TI SN75178BP

SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
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•
•
•
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SN75177B . . . D OR P PACKAGE
(TOP VIEW)
Meets EIA Standards RS-422-A and RS-485
and CCITT Recommendations V.11 and X.27
Designed for Multipoint Transmission on
Long Bus Lines in Noisy Environments
3-State Outputs
Bus Voltage Range . . . – 7 V to 12 V
Positive and Negative Current Limiting
Driver Output Capability . . . 60 mA Max
Driver Thermal Shutdown Protection
Receiver Input Impedance . . . 12 kΩ Min
Receiver Input Sensitivity . . . ± 200 mV
Receiver Input Hysteresis . . . 50 mV Typ
Operates From Single 5-V Supply
Low Power Requirements
VCC
T
EN
GND
1
8
2
7
3
6
4
5
A
B
Z
Y
SN75178B . . . P PACKAGE
(TOP VIEW)
VCC
T
EN
GND
1
8
2
7
3
6
4
5
A
B
Z
Y
THE SN75177B IS NOT
RECOMMENDED FOR NEW DESIGN
description
The SN75177B and SN75178B differential bus repeaters are monolithic integrated devices each designed for
one-way data communication on multipoint bus transmission lines. These devices are designed for balanced
transmission bus line applications and meet EIA Standard RS-422-A and RS-485 and CCITT
Recommendations V.11 and X.27. Each device is designed to improve the performance of the data
communication over long bus lines. The SN75177B and SN75178B are identical except for the complementary
enable inputs, which allow the devices to be used in pairs for bidirectional communication.
The SN75177B and SN75178B feature positive- and negative-current limiting 3-state outputs for the receiver
and driver. The receiver features high input impedance, input hysteresis for increased noise immunity, and input
sensitivity of ± 200 mV over a common-mode input voltage range of – 7 V to 12 V. The driver features thermal
shutdown for protection from line fault conditions. Thermal shutdown is designed to occur at a junction
temperature of approximately 150°C. The driver is designed to drive current loads up to 60 mA maximum.
The SN75177B and SN75178B are designed for optimum performance when used on transmission buses
employing the SN75172 and SN75174 differential line drivers, SN75173 and SN75175 differential line
receivers, or SN75176B bus transceiver.
Function Tables
SN75177B
DIFFERENTIAL INPUTS
ENABLE
A–B
EN
T
OUTPUTS
Y
Z
VID ≥ 0.2 V
– 0.2 V < VID < 0.2 V
H
H
H
L
H
?
?
?
VID ≤ 0.2 V
X
H
L
L
H
L
Z
Z
Z
SN75178B
DIFFERENTIAL INPUTS
ENABLE
A–B
EN
T
OUTPUTS
Y
Z
VID ≥ 0.2 V
– 0.2 V < VID < 0.2 V
L
H
H
L
L
?
?
?
VID ≤ 0.2 V
X
L
L
L
H
H
Z
Z
Z
H = high level, L = low level, ? = indeterminate, X = irrelevant, Z = impedance (off)
Copyright  1993, 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.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
2–1
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
logic symbols†
logic diagrams (positive logic)
SN75177B
SN75177B
EN
A
B
T
3
8
EN
EN
5
6
7
2
A
Y
B
Z
T
A
B
T
3
8
8
5
7
6
2 Receiver
EN
EN
5
7
6
2
A
Y
B
Z
T
3
8
5
7
6
2 Receiver
Driver
schematics of inputs and outputs
EQUIVALENT OF EACH INPUT
TYPICAL OF ALL DRIVER OUTPUTS
VCC
VCC
Req
Input
Output
Driver input: Req = 3 kΩ NOM
GND
Enable inputs: Req = 8 kΩ NOM
EQUIVALENT OF EACH RECEIVER INPUT
TYPICAL OF RECEIVER OUTPUT
VCC
85 Ω
NOM
VCC
960 Ω
NOM
16.8 kΩ 960 Ω
NOM
NOM
2–2
Z
Driver
† These symbols are in accordance with ANSI/IEEE Std 91-1984 and
IEC Publication 617-12.
Input
Y
SN75178B
SN75178B
EN
3
Output
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
Y
Z
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Voltage range at any bus terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 10 V to 15 V
Differential input voltage (see Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 25 V
Enable input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 V
Continuous total dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C
NOTES: 1. All voltage values, except differential input voltage, are with respect to network ground terminal.
2. Differential input voltage is measured at the noninverting input with respect to the corresponding inverting input.
DISSIPATION RATING TABLE
TA ≤ 25°C
POWER RATING
DERATING FACTOR
ABOVE TA = 25°C
TA = 70°C
POWER RATING
D
725 mW
5.8 mW/°C
464 mW
P
1000 mW
8.0 mW/°C
640 mW
PACKAGE
recommended operating conditions
Supply voltage, VCC
High-level input voltage, VIH
EN or EN
low-level input voltage, VIL
EN or EN
MAX
UNIT
5
5.25
V
– 7†
Differential input voltage, VID
Low level output current,
Low-level
current IOL
NOM
2
Common-mode input voltage, VIC
High level output current,
High-level
current IOH
MIN
4.75
Driver
Receiver
Driver
V
0.8
V
12
V
± 12
V
– 60
mA
– 400
µA
60
Receiver
8
mA
Operating free-air temperature, TA
0
70
°C
† The algebraic convention, where the less-positive (more-negative) limit is designated minimum, is used in this data sheet for common-mode input
voltage and threshold voltage.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
2–3
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
DRIVER SECTION
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
PARAMETER
TEST CONDITIONS
VIK
VO
Input clamp voltage
Output voltage
II = – 18 mA
IO = 0
|VOD1|
Differential output voltage
IO = 0
|VOD2|
Differential output voltage
|VOD3|
Differential output voltage
∆|VOD|
Change
g in magnitude
g
of
diferential output voltage‡
VOC
Common mode output voltage
Common-mode
∆|VOC|
Change
of
g in magnitude
g
common-mode output voltage‡
IO
IOZ
Output current
IIH
IIL
High-level input current
IOS
Short-circuit output current
ICC
High-impedance-state output current
Low-level input current
Supply current (total package)
TYP†
MIN
MAX
UNIT
– 1.5
V
0
6
V
1.5
6
V
RL = 100 Ω ,
See Figure 1
1/2 VOD1
or 2 §
RL = 54 Ω,
See Figure 1
1.5
See Note 3
V
2.5
1.5
RL = 54 Ω or 100 Ω
Ω,
See Figure 1
5
5
V
± 0.2
02
V
3
–1
VCC = 0,
VO = – 7 V to 12 V
VO = – 7 V to 12 V
VI = 2.4 V
VI = 0.4 V
VO = – 7 V
VO = VCC
VO = 12 V
V
02
± 0.2
V
± 100
µA
± 100
µA
20
µA
– 400
µA
– 250
250
mA
250
No load
Outputs enabled
57
70
Outputs disabled
26
35
mA
† All typical values are at VCC = 5 V and TA = 25°C.
‡ ∆|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.
§ The minimum VOD2 with a 100-Ω load is either 1/2 VOD1 or 2, whichever is greater.
NOTE 3: See Figure 3.5 of EIA Standard RS-485.
switching characteristics, VCC = 5 V, TA = 25°C
PARAMETER
TEST CONDITIONS
tdD
ttD
Differential-output delay time
tPZH
tPZL
Output enable time to high level
RL = 110 Ω,
Output enable time to low level
RL = 110 Ω,
tPHZ
tPLZ
Output disable time from high level
RL = 110 Ω,
Output disable time from low level
RL = 110 Ω,
2–4
Differential-output transition time
RL = 54 Ω
Ω,
POST OFFICE BOX 655303
TYP
MAX
15
20
ns
20
30
ns
See Figure 4
85
120
ns
See Figure 5
40
60
ns
See Figure 4
150
250
ns
See Figure 5
20
30
ns
See Figure 3
• DALLAS, TEXAS 75265
MIN
UNIT
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
SYMBOL EQUIVALENTS
DATA SHEET PARAMETER
RS-422-A
RS-485
VO
|VOD1|
Voa, Vob
Vo
Voa, Vob
Vo
|VOD2|
Vt (RL = 100 Ω)
Vt (RL = 54 Ω)
Vt (Test Termination)
Measurement 2)
∆|VOD|
| |Vt| – |Vt||
| |Vt| – |Vt||
VOC
∆|VOC|
IOS
|VOS|
|VOS – VOS|
|VOS|
|VOS – VOS|
IO
|Ixa|,|Ixb|
|VOD3|
|Isa|,|Isb|
Iia,Iib
RECEIVER SECTION
electrical characteristics over recommended ranges of common-mode input voltage, supply
voltage, and operating free-air temperature (unless otherwise noted)
PARAMETER
VT+
VT–
Positive-going input threshold voltage
Vhys
VIK
Input hysteresis (VT+ – VT–)
TEST CONDITIONS
VO = 2.7 V,
VO = 0.5 V,
Negative-going input threshold voltage
IO = – 0.4 mA
IO = 8 mA
TYP†
MAX
0.2
– 0.2‡
Input clamp voltage at EN
II = – 18 mA
VID = 200 mV,
See Figure 2
IOH = – 400 µA,
IOL = 8 mA,
High-level output voltage
VOL
Low-level output voltage
VID = – 200 mV,
See Figure 2
IOZ
High impedance state output current
High-impedance-state
VO = 0.4
0 4 V to 2
2.4
4V
II
Line input current
Other input at 0 V,
See Note 4
IIH
IIL
High-level enable-input current
ri
Input resistance
IOS
Short-circuit output current
2.7
0.45
20
– 400
VI = 12 V
VI = – 7 V
1
– 0.8
20
– 200
V
µA
mA
µA
µA
kΩ
– 15
No load
V
V
12
Supply
Su
ly current (total package)
ackage)
V
mV
– 1.5
VIH = 2.7 V
VIL = 0.4 V
Low-level enable-input current
UNIT
V
50
VOH
ICC
MIN
– 85
Outputs enabled
57
70
Outputs disabled
26
35
mA
mA
† All typical values are at VCC = 5 V, TA = 25°C.
‡ The algebraic convention, where the less-positive (more-negative) limit is designated minimum, is used in this data sheet for common-mode input
voltage and threshold voltage levels only.
NOTE 4: Refer to EIA Standard RS-422 for exact conditions.
switching characteristics, VCC = 5 V, TA = 25°C
PARAMETER
TEST CONDITIONS
tPLH
tPHL
Propagation delay time, low-to-high level output
tPZH
tPZL
Output enable time to high level
tPHZ
tPLZ
Output disable time from high level
Propagation delay time, high-to-low level output
Output enable time to high level
Output disable time from low level
POST OFFICE BOX 655303
VID = – 1.5 V to 1.5 V,,
CL = 15 pF,
See Figure 6
CL = 15 pF,
pF
See Figure 7
CL = 15 pF,
pF
See Figure 8
• DALLAS, TEXAS 75265
MIN
TYP
MAX
19
35
30
40
10
20
12
20
25
35
17
25
UNIT
ns
ns
ns
2–5
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
PARAMETER MEASUREMENT INFORMATION
RL
VOD2
2
VID
RL
2
VOH
VOC
+IOL
VOL
Figure 1. Driver VOD and VOC
– IOH
Figure 2. Receiver VOH and VOL
3V
Input
Generator
(see Note A)
RL = 54 Ω
50 Ω
1.5 V
CL = 50 pF
(see Note B)
1.5 V
0V
tdD
tdD
Output
Output
90%
50%
≈ 2.5 V
50%
10%
≈ – 2.5 V
ttD
VOLTAGE WAVEFORMS
ttD
TEST CIRCUIT
Figure 3. Driver Differential-Output Test Circuit and Voltage Waveforms
Output
S1
0 V or 3 V
Generator
(see Note A)
ÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁ
(SN75178B)
Input
3V
1.5 V
1.5 V
(SN75177B)
50 Ω
CL = 50 pF
(see Note B)
SN75178B
Enable is
Active Low
0V
0.5 V
tPZH
RL = 110 Ω
VOH
Output
2.3 V
tPHZ
Voff ≈ 0 V
VOLTAGE WAVEFORMS
TEST CIRCUIT
Figure 4. Driver Enable and Disable Times
5V
S1
RL = 110 Ω
Output
3 V or 0 V
Generator
(see Note A)
50 Ω
SN75178B
Enable is
Active Low
ÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁ
(SN75178B)
Input
3V
1.5 V
1.5 V
0V
(SN75177B)
tPZL
tPLZ
CL = 50 pF
(see Note B)
Output
2.3 V
5V
0.5 V
VOL
VOLTAGE WAVEFORMS
TEST CIRCUIT
Figure 5. Driver Enable and Disable Times
NOTES: A. The input pulse is supplied by a generator having the following characteristics: PRR ≤ 1 MHz, 50% duty cycle, tr ≤ 6 ns, tf ≤ 6 ns,
ZO = 50 Ω.
B. CL includes probe and jig capacitance.
2–6
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
PARAMETER MEASUREMENT INFORMATION
3V
Input
Generator
(see Note A)
1.5 V
Output
50 Ω
1.5 V
0V
1.5 V
CL = 15 pF
(see Note B)
tPHL
tPLH
VOH
Output
1.3 V
1.3 V
VOL
TEST CIRCUIT
VOLTAGE WAVEFORMS
Figure 6. Receiver Propagation Delay Times
S1
1.5 V
Output
S2
2 kΩ
–1.5 V
5V
CL = 15 pF
(see Note B)
Generator
(see Note A)
5 kΩ
(see Note C)
50 Ω
S3
TEST CIRCUIT
ÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁ
(SN75177B)
Input
3V
S1 to 1.5 V
S2 Open
S3 Closed
0V
1.5 V
(SN75178B)
tPZH
ÁÁÁÁÁ
ÁÁÁÁÁ
ÁÁÁÁÁ
ÁÁÁÁÁ
(SN75177B)
Input
(SN75178B)
3V
S1 to –1.5 V
S2 Closed
S3 Open
0V
1.5 V
tPZL
VOH
1.5 V
Output
ÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁ
0V
(SN75177B)
Input
(SN75178B)
1.5 V
3V
S1 to 1.5 V
S2 Closed
S3 Closed
0V
tPHZ
Output
0.5 V
≈ 4.5 V
Output
ÁÁÁÁÁ
ÁÁÁÁÁ
ÁÁÁÁÁ
1.5 V
VOL
(SN75177B)
Input
(SN75178B)
3V
S1 to –1.5 V
S2 Closed
S3 Closed
0V
1.5 V
tPLZ
≈ 1.3 V
VOH
Output
0.5 V
≈ 1.3 V
VOL
VOLTAGE WAVEFORMS
Figure 7. Receiver Output Enable and Disable Times
NOTES: A. The input pulse is supplied by a generator having the following characteristics: PRR ≤ 1 MHz, 50% duty cycle, tr ≤ 6 ns, tf ≤ 6 ns,
ZO = 50 Ω.
B. CL includes probe and jig capacitance.
C. All diodes are 1N916 or equivalent.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
2–7
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
TYPICAL CHARACTERISTICS
DRIVER HIGH-LEVEL OUTPUT VOLTAGE
vs
HIGH-LEVEL OUTPUT CURRENT
DRIVER LOW-LEVEL OUTPUT VOLTAGE
vs
LOW-LEVEL OUTPUT CURRENT
5
5
VCC = 5 V
TA = 25°C
4
3.5
3
2.5
2
ÁÁ
ÁÁ
ÁÁ
1.5
1
VCC = 5 V
TA = 25°C
4.5
VOH – High-Level Output Voltage – V
VOH – High-Level Output Voltage – V
4.5
4
3.5
3
2.5
2
ÁÁÁ
ÁÁÁ
ÁÁÁ
1.5
1
0.5
0.5
0
– 20
0
– 40
– 60
– 80
– 100
– 120
0
0
20
40
80
100
120
IOH – Low-Level Output Current – mA
IOH – High-Level Output Current – mA
Figure 8
Figure 9
DRIVER DIFFERENTIAL OUTPUT VOLTAGE
vs
DRIVER OUTPUT CURRENT
RECEIVER OUTPUT VOLTAGE
vs
DIFFERENTIAL INPUT VOLTAGE
5
4
VCC = 5 V
VCC = 5 V
TA = 25°C
3.5
IO = 0
TA = 25°C
4
VO
V
O – Output Voltage – V
VOD – Differential Output Voltage – V
60
3
2.5
2
1.5
ÁÁ
ÁÁ
VIC =
– 12 V
VIC =
0V
VIC =
12 V
3
VT–
VT+
VT–
VT–
VT+
VT+
2
1
1
0.5
0
0
10
20
30
40
50
60
70
80
90 100
0
–125 –100 –75 –50 –25
IO – Output Current – mA
Figure 10
2–8
0
25
Figure 11
POST OFFICE BOX 655303
50
75 100 125
VID – Differential Input Voltage – mV
• DALLAS, TEXAS 75265
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
TYPICAL CHARACTERISTICS
RECEIVER HIGH-LEVEL OUTPUT VOLTAGE
vs
HIGH-LEVEL OUTPUT CURRENT
RECEIVER HIGH-LEVEL OUTPUT VOLTAGE
vs
FREE-AIR TEMPERATURE
5
VID = 0.2 V
TA = 25°C
VOH – High-Level Output Voltage – V
VOH – High-Level Output Voltage – V
5
4
3
VCC = 5.25 V
2
ÁÁ
ÁÁ
ÁÁ
VCC = 5 V
VCC = 4.75 V
1
VCC = 5 V
VID = 200 mV
IOH = – 440 µA
4
3
2
ÁÁ
ÁÁ
ÁÁ
1
0
0
0
– 10
– 20
– 30
– 40
– 50
0
10
20
Figure 12
0.6
0.5
VOL – Low-Level Output Voltage – V
VOL – Low-Level Output Voltage – V
VCC = 5 V
TA = 25°C
0.4
0.3
0.2
0.1
0
15
60
70
80
RECEIVER LOW-LEVEL OUTPUT VOLTAGE
vs
FREE-AIR TEMPERATURE
0.6
10
50
Figure 13
RECEIVER LOW-LEVEL OUTPUT VOLTAGE
vs
LOW-LEVEL OUTPUT CURRENT
5
40
TA – Free-Air Temperature – °C
IOH – High-Level Output Current – mA
0
30
20
25
30
0.5
VCC = 5 V
VID = – 200 mV
IOL = 8 mA
0.4
0.3
0.2
0.1
0
– 40
– 20
0
20
40
60
80
100
120
TA – Free-Air Temperature – °C
IOL – Low-Level Output Current – mA
Figure 14
Figure 15
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
2–9
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
APPLICATION INFORMATION
1/2 SN75179B
Direction
RT
RT
Control
SN75177B
1/2 SN75179B
SN75176B
SN75176B
RT
RT
RT
RT
SN75178B
SN75176B
NOTE: The line should be terminated at both ends in its characteristic impedance. Stub lengths off the main line should be kept as short as
possible.
Figure 16. Typical Application Circuit
2–10
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
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product or service without notice, and advises its customers to obtain the latest version of relevant information
to verify, before placing orders, that the information being relied on is current and complete.
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the time of sale in 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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