SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D
Meets EIA Standard RS-485
D
Designed for High-Speed Multipoint
Transmission on Long Bus Lines in Noisy
Environments
D
Supports Data Rates up to and Exceeding
Ten Million Transfers Per Second
D
Common-Mode Output Voltage Range of
7 V to 12 V
D
Positive- and Negative-Current Limiting
D
Low Power Consumption . . . 1.5 mA Max
(Output Disabled)
description
The SN55LBC174 is composed of monolithic
quadruple differential line drivers with 3-state
outputs. This device is designed to meet the
requirements of the Electronics Industry
Association (EIA) Standard RS-485 and is
optimized for balanced multipoint bus
transmission at data rates up to and exceeding 10
million bits per second. Each driver features wide
positive and negative common-mode output
voltage ranges, current limiting, and
thermal-shutdown protection making it suitable
for party-line applications in noisy environments.
This device is designed using LinBiCMOS
TM
,
facilitating ultra-low power consumption and
inherent robustness.
The SN55LBC174 provides positive and negative-current limiting and thermal shutdown for protection from line
fault conditions on the transmission bus line. This device offers optimum performance when used with the
SN55LBC173 quadruple line receiver. The SN55LBC174 is available in the 16-pin CDIP package (J), the 16-pin
CPAK (W), or the 20-pin LCCC package (FK).
The SN55LBC174 is characterized for operation over the military temperature range of 55
C to 125
C.
FUNCTION TABLE
(each driver)
INPUT
ENABLE
OUTPUTS
INPUT
ENABLE
Y
Z
H
H
H
L
L
H
L
H
X
L
Z
Z
H = high level, L = low level, X = irrelevant,
Z = high impedance (off)
Copyright
1995, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
1A
1Y
1Z
1, 2EN
2Z
2Y
2A
GND
V
CC
4A
4Y
4Z
3, 4EN
3Z
3Y
3A
J OR W PACKAGE
(TOP VIEW)
NC No internal connection
FK PACKAGE
(TOP VIEW)
19
20
1
3
2
17
18
16
15
14
13
12
11
9
10
5
4
6
7
8
4Y
4Z
NC
3, 4EN
3Z
3Z
1, 2EN
NC
2Z
2Y
1Y
1A
NC
4A
GND
NC
3A
3Y
2A
V
CC
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
LinBiCMOS is a trademark of Texas Instruments Incorporated.
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
logic symbol
EN
EN
4A
3A
3, 4EN
2A
1A
1, 2EN
15
9
12
7
1
4
4Z
4Y
3Z
3Y
2Z
2Y
1Z
1Y
13
14
11
10
5
6
3
2
This symbol is in accordance with ANSI/IEEE Std 91-1984
and IEC Publication 617-12.
Pin numbers shown are for the J or W package.
logic diagram (positive logic)
1A
1Y
1Z
2A
2Y
2Z
1, 2EN
3A
3Y
3Z
4A
4Y
4Z
3, 4EN
1
4
7
9
12
15
13
14
11
10
5
6
3
2
schematic of inputs and outputs
Input
50
A
VCC
Driver
Output
VCC
200
ALL INPUTS
Y OR Z OUTPUT
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
absolute maximum ratings over operating free-air temperature (unless otherwise noted)
Supply voltage range, V
CC
(see Note 1)
0.3 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output voltage range, V
O
10 V to 15 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, V
I
0.3 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous power dissipation
internally limited
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
55
C to 125
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Storage temperature range, T
stg
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds
65
C to 150
C
. . . . . . . . . . . . . . . . . . . . . . .
Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
The maximum operating junction temperature is internally limited. Use the dissipation rating table to operate below this temperature.
NOTE 1: All voltage values are with respect to GND.
DISSIPATION RATING TABLE
PACKAGE
TA
25
C
POWER RATING
DERATING FACTOR
ABOVE TA = 25
C
TA = 125
C
POWER RATING
FK
1375 mW
11.0 mW/
C
275 mW
J
1375 mW
11.0 mW/
C
275 mW
W
1000 mW
8.0 mW/
C
200 mW
recommended operating conditions
MIN
NOM
MAX
UNIT
Supply voltage, VCC
4.75
5
5.25
V
High-level input voltage, VIH
2
V
Low-level input voltage, VIL
0.8
V
Voltage at any bus terminal (separately or common mode) VO
Y or Z
12
V
Voltage at any bus terminal (separately or common mode), VO
Y or Z
7
V
High-level output current, IOH
Y or Z
60
mA
Low-level output current, IOL
Y or Z
60
mA
Operating free-air temperature, TA
55
125
C
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
VIK
Input clamp voltage
II = 18 mA
1.5
V
|VOD|
Differential output voltage
RL = 54
,
See Figure 1
1.1
1.8
5
V
|VOD|
Differential output voltage
RL = 60
,
See Figure 2
1.1
1.7
5
V
|VOD|
Change in magnitude of differential output voltage
0.2
V
VOC
Common mode output voltage
RL = 54
See Figure 1
3
V
VOC
Common-mode output voltage
RL = 54
,
See Figure 1
1
V
|VOC|
Change in magnitude of common-mode output voltage
0.2
V
IO
Output current with power off
VCC = 0,
VO = 7 V to 12 V
100
A
IOZ
High-impedance-state output current
VO = 7 V to 12 V
100
A
IIH
High-level input current
VI = 2.4 V
100
A
IIL
Low-level input current
VI = 0.4 V
100
A
IOS
Short-circuit output current
VO = 7 V to 12 V
250
mA
ICC
Supply current (all drivers)
No load
Outputs enabled
7
mA
ICC
Supply current (all drivers)
No load
Outputs disabled
1.5
mA
All typical values are at VCC = 5 V and TA = 25
C.
The minimum VOD specification does not fully comply with EIA Standard RS-485 at operating temperatures below 0
C. The lower output signal
should be used to determine the maximum signal transmission distance.
|VOD| and
|VOC| are the changes in magnitude of VOD and VOC, respectively, that occur when the input is changed from a high level to a low
level.
switching characteristics, V
CC
= 5 V
PARAMETER
TEST CONDITIONS
TA
MIN
TYP
MAX
UNIT
td(OD)
Differential output delay time
RL = 54
See Figure 3
25
C
2
11
20
ns
td(OD)
Differential output delay time
RL = 54
,
See Figure 3
55
C to 125
C
2
40
ns
tt(OD)
Differential output transition time
RL = 54
See Figure 3
25
C
4
15
25
ns
tt(OD)
Differential output transition time
RL = 54
,
See Figure 3
55
C to 125
C
4
40
ns
tPZH
Output enable time to high level
RL = 110
See Figure 4
25
C
30
ns
tPZH
Output enable time to high level
RL = 110
,
See Figure 4
55
C to 125
C
40
ns
tPZL
Output enable time to low level
RL = 110
See Figure 5
25
C
30
ns
tPZL
Output enable time to low level
RL = 110
,
See Figure 5
55
C to 125
C
40
ns
tPHZ
Output disable time from high level
RL = 110
See Figure 4
25
C
50
ns
tPHZ
Output disable time from high level
RL = 110
,
See Figure 4
55
C to 125
C
90
ns
tPLZ
Output disable time from low level
RL = 110
See Figure 5
25
C
30
ns
tPLZ
Out ut disable time from low level
RL = 110
,
See Figure 5
55
C to 125
C
45
ns
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
VOC
2
RL
2
RL
VOD2
Figure 1. Differential and Common-Mode Output Voltages
R2 = 375
VOD
RL = 60
Vtest
Vtest
0 V or 3 V
A
R1 = 375
Y
Z
7 V < Vtest < 12 V
EN at 5 V
Figure 2. Driver V
OD
Test Circuit
VOLTAGE WAVEFORMS
50%
tt(OD)
td(OD)
10%
tt(OD)
2.5 V
2.5 V
90%
50%
Output
td(OD)
0 V
3 V
Input
Output
1.5 V
1.5 V
TEST CIRCUIT
CL = 50 pF
(see Note B)
RL = 54
50
Generator
(see Note A)
3 V
Input
NOTES: A. The input pulse is supplied by a generator having the following characteristics: PRR
1 MHz, duty cycle
50%, tr
5 ns,
tf
5 ns, ZO = 50
.
B. CL includes probe and stray capacitance.
Figure 3. Driver Differential-Output Test Circuit Delay and Transition-Time Waveforms
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
6
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
RL = 110
VOLTAGE WAVEFORMS
TEST CIRCUIT
Output
Input
tPZH
1.5 V
2.3 V
0.5 V
tPHZ
1.5 V
VOH
Voff
0 V
0 V
3 V
Output
3 V or 0 V
S1
CL = 50 pF
(see Note B)
Generator
(see Note A)
50
Input
NOTES: A. The input pulse is supplied by a generator having the following characteristics: PRR
1 MHz, duty cycle
50%, tr
5 ns,
tf
5 ns, ZO = 50
.
B. CL includes probe and stray capacitance.
Figure 4. t
PZH
and t
PHZ
Test Circuit and Waveforms
VOLTAGE WAVEFORMS
TEST CIRCUIT
Output
RL = 110
5 V
5 V
VOL
0.5 V
tPZL
3 V
tPLZ
1.5 V
2.3 V
1.5 V
Output
Input
0 V
0 V or 3 V
S1
CL = 50 pF
(see Note B)
Generator
(see Note A)
50
Input
NOTES: A. The input pulse is supplied by a generator having the following characteristics: PRR
1 MHz, duty cycle
50%, tr
5 ns,
tf
5 ns, ZO = 50
.
B. CL includes probe and stray capacitance.
Figure 5. t
PZL
and t
PLZ
Test Circuit and Waveforms
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
7
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 6
IO Output Current
A
VO Output Voltage V
OUTPUT CURRENT
vs
OUTPUT VOLTAGE
Output Disabled
TA = 25
C
40
30
20
10
0
10
20
30
40
20
15
10
5
0
5
10
15
20
50
25
50
25
I O
VCC = 5 V
VCC = 0
Figure 7
IOL Low-Level Output Current mA
LOW-LEVEL OUTPUT VOLTAGE
vs
LOW-LEVEL OUTPUT CURRENT
Low-Level Output V
oltage V
OL
V
3.5
3
2.5
2
1.5
1
0.5
80
60
40
20
0
4
0
100
VCC = 5 V
TA = 25
C
4.5
5
120
20
Figure 8
3
2.5
2
1.5
1
0.5
40
20
0
20
40
0
60
TA Free-Air Temperature
C
Differential Output V
oltage V
60
DIFFERENTIAL OUTPUT VOLTAGE
vs
FREE-AIR TEMPERATURE
V
OD
80
100
RL = 54
VCC = 5 V
Figure 9
IOH High-Level Output Current mA
High-Level Output V
oltage V
4.5
4
3.5
3
2.5
2
1.5
5
HIGH-LEVEL OUTPUT VOLTAGE
vs
HIGH-LEVEL OUTPUT CURRENT
40
20
60
0
V
OH
80
100
VCC = 5 V
TA = 25
C
120
20
SN55LBC174
QUADRUPLE LOW-POWER DIFFERENTIAL LINE DRIVER
SGLS082 MARCH 1995
8
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
TYPICAL CHARACTERISTICS
Figure 10
IO Output Current mA
DIFFERENTIAL OUTPUT VOLTAGE
vs
OUTPUT CURRENT
3
2.5
2
1.5
1
0.5
90
80
70
60
50
40
30
20
10
0
Differential Output V
oltage V
0
OD
V
100
VCC = 5 V
TA = 25
C
Figure 11
TA Free-Air Temperature
C
PROPAGATION DELAY TIME,
DIFFERENTIAL OUTPUT
vs
FREE-AIR TEMPERATURE
11
10
9
8
7
6
5
100
80
60
40
20
0
20
40
4
12
Propagation
Delay
T
ime, Differential Output ns
60
13
14
RL = 54
CL = 50 pF
VCC = 5 V
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accordance with TI's standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
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Copyright
1998, Texas Instruments Incorporated
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