NAIS DS75176B

DS75176B/DS75176BT
Multipoint RS-485/RS-422 Transceivers
General Description
Features
The DS75176B is a high speed differential TRI-STATE ®
bus/line transceiver designed to meet the requirements of
EIA standard RS485 with extended common mode range
(+12V to −7V), for multipoint data transmission. In addition, it
is compatible with RS-422.
The driver and receiver outputs feature TRI-STATE capability, for the driver outputs over the entire common mode
range of +12V to −7V. 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.
DC specifications are guaranteed over the 0 to 70˚C temperature and 4.75V to 5.25V supply voltage range.
n Meets EIA standard RS485 for multipoint bus
transmission and is compatible with RS-422.
n Small Outline (SO) Package option available for
minimum board space.
n 22 ns driver propagation delays.
n Single +5V supply.
n −7V to +12V bus common mode range permits ± 7V
ground difference between devices on the bus.
n Thermal shutdown protection.
n High impedance to bus with driver in TRI-STATE or with
power off, over the entire common mode range allows
the unused devices on the bus to be powered down.
n Pin out compatible with DS3695/A and SN75176A/B.
n Combined impedance of a driver output and receiver
input is less than one RS485 unit load, allowing up to 32
transceivers on the bus.
n 70 mV typical receiver hysteresis.
Connection and Logic Diagram
DS008759-1
Top View
Order Number DS75176BN, DS75176BTN, DS75176BM or DS75176BTM
See NS Package Number N08E or M08A
TRI-STATE ® is a registered trademark of National Semiconductor Corp.
© 1999 National Semiconductor Corporation
DS008759
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DS75176B/DS75176BT Multipoint RS-485/RS-422 Transceivers
July 1998
Absolute Maximum Ratings (Note 1)
Recommended Operating
Conditions
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage, VCC
Control Input Voltages
Driver Input Voltage
Driver Output Voltages
Receiver Input Voltages (DS75176B)
Receiver Output Voltage
Continuous Power Dissipation @ 25˚C
for M Package
for N Package
Storage Temperature Range
Lead Temperature
(Soldering, 4 seconds)
Supply Voltage, VCC
Voltage at Any Bus Terminal
(Separate or Common Mode)
Operating Free Air Temperature TA
DS75176B
DS75176BT
Differential Input Voltage,
VID (Note 6)
7V
7V
7V
+15V/ −10V
+15V/ −10V
5.5V
675 mW (Note 5)
900 mW (Note 4)
−65˚C to +150˚C
Min
4.75
−7
Max
5.25
+12
Units
V
V
0
−40
+70
+85
˚C
˚C
−12
+12
V
260˚C
Electrical Characteristics (Notes 2, 3)
0˚C ≤ TA≤ 70˚C, 4.75V < VCC < 5.25V unless otherwise specified
Symbol
VOD1
Parameter
Conditions
Differential Driver Output
Min Typ
IO = 0
Max
Units
5
V
Voltage (Unloaded)
VOD2
(Figure 1)
Differential Driver Output
R = 50Ω; (RS-422) (Note 7)
Voltage (with Load)
∆VOD
R = 27Ω; (RS-485)
2
V
1.5
V
Change in Magnitude of Driver
Differential Output Voltage For
0.2
V
3.0
V
0.2
V
Complementary Output States
VOC
(Figure 1)
Driver Common Mode Output
R = 27Ω
Voltage
∆|VOC|
Change in Magnitude of Driver
Common Mode Output Voltage
For Complementary Output
States
VIH
Input High Voltage
VIL
Input Low Voltage
DI, DE,
RE , E
2
V
0.8
VCL
Input Clamp Voltage
IIN = −18 mA
−1.5
IIL
Input Low Current
VIL = 0.4V
−200
IIH
Input High Current
VIH = 2.4V
20
µA
IIN
Input
VCC = 0V or 5.25V
VIN = 12V
+1.0
mA
Current
DE = 0V
VIN = −7V
−0.8
mA
Differential Input Threshold
−7V ≤ VCM ≤ + 12V
+0.2
V
VTH
DO/RI, DO/RI
−0.2
µA
Voltage for Receiver
∆VTH
Receiver Input Hysteresis
VCM = 0V
VOH
Receiver Output High Voltage
IOH = −400 µA
VOL
Output Low Voltage
IOL = 16 mA (Note 7)
0.5
V
± 20
µA
55
mA
IOZR
RO
70
mV
2.7
V
OFF-State (High Impedance)
VCC = Max
Output Current at Receiver
0.4V ≤ VO ≤ 2.4V
RIN
Receiver Input Resistance
−7V ≤ VCM ≤ +12V
ICC
Supply Current
No Load
Driver Outputs Enabled
(Note 7)
Driver Outputs Disabled
35
mA
IOSD
Driver Short-Circuit
VO = −7V (Note 7)
−250
mA
Output Current
VO = +12V (Note 7)
+250
mA
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2
12
kΩ
Electrical Characteristics (Notes 2, 3)
(Continued)
0˚C ≤ TA≤ 70˚C, 4.75V < VCC < 5.25V unless otherwise specified
Symbol
IOSR
Parameter
Receiver Short-Circuit
Conditions
VO = 0V
Min Typ
Max
Units
−15
−85
mA
Output Current
Note 1: “Absolute Maximum Ratings” are those beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device should
be operated at these limits. The tables of “Electrical Characteristics” provide conditions for actual device operation.
Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless otherwise specified.
Note 3: All typicals are given for VCC = 5V and TA = 25˚C.
Note 4: Derate linearly at 5.56 mW/˚C to 650 mW at 70˚C.
Note 5: Derate linearly 6.11 mW/˚C to 400 mW at 70˚C.
Note 6: Differential - Input/Output bus voltage is measured at the noninverting terminal A with respect to the inverting terminal B.
Note 7: All worst case parameters for which note 7 is applied, must be increased by 10% for DS75176BT. The other parameters remain valid for −40˚C < TA
< +85˚C.
Switching Characteristics
VCC = 5.0V, TA = 25˚C
Symbol
Typ
Max
Units
tPLH
Driver Input to Output
Parameter
RLDIFF = 60Ω
Conditions
Min
12
22
ns
tPHL
Driver Input to Output
CL1 = CL2 = 100 pF
17
22
ns
tr
Driver Rise Time
RLDIFF = 60Ω
18
ns
tf
Driver Fall Time
CL1 =CL2 = 100 pF
18
ns
tZH
Driver Enable to Output High
CL = 100 pF (Figure 4 and Figure 6) S1
Open
29
100
ns
tZL
Driver Enable to Output Low
CL = 100 pF (Figure 4 and Figure 6) S2
Open
31
60
ns
tLZ
Driver Disable Time from Low
CL = 15 pF (Figure 4 and Figure 6) S2
Open
13
30
ns
tHZ
Driver Disable Time from High
CL = 15 pF (Figure 4 and Figure 6) S1
Open
19
200
ns
tPLH
Receiver Input to Output
CL = 15 pF (Figure 2 and Figure 7)
30
37
ns
tPHL
Receiver Input to Output
S1 and S2 Closed
32
37
ns
tZL
Receiver Enable to Output Low
CL = 15 pF (Figure 2 and Figure 8) S2
Open
15
20
ns
tZH
Receiver Enable to Output High
CL = 15 pF (Figure 2 and Figure 8) S1
Open
11
20
ns
tLZ
Receiver Disable from Low
CL = 15 pF (Figure 2 and Figure 8) S2
Open
28
32
ns
tHZ
Receiver Disable from High
CL = 15 pF (Figure 2 and Figure 8) S1
Open
13
35
ns
(Figure 3 and Figure 5)
3
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AC Test Circuits
DS008759-2
FIGURE 1.
DS008759-3
Note: S1 and S2 of load circuit are closed except as otherwise mentioned.
FIGURE 2.
DS008759-4
FIGURE 3.
DS008759-5
Note: Unless otherwise specified the switches are closed.
FIGURE 4.
Switching Time Waveforms
DS008759-6
FIGURE 5. Driver Propagation Delays and Transition Times
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4
Switching Time Waveforms
(Continued)
DS008759-7
FIGURE 6. Driver Enable and Disable Times
DS008759-8
Note: Differential input voltage may may be realized by grounding RI and pulsing RI between +2.5V and −2.5V
FIGURE 7. Receiver Propagation Delays
DS008759-9
FIGURE 8. Receiver Enable and Disable Times
Function Tables
DS75176B Transmitting
Inputs
Line
Outputs
RE
DE
DI
Condition
DO
DO
X
1
1
No Fault
0
1
X
1
0
No Fault
1
0
X
0
X
X
Z
Z
X
1
X
Fault
Z
Z
5
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Function Tables
(Continued)
DS75176B Receiving
Inputs
Outputs
RE
DE
RI-RI
RO
0
0
≥ +0.2V
1
0
0
≤ −0.2V
0
0
0
Inputs Open**
1
1
0
X
Z
X — Don’t care condition
Z — High impedance state
Fault — Improper line conditons causing excessive power dissipation in the driver, such as shorts or bus contention
situations
**This is a fail safe condition
Typical Application
DS008759-11
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6
Physical Dimensions
inches (millimeters) unless otherwise noted
Lit. # 103669
Molded Dual-In-Line Package (N)
Order Number DS75176BN or DS75176BTN
NS Package Number N08E
7
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DS75176B/DS75176BT Multipoint RS-485/RS-422 Transceivers
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