25
125
70
– 0.4
4.0
8.0
Unit
V
°C
mA
mA
FAST AND LS TTL DATA
5-24
SN54/74LS13
•
SN54/74LS14
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
VT+
VT–
VT+ – VT–
VIK
VOH
Parameter
Positive-Going Threshold Voltage
Negative-Going Threshold Voltage
Hysteresis
Input Clamp Diode Voltage
54
Output HIGH Voltage
74
54, 74
VOL
IT+
IT–
IIH
IIL
IOS
Output LOW Voltage
74
Input Current at Positive-Going Threshold
Input Current at Negative-Going Threshold
Input HIGH Current
0.1
Input LOW Current
Short Circuit Current (Note 1)
Power Supply Current
LS13
Total, Output HIGH
ICC
Total, Output LOW
LS14
LS13
LS14
2.9
8.6
4.1
12
6.0
16
7.0
21
mA
VCC = MAX
– 20
– 0.4
–100
0.35
– 0.14
– 0.18
1.0
20
0.5
V
mA
mA
µA
mA
mA
mA
2.7
3.4
0.25
0.4
V
V
2.5
Min
1.5
0.6
0.4
0.8
– 0.65
3.4
– 1.5
Typ
Max
2.0
1.1
Unit
V
V
V
V
V
Test Conditions
VCC = 5.0 V
VCC = 5.0 V
VCC = 5.0 V
VCC = MIN, IIN = – 18 mA
VCC = MIN, IOH = – 400
µA,
VIN = VIL
VCC = MIN, IOL = 4.0 mA, VIN = 2.0 V
VCC = MIN, IOL = 8.0 mA, VIN = 2.0 V
VCC = 5.0 V, VIN = VT+
VCC = 5.0 V, VIN = VT–
VCC = MAX, VIN = 2.7 V
VCC = MAX, VIN = 7.0 V
VCC = MAX, VIN = 0.4 V
VCC = MAX, VOUT = 0 V
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
(TA = 25°C)
Max
Symbol
tPLH
tPHL
Parameter
Propagation Delay, Input to Output
Propagation Delay, Input to Output
LS13
22
27
LS14
22
22
Unit
ns
ns
Test Conditions
VCC = 5.0 V
CL = 15 pF
3V
VIN
0V
tPHL
tPLH
1.6 V
0.8 V
VOUT
1.3 V
1.3 V
Figure 1. AC Waveforms
FAST AND LS TTL DATA
5-25
SN54/74LS13
•
SN54/74LS14
5
V O , OUTPUT VOLTAGE (VOLTS)
4
VCC = 5 V
TA = 25°C
3
2
1
0
0
0.4
0.95
1.2
VIN, INPUT VOLTAGE (VOLTS)
1.8
2
Figure 2. VIN versus VOUT Transfer Function
2
V T , THRESHOLD VOLTAGE (VOLTS)
∆
V T, HYSTERESIS (VOLTS)
TA = 25°C
VT+
1.6
1.2
VT–
0.8
∆
VT
0.4
0
4.5
4.75
5
5.25
VCC, POWER SUPPLY VOLTAGE (VOLTS)
5.5
Figure 3. Threshold Voltage and Hysteresis
versus Power Supply Voltage
1.9
V T , THRESHOLD VOLTAGE (VOLTS)
∆
V T, HYSTERESIS (VOLTS)
1.7
1.5
1.3
1.1
0.9
0.7
– 55°
VT–
∆
VT
0° 25°
75°
TA, AMBIENT TEMPERATURE (°C)
VT+
125°
Figure 4. Threshold Voltage Hysteresis
versus Temperature
FAST AND LS TTL DATA
5-26
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