DS36C278
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SNLS096C – JULY 1998 – REVISED APRIL 2013
DS36C278 Low Power Multipoint EIA-RS-485 Transceiver
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FEATURES
DESCRIPTION
•
The DS36C278 is a low power differential bus/line
transceiver designed to meet the requirements of RS485 standard for multipoint data transmission. In
addition it is compatible with TIA/EIA-422-B.
1
2
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•
•
•
•
•
•
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(1)
100% RS-485 Compliant
– Guaranteed RS-485 Device Interoperation
Low Power CMOS Design: ICC 500 μA Max
Built-In Power Up/Down Glitch-Free Circuitry
– Permits Live Transceiver
Insertion/Displacement
PDIP and SOIC Packages Available
Industrial Temperature Range: −40°C to
+85°C
On-Board Thermal Shutdown Circuitry
– Prevents Damage to the Device in the Event
of Excessive Power Dissipation
Wide Common Mode Range: −7V to +12V
Receiver Open Input Fail-Safe (1)
¼ Unit Load (DS36C278): ≥12 Nodes
½ Unit Load (DS36C278T): ≥64 Nodes
ESD (Human Body Model): ≥2 kV
Drop in Replacement for:
– LTC485, MAX485, DS75176, DS3695
The CMOS design offers significant power savings
over its bipolar and ALS counterparts without
sacrificing ruggedness against ESD damage. The
device is ideal for use in battery powered or power
conscious applications. ICC is specified at 500 μA
maximum.
The driver and receiver outputs feature TRI-STATE
capability. The driver outputs operate over the entire
common mode range of −7V to +12V. Bus contention
or fault situations that cause excessive power
dissipation within the device are handled by a thermal
shutdown circuit, which forces the driver outputs into
the high impedance state.
The receiver incorporates a fail safe circuit which
guarantees a high output state when the inputs are
left open. (1)
The DS36C278T is fully specified over the industrial
temperature range (−40°C to +85°C).
Non-terminated, open input only
Connection Diagram
Figure 1. 8-Pin PDIP or SOIC
Package Numbers D0008A and P0008E
1
2
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.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 1998–2013, Texas Instruments Incorporated
DS36C278
SNLS096C – JULY 1998 – REVISED APRIL 2013
www.ti.com
Pin Descriptions
Pin No.
Name
Description
1
RO
Receiver Output: When RE (Receiver Enable) is LOW, the receiver is enabled (ON), if DO/RI ≥ DO*/RI* by 200 mV, RO
will be HIGH. If DO/RI ≤ DO*/RI* by 200 mV, RO will be LOW. Additionally RO will be HIGH for OPEN (Non-terminated)
Inputs.
2
RE*
Receiver Output Enable: When RE* is LOW the receiver output is enabled. When RE* is HIGH, the receiver output is in
TRI-STATE (OFF).
3
DE
Driver Output Enable: When DE is HIGH, the driver outputs are enabled. When DE is LOW, the driver outputs are in
TRI-STATE (OFF).
4
DI
Driver Input: When DE (Driver Enable) is HIGH, the driver is enabled, if DI is LOW, then DO/RI will be LOW and
DO*/RI* will be HIGH. If DI is HIGH, then DO/RI is HIGH and DO*/RI* is LOW.
5
GND
Ground Connection.
6
DO/RI
Driver Output/Receiver Input, 485 Bus Pin.
7
DO*/RI* Driver Output/Receiver Input, 485 Bus Pin.
8
VCC
Positive Power Supply Connection: Recommended operating range for VCC is +4.75V to +5.25V.
Table 1. Truth Table (1)
DRIVER SECTION
RE*
DE
DI
DO/RI
X
H
H
H
DO*/RI*
L
X
H
L
L
H
X
L
X
Z
Z
RECEIVER SECTION
(1)
RE*
DE
RI-RI*
RO
L
L
≥+0.2V
H
L
L
≤−0.2V
L
H
L
X
Z
L
L
OPEN
(1)
H
Non-terminated, open input only
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings (1) (2)
Supply Voltage (VCC)
+12V
−0.5V to (VCC +0.5V)
Input Voltage (DE, RE*, & DI)
Common Mode (VCM)
Driver Output/Receiver Input
±15V
Input Voltage (DO/RI, DO*/RI*)
±14V
−0.5V to (VCC +0.5V)
Receiver Output Voltage
Maximum Package Power Dissipation
@ +25°C
D0008A Package 1190 mW, derate
9.5 mW/°C above +25°C
P0008E Package 744 mW, derate
6.0 mW/°C above +25°C
−65°C to +150°C
Storage Temperature Range
Lead Temperature
(Soldering 4 sec)
(1)
(2)
2
+260°C
“Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to
imply that the devices should be operated at these limits. The table of “Electrical Characteristics” specifies conditions of device
operation.
If Military/Aerospace specified devices are required, please contact the TI Sales Office/Distributors for availability and specifications.
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SNLS096C – JULY 1998 – REVISED APRIL 2013
Recommended Operating Conditions
Supply Voltage (VCC)
Min
Typ
Max
Units
+4.75
+5.0
+5.25
V
+12
V
−7
Bus Voltage
Operating Free-Air Temperature (TA)
DS36C278T
DS36C278
Electrical Characteristics
−40
25
+85
°C
0
25
+70
°C
(1) (2)
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified
Parameter
Test Conditions
Reference
Min
Typ
Max
Units
1.5
5.0
V
0
5.0
V
0
5.0
V
DIFFERENTIAL DRIVER CHARACTERISTICS
VOD1
Differential Output Voltage
IO = 0 mA (No Load)
(422)
(485)
VOD0
Output Voltage
IO = 0 mA
VOD0*
Output Voltage
(Output to GND)
VOD2
Differential Output Voltage
RL = 50Ω
(422)
(Termination Load)
RL = 27Ω
(485)
ΔVOD2
Balance of VOD2
(3)
RL = 27Ω or 50Ω
|VOD2 − V0D2*|
Differential Output Voltage
(Full Load)
R1 = 54Ω, R2 = 375Ω
VTEST = −7V to +12V
VOC
Driver Common Mode
Output Voltage
RL = 27Ω
(485)
RL = 50Ω
(422)
IOSD
2.0
2.8
1.5
2.3
5.0
V
V
−0.2
0.1
+0.2
V
1.5
2.0
5.0
V
0
3.0
V
0
3.0
V
−0.2
+0.2
V
(422, 485)
VOD3
ΔVOC
Figure 2
Figure 3
Figure 2
(3)
Balance of VOC
|VOC − VOC*|
RL = 27Ω or
RL = 50Ω
(422, 485)
Driver Output Short-Circuit
Current
VO = +12V
(485)
200
+250
mA
VO = −7V
(485)
−190
−250
mA
(4)
+0.035
+0.2
V
RECEIVER CHARACTERISTICS
VTH
VTL
Differential Input High
Threshold Voltage
VO = VOH, IO = −0.4V
−7V ≤ VCM ≤ +12V
Differential Input Low
Threshold Voltage
VO = VOL, IO = 0.4 mA
−7V ≤ VCM ≤ +12V
Hysteresis
VCM = 0V
RIN
Input Resistance
−7V ≤ VCM ≤ +12V
RIN
Input Resistance
−7V ≤ VCM ≤ +12V
IIN
Line Input Current
Other Input = 0V,
DS36C278
DE = VIL, RE* = VIL,
VCC= 4.75 to 5.25
DS36C278T
or 0V
IING
Line Input Current Glitch
(6)
Other Input = 0V,
DS36C278
DE = VIL, RE* = VIL,
VCC = +3.0V or 0V,
DS36C278T
TA = 25°C
IB
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Input Balance Test
−0.2
(5)
VHST
(6)
(422, 485)
RS = 500Ω
DS36C278T
24
−0.035
V
70
mV
68
kΩ
DS36C278
48
68
VIN = +12V
0
0.19
0.25
mA
VIN = −7V
0
−0.1
−0.2
mA
VIN = +12V
0
0.19
0.5
mA
VIN = −7V
0
−0.1
−0.4
mA
VIN = +12V
0
0.19
0.25
mA
VIN = −7V
0
−0.1
−0.2
mA
VIN = +12V
0
0.19
0.5
mA
VIN = −7V
0
−0.1
−0.4
mA
±400
mV
(422)
(7)
kΩ
Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground
except VOD1 and VOD2.
All typicals are given for: VCC = +5.0V, TA = + 25°C.
Delta |VOD2| and Delta |VOC| are changes in magnitude of VOD2 and VOC, respectively, that occur when input changes state.
Threshold parameter limits specified as an algebraic value rather than by magnitude.
Hysteresis defined as VHST = VTH − VTL.
IIN includes the receiver input current and driver TRI-STATE leakage current.
For complete details of test, see RS-485.
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Electrical Characteristics (1) (2) (continued)
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified
Parameter
Test Conditions
VOH
High Level Output Voltage
IOH = −4 mA, VID = +0.2V
VOL
Low Level Output Voltage
IOL = +4 mA, VID = −0.2V
IOSR
Short Circuit Current
VO = GND
IOZR
TRI-STATE Leakage Current
VO = 0.4V to 2.4V
Reference
Min
Typ
RO
Figure 12
3.5
4.6
7
RO
Max
Units
V
0.3
0.5
V
35
85
mA
±1
μA
DEVICE CHARACTERISTICS
VIH
High Level Input Voltage
2.0
VCC
V
VIL
Low Level Input Voltage
GND
0.8
V
IIH
High Level Input Current
VIH = VCC
IIL
Low Level Input Current
VCC = 5V
DE,
RE*,
DI
VIL = 0V
VCC = +3.0V
2
μA
−2
μA
−2
μA
ICC
Power Supply Current
Driver and Receiver ON
200
500
μA
ICCR
(No Load)
Driver OFF, Receiver ON
200
500
μA
200
500
μA
200
500
μA
ICCD
Driver ON, Receiver OFF
ICCZ
Driver and Receiver OFF
VCC
Switching Characteristics (1) (2)
Over Supply Voltage and Operating Temperature ranges, unless otherwise specified
Parameter
Test Conditions
Reference
Min
Typ
Max
Units
10
39
80
ns
10
40
80
ns
0
1
10
ns
3
25
50
ns
DRIVER CHARACTERISTICS
tPHLD
Differential Propagation
Delay High to Low
RL = 54Ω, CL = 100 pF
tPLHD
Differential Propagation
Delay Low to High
tSKD
Differential Skew
|tPHLD − tPLHD|
tr
Rise Time
tf
Fall Time
tPHZ
Disable Time High to Z
CL = 15 pF
tPLZ
Disable Time Low to Z
RE * = L
tPZH
Enable Time Z to High
CL = 100 pF
tPZL
Enable Time Z to Low
RE * = L
Figure 7
3
25
50
ns
Figure 8, Figure 9
—
80
200
ns
Figure 10, Figure 11
—
80
200
ns
Figure 8, Figure 9
—
50
200
ns
Figure 10, Figure 11
—
65
200
ns
30
210
400
ns
30
190
400
ns
0
20
50
ns
—
50
150
ns
—
55
150
ns
—
40
150
ns
—
45
150
ns
RECEIVER CHARACTERISTICS
tPHL
Propagation Delay
High to Low
tPLH
Propagation Delay
Low to High
tSK
Skew, |tPHL − tPLH|
tPLZ
Output Disable Time
CL = 15 pF
Figure 13, Figure 14
CL = 15 pF
tPHZ
tPZL
Figure 15, Figure 16,
Figure 17
Output Enable Time
tPZH
(1)
(2)
4
All typicals are given for: VCC = +5.0V, TA = + 25°C.
CL includes probe and jig capacitance.
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SNLS096C – JULY 1998 – REVISED APRIL 2013
PARAMETER MEASUREMENT INFORMATION
Figure 2. Driver VOD2 and VOC
Figure 3. Driver VOD3
Figure 4. Driver VOH and VOL
Vtest = −7V to +12V
Figure 5. Driver IOSD
Figure 6. Driver Differential Propagation Delay Test Circuit
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Figure 7. Driver Differential Propagation Delays and Differential Rise and Fall Times
Figure 8. TRI-STATE Test Circuit (tPZH , tPHZ)
Figure 9. TRI-STATE Waveforms (tPZH, tPHZ)
Figure 10. TRI-STATE Test Circuit (tPZL, tPLZ)
6
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SNLS096C – JULY 1998 – REVISED APRIL 2013
Figure 11. TRI-STATE Waveforms (tPZL, tPLZ)
Figure 12. Receiver VOH and VOL
Figure 13. Receiver Differential Propagation Delay Test Circuit
Figure 14. Receiver Differential Propagation Delay Waveforms
Figure 15. Receiver TRI-STATE Test Circuit
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DS36C278
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Figure 16. Receiver Enable and Disable Waveforms (tPLZ, tPZL)
Figure 17. Receiver Enable and Disable Waveforms (tPHZ, tPZH)
Typical Application Information
Figure 18. Typical RS-485 Bus Interface
Unit Load
A unit load for an RS-485 receiver is defined by the input current versus the input voltage curve. The gray
shaded region is the defined operating range from −7V to +12V. The top border extending from −3V at 0 mA to
+12V at +1 mA is defined as one unit load. Likewise, the bottom border extending from +5V at 0 mA to −7V at
−0.8 mA is also defined as one unit load (see Figure 19). An RS-485 driver is capable of driving up to 32 unit
loads. This allows up to 32 nodes on a single bus. Although sufficient for many applications, it is sometimes
desirable to have even more nodes. For example, an aircraft that has 32 rows with 4 seats per row would benefit
from having 128 nodes on one bus. This would allow signals to be transferred to and from each individual seat to
1 main station. Usually there is one or two less seats in the last row of the aircraft near the restrooms and food
storage area. This frees the node for the main station.
The DS36C278, the DS36C279, and the DS36C280 all have ½ unit load and ¼ unit load (UL) options available.
These devices will allow up to 64 nodes or 128 nodes guaranteed over temperature depending upon which
option is selected. The ½ UL option is available in industrial temperature and the ¼ UL is available in commercial
temperature.
8
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SNLS096C – JULY 1998 – REVISED APRIL 2013
First, for a ½ UL device the top and bottom borders shown in Figure 19 are scaled. Both 0 mA reference points
at +5V and −3V stay the same. The other reference points are +12V at +0.5 mA for the top border and −7V at
−0.4 mA for the bottom border (see Figure 19). Second, for a ¼ UL device the top and bottom borders shown in
Figure 19 are scaled also. Again, both 0 mA reference points at +5V and −3V stay the same. The other
reference points are +12V at +0.25 mA for the top border and −7V at −0.2 mA for the bottom border (see
Figure 19).
The advantage of the ½ UL and ¼ UL devices is the increased number of nodes on one bus. In a single master
multi-slave type of application where the number of slaves exceeds 32, the DS36C278/279/280 may save in the
cost of extra devices like repeaters, extra media like cable, and/or extra components like resistors.
The DS36C279 and DS36C280 have an additional feature which offers more advantages. The DS36C279 has
an automatic sleep mode function for power conscious applications. The DS36C280 has a slew rate control for
EMI conscious applications. Refer to the sleep mode and slew rate control portion of the application information
section in the corresponding datasheet for more information on these features.
Figure 19. Input Current vs Input Voltage Operating Range
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DS36C278
SNLS096C – JULY 1998 – REVISED APRIL 2013
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REVISION HISTORY
Changes from Revision B (April 2013) to Revision C
•
10
Page
Changed layout of National Data Sheet to TI format ............................................................................................................ 9
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PACKAGE OPTION ADDENDUM
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25-Aug-2017
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
MSL Peak Temp
(2)
(6)
(3)
Op Temp (°C)
Device Marking
(4/5)
DS36C278M/NOPB
LIFEBUY
SOIC
D
8
95
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
0 to 70
DS36C
278M
DS36C278MX/NOPB
LIFEBUY
SOIC
D
8
2500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
0 to 70
DS36C
278M
DS36C278TM
LIFEBUY
SOIC
D
8
95
TBD
Call TI
Call TI
0 to 70
36C27
8TM
DS36C278TM/NOPB
LIFEBUY
SOIC
D
8
95
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
0 to 70
36C27
8TM
DS36C278TMX
LIFEBUY
SOIC
D
8
2500
TBD
Call TI
Call TI
0 to 70
36C27
8TM
DS36C278TMX/NOPB
NRND
SOIC
D
8
2500
Green (RoHS
& no Sb/Br)
CU SN
Level-1-260C-UNLIM
0 to 70
36C27
8TM
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of