Texas Instruments SN75178BD, SN75178BDR, SN75178BP, SN75178BPS Datasheet
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUAR Y 1993
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Copyright 1993, Texas Instruments Incorporated
2–1
• 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
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 OUTPUTS
A – B EN T Y Z
VID ≥ 0.2 V H H H L
–0.2 V < VID < 0.2 V H ? ??
V
ID
≤ 0.2 V H L LH
X L ZZZ
SN75178B
DIFFERENTIAL INPUTS
ENABLE OUTPUTS
A – B EN T Y Z
VID ≥ 0.2 V L H H L
–0.2 V < VID < 0.2 V L ? ??
V
ID
≤ 0.2 V L L LH
X H ZZZ
H = high level, L = low level, ? = indeterminate, X = irrelevant, Z = impedance (off)
1
2
3
4
8
7
6
5
V
CC
T
EN
GND
A
B
Z
Y
SN75177B ...D OR P PACKAGE
(TOP VIEW)
1
2
3
4
8
7
6
5
V
CC
T
EN
GND
A
B
Z
Y
SN75178B ...P PACKAGE
(TOP VIEW)
THE SN75177B IS NOT
RECOMMENDED FOR NEW DESIGN
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.
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–2
logic symbols
†
logic diagrams (positive logic)
SN75178B
EN
5
6
3
8
7
2
EN
A
B
T
Y
Z
SN75177B
Z
Y
T
B
A
EN
2
7
8
3
6
5
EN
SN75178B
SN75177B
Receiver Driver
5
6
Y
Z
3
8
7
2
EN
A
B
T
T
B
A
EN
2
7
8
3
Z
Y
6
5
DriverReceiver
†
These symbols are in accordance with ANSI/IEEE Std 91-1984 and
IEC Publication 617-12.
schematics of inputs and outputs
960 Ω
NOM
GND
Output
V
CC
TYPICAL OF ALL DRIVER OUTPUTS
16.8 kΩ
NOM
Input
V
CC
EQUIVALENT OF EACH RECEIVER INPUT
Enable inputs: Req = 8 kΩ NOM
Driver input: Req = 3 kΩ NOM
Input
R
eq
V
CC
EQUIVALENT OF EACH INPUT
Output
85 Ω
NOM
V
CC
TYPICAL OF RECEIVER OUTPUT
960 Ω
NOM
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–3
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
PACKAGE
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
recommended operating conditions
MIN NOM MAX UNIT
Supply voltage, V
CC
4.75 5 5.25 V
High-level input voltage, V
IH
EN or EN 2 V
low-level input voltage, V
IL
EN or EN 0.8 V
Common-mode input voltage, V
IC
–7
†
12 V
Differential input voltage, V
ID
±12 V
p
Driver –60 mA
High-level output current, I
OH
Receiver –400 µA
p
Driver 60
Low-level output current, I
OL
Receiver 8
mA
Operating free-air temperature, T
A
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.
SN75177B, SN75178B
DIFFERENTIAL BUS REPEATERS
SLLS002C – D2606, JULY 1985 – REVISED FEBRUARY 1993
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
2–4
DRIVER SECTION
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT
V
IK
Input clamp voltage II = –18 mA –1.5 V
V
O
Output voltage IO = 0 0 6 V
|V
OD1
| Differential output voltage IO = 0 1.5 6 V
1/2 V
OD1
|V
OD2
| Differential output voltage
R
L
=
100 Ω
,
See Figure 1
OD1
or 2
§
V
RL = 54 Ω, See Figure 1 1.5 2.5 5
|V
OD3
| Differential output voltage See Note 3 1.5 5 V
Change in magnitude of
∆|V
OD|
gg
diferential output voltage
‡
±0.2
VpR
L
=
54 Ω
or
100 Ω
,See Figure
1
3
VOCCommon-mode output voltage
–1
V
Change in magnitude of
∆|VOC|
gg
common-mode output voltage
‡
±0.2
V
I
O
Output current VCC = 0, VO = –7 V to 12 V ±100 µA
I
OZ
High-impedance-state output current VO = –7 V to 12 V ±100 µA
I
IH
High-level input current VI = 2.4 V 20 µA
I
IL
Low-level input current VI = 0.4 V –400 µA
VO = –7 V –250
I
OS
Short-circuit output current
VO = V
CC
250
mA
VO = 12 V 250
pp
p
Outputs enabled 57 70
ICCSupply current (total package)
No load
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 V
OD2
with a 100-Ω load is either 1/2 V
OD1
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 MIN TYP MAX UNIT
t
dD
Differential-output delay time
15 20 ns
t
tD
Differential-output transition time
R
L
= 54 Ω,
See
Fig
u
re
3
20 30 ns
t
PZH
Output enable time to high level RL = 110 Ω, See Figure 4 85 120 ns
t
PZL
Output enable time to low level RL = 110 Ω, See Figure 5 40 60 ns
t
PHZ
Output disable time from high level RL = 110 Ω, See Figure 4 150 250 ns
t
PLZ
Output disable time from low level RL = 110 Ω, See Figure 5 20 30 ns
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