DS36276
FAILSAFE Multipoint Transceiver
General Description
The DS36276 FAILSAFE Multipoint Transceiver is designed
for use on bi-directional differential busses. It is compatible
with existing TIA/EIA-485 transceivers, however, it offers an
additional feature not supported by standard transceivers.
The FAILSAFE feature guarantees the receiver output to a
known state when the Interface is in the following conditions:
Floating Line, Idle Line (no active drivers), and Line Fault
conditions (open or short). The receiver output is in a HIGH
state for the following conditions: OPEN Inputs, Terminated
Inputs (50Ω), and SHORTED Inputs.
FAILSAFE is a highly desirable feature when the transceiv-
ers are used with Asynchronous Controllers such as UARTs.
Features
nFAILSAFE receiver, RO = HIGH for:
— OPEN inputs
— Terminated inputs
— SHORTED inputs
nCompatible with popular interface standards:
— TIA/EIA-485 (RS-485)
— TIA/EIA-422-A (RS-422-A)
— CCITT Recommendation V.11
nBi-Directional Transceiver
— Designed for multipoint transmission
nSeparate driver input, driver enable, receiver enable,
and receiver output for maximum flexibility
nWide bus common mode range
— (−7V to +12V)
nPin compatible with: DS75176B, DS96176, DS3695 and
SN75176A and B
nAvailable in SOIC package
Connection and
Logic Diagram Truth Tables
Driver
Inputs Outputs
RE DE DI DO/RI DO /RI
XHH H L
XHL L H
XLX Z Z
Receiver
Inputs Output
RE DE RI–RI RO
LL ≥0V H
LL≤−500 mV L
HX X Z
Receiver FAILSAFE
Inputs Output
RE DE RI–RI RO
L L SHORTED H
L L OPEN H
HX X Z
TRI-STATE®is a registered trademark of National Semiconductor Corporation.
DS011383-1
Order Number DS36276M
See NS Package Number M08A
July 1998
DS36276 FAILSAFE Multipoint Transceiver
© 1999 National Semiconductor Corporation DS011383 www.national.com
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
)7V
Input Voltage (DE, RE , and DI) 5.5V
Driver Output Voltage/
Receiver Input Voltage −10V to +15V
Receiver Output Voltage (RO) 5.5V
Maximum Package Power Dissipation @+25˚C
M Package
(derate 5.8 mW/˚C above
+25˚C) 726 mW
Storage Temperature Range −65˚C to +150˚C
Lead Temperature (Soldering 4
sec.) 260˚C
Max Junction Temperature 150˚C
ESD Rating (HBM, 1.5 kΩ, 100
pF) ≥6.0 kV
Recommended Operating
Conditions
Min Max Units
Supply Voltage, V
CC
4.75 5.25 V
Bus Voltage −7 +12 V
Operating Temperature (T
A
)
DS36276 0 +70 ˚C
Electrical Characteristics (Notes 2, 4)
Over recommended Supply Voltage and Operating Temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Units
DRIVER CHARACTERISTICS
V
OD
Differential Output Voltage I
O
= 0 mA (No Load) 1.5 4.8 6.0 V
V
oDO
Output Voltage I
O
= 0 mA (Output to GND) 0 6.0 V
V
oDO
Output Voltage 0 6.0 V
V
T1
Differential Output Voltage
(Termination Load) R
L
=54Ω(485) (
Figure 1
) 1.5 2.0 5.0 V
R
L
= 100Ω(422) 2.0 2.3 5.0 V
∆V
T1
Balance of V
T1
|V
T1
|−|V
T1
|R
L
=54Ω(Note 3) −0.2 0.07 +0.2 V
R
L
= 100Ω−0.2 0.07 +0.2 V
V
OS
Driver Common Mode
Output Voltage R
L
=54Ω(
Figure 1
) 0 2.5 3.0 V
R
L
= 100Ω0 2.3 3.0 V
∆V
OS
Balance of V
OS
|V
OS
|−|V
OS
|R
L
=54Ω(Note 3) −0.2 0.08 +0.2 V
R
L
= 100Ω−0.2 0.08 +0.2 V
I
OSD
Driver Short-Circuit
Output Current V
O
= +12V (
Figure 3
) 134 290 mA
V
O
=V
CC
140 mA
V
O
= 0V −140 mA
V
O
= −7V −180 −290 mA
RECEIVER CHARACTERISTICS
V
TH
Differential Input High
Threshold Voltage (Note 5) V
O
=V
OH
,I
O
= −0.4 mA
−7V ≤V
CM
≤+12V −0.18 0 V
V
TL
Differential Input Low
Threshold Voltage (Note 5) V
O
=V
OL
,I
O
= 8.0 mA
−7V ≤V
CM
≤+12V −0.5 −0.23 V
V
HST
Hysteresis (Note 6) V
CM
=0V 50 mV
I
IN
Line Input Current
(V
CC
= 4.75V, 5.25V, 0V) Other Input = 0V
DE=V
IH
(Note 7) V
I
= +12V 0.7 1.0 mA
V
I
= −7V −0.5 −0.8 mA
I
OSR
Short Circuit Current V
O
= 0V RO −5.0 −30 −85 mA
I
OZ
TRI-STATE®Leakage Current V
O
= 0.4 to 2.4V −20 +20 µA
V
OH
Output High Voltage
(
Figure 12
)V
ID
= 0V, I
OH
= −0.4 mA 2.5 3.5 V
V
ID
= OPEN, I
OH
= −0.4 mA 2.5 3.5 V
V
OL
Output Low Voltage
(
Figure 12
)V
ID
= −0.5V, I
OL
= +8 mA 0.25 0.6 V
V
ID
= −0.5V, I
OL
= +16 mA 0.35 0.7 V
R
IN
Input Resistance 12 19 kΩ
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Electrical Characteristics (Notes 2, 4) (Continued)
Over recommended Supply Voltage and Operating Temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Units
DEVICE CHARACTERISTICS
V
IH
High Level Input Voltage DE,
RE,
or
DI
2.0 V
CC
V
V
IL
Low Level Input Voltage GND 0.8 V
I
IH
High Level Input Current V
IH
= 2.4V 20 µA
I
IL
Low Level Input Current V
IL
= 0.4V −100 µA
V
CL
Input Clamp Voltage I
CL
= −18 mA −0.75 −1.5 V
I
CC
Output Low Voltage
Supply Current
(No Load)
DE = 3V, RE = 0V, DI = 0V 42 60 mA
I
CCR
DE = 0V, RE = 0V, DI = 0V 28 45 mA
I
CCD
DE = 3V, RE = 3V, DI = 0V 43 60 mA
I
CCX
DE = 0V, RE = 3V, DI = 0V 31 50 mA
Switching Characteristics (Note 4)
Over recommended Supply Voltage and Operating Temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Units
DRIVER CHARACTERISTICS
t
PLHD
Diff. Prop. Delay Low to High R
L
=54Ω
C
L
=50pF
C
D
=50pF
(
Figures 4, 5
)
72160 ns
t
PHLD
Diff. Prop. Delay High to Low 7 19 60 ns
t
SKD
Diff. Skew (|t
PLHD
–t
PHLD
|) 2 10 ns
t
r
Diff. Rise Time 12 50 ns
t
f
Diff. Fall Time 12 50 ns
t
PLH
Prop. Delay Low to High R
L
=27Ω,C
L
=15pF
(
Figures 6, 7
)22 45 ns
t
PHL
Prop. Delay High to Low 22 45 ns
t
PZH
Enable Time Z to High R
L
= 110Ω
C
L
=50pF
(
Figure 8
–
Figure 11
)
32 55 ns
t
PZL
Enable Time Z to Low 32 65 ns
t
PHZ
Disable Time High to Z 22 55 ns
t
PLZ
Disable Time Low to Z 16 55 ns
RECEIVER CHARACTERISTICS
t
PLH
Prop. Delay Low to High V
ID
= −1.5V to +1.5V
C
L
=15pF
(
Figures 13, 14
)
15 40 70 ns
t
PHL
Prop. Delay High to Low 15 42 70 ns
t
SK
Skew (|t
PLH
–t
PHL
|) 2 15 ns
t
PZH
Enable Time Z to High C
L
=15pF
(
Figures 15, 16
)15 50 ns
t
PZL
Enable Time Z to Low 17 50 ns
t
PHZ
Disable Time High to Z 24 50 ns
t
PLZ
Disable Time Low to Z 19 50 ns
Note 1: “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 tables of “Electrical Characteristics” specify conditions for device operation.
Note 2: Current into device pins is defined as positive. Current out of device pins is defined as negative.All voltages are referenced to ground unless otherwise speci-
fied.
Note 3: ∆|VT1| and ∆|VOS| are changes in magnitude of VT1 and VOS, respectively, that occur when the input changes state.
Note 4: All typicals are given for V CC = 5.0V and TA= +25˚C.
Note 5: Threshold parameter limits specified as an algebraic value rather than by magnitude.
Note 6: Hysteresis defined as VHST =V
TH −V
TL.
Note 7: IIN includes the receiver input current and driver TRI-STATE leakage current.
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Parameter Measurement Information
DS011383-2
FIGURE 1. Driver V
T1
and V
OS
Test Circuit
DS011383-3
FIGURE 2. Driver V
OH
and V
OL
Test Circuit
DS011383-4
FIGURE 3. Driver Short Circuit Test Circuit
DS011383-5
FIGURE 4. Driver Differential Propagation Delay and Transition Time Test Circuit
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Parameter Measurement Information (Continued)
DS011383-6
FIGURE 5. Driver Differential Propagation Delays and Transition Times
DS011383-7
FIGURE 6. Driver Propagation Delay Test Circuit
DS011383-8
FIGURE 7. Driver Propagation Delays
DS011383-9
S1 to DO for DI = 3V
S1 to DO for DI = 0V
FIGURE 8. Driver TRl-STATE Test Circuit (t
PZH
,t
PHZ
)
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Parameter Measurement Information (Continued)
DS011383-10
FIGURE 9. Driver TRI-STATE Delays (t
PZH
,t
PHZ
)
DS011383-11
S1 to DO for DI = 0V
S1 to DO for DI = 3V
FIGURE 10. Driver TRI-STATE Test Circuit (t
PZL
,t
PLZ
)
DS011383-12
FIGURE 11. Driver TRl-STATE Delays (t
PZL
,t
PLZ
)
DS011383-13
FIGURE 12. Receiver V
OH
and V
OL
DS011383-14
FIGURE 13. Receiver Propagation Delay Test Circuit
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Parameter Measurement Information (Continued)
DS011383-15
FIGURE 14. Receiver Propagation Delays
DS011383-16
FIGURE 15. Receiver TRI-STATE Delay Test Circuit
DS011383-17
S1 1.5V
S2 OPEN
S3 CLOSED
DS011383-18
S1 −1.5V
S2 CLOSED
S3 OPEN
DS011383-19
S1 1.5V
S2 CLOSED
S3 CLOSED
DS011383-20
S1 −1.5V
S2 CLOSED
S3 CLOSED
Note 8: The input pulse is supplied by a generator having the following characteristics: f = 1.0 MHz, 50%duty cycle, trand t f<6.0 ns, ZO=50Ω.
Note 9: CLincludes probe and stray capacitance.
Note 10: Diodes are 1N916 or equivalent.
FIGURE 16. Receiver Enable and Disable Timing
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Typical Performance Characteristics
Differential Output Voltage
vs Output Current
DS011383-21
Differential Output Voltage
vs Output Current
DS011383-22
Driver V
OH
vs I
OH
vs V
CC
DS011383-23
Driver V
OH
vs I
OH
vs Temperature
DS011383-24
Driver V
OL
vs I
OL
vs V
CC
DS011383-25
Driver V
OL
vs I
OL
vs Temperature
DS011383-26
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Typical Performance Characteristics (Continued)
Receiver V
OH
vs I
OH
vs V
CC
DS011383-27
Receiver V
OH
vs I
OH
vs Temperature
DS011383-28
Receiver V
OL
vs I
OL
vs V
CC
DS011383-29
Receiver V
OL
vs I
OL
vs Temperature
DS011383-30
Supply Currrent vs Supply Voltage
DS011383-31
Supply Current vs Temperature
DS011383-32
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Typical Performance Characteristics (Continued)
Voltage Output vs Voltage Input
(Hysteresis)
DS011383-33
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11
Physical Dimensions inches (millimeters) unless otherwise noted
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DE-
VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI-
CONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or sys-
tems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, and whose fail-
ure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be rea-
sonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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Tel: 1-800-272-9959
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Tel: 81-3-5639-7560
Fax: 81-3-5639-7507
Order Number DS36276M
NS Package Number M08A
DS36276 FAILSAFE Multipoint Transceiver
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
