DS16F95A [NSC]
TIA/EIA-485-A (RS-485) Extended Temperature Differential Bus Transceiver; TIA / EIA- 485 -A （ RS - 485 ）扩展温度差动总线收发器
| 型号： | DS16F95A |
| 厂家： | 
National Semiconductor |
| 描述： | TIA/EIA-485-A (RS-485) Extended Temperature Differential Bus Transceiver |
| 文件： | 总10页 (文件大小：347K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
November 11, 2008
DS16F95A
TIA/EIA-485-A (RS-485) Extended Temperature Differential
Bus Transceiver
The driver is designed to accommodate loads of up to 60 mA
of sink or source current and features positive and negative
General Description
The DS16F95A Differential Bus Transceiver is a monolithic
integrated circuit designed for bidirectional data communica-
tion on balanced multipoint bus transmission lines. The
transceiver conforms to both TIA/EIA-485-A and
TIA/EIA-422-B standards.
current limiting for protection from line fault conditions.
The device is offered in a rugged 8–lead Ceramic DIP pack-
age and is functional over the extended temperature range of
-55 °C to +180 °C.
The DS16F95A offers improved performance due to the use
of L-FAST bipolar technology. The L-FAST technology allows
for higher speeds and lower currents by minimizing gate delay
times. The DS16F95A features an extended temperature
range and is offered in a rugged ceramic package.
The DS16F95A combines a TRI-STATE® differential line driv-
er and a differential input line receiver, both of which operate
from a single 5.0V power supply. The driver and receiver have
an active Enable that can be externally connected to function
as a direction control. The driver differential outputs and the
receiver differential inputs are internally connected to form
differential input/output (I/O) bus ports that are designed to
offer minimum loading to the bus whenever the driver is dis-
abled or when VCC = 0V. These ports feature wide positive
and negative common mode voltage ranges, making the de-
vice suitable for multipoint applications in noisy environments.
Features
Extended temperature range to +180 °C
■
■
■
■
■
■
■
■
Conforms to TIA/EIA-485-A
Designed for multipoint transmission
Wide positive and negative I/O bus voltage range
Driver positive and negative current-limiting
High impedance receiver input
Receiver input hysteresis of 50 mV typical
Operates from single 5.0V supply
Reduced power consumption
■
■
Pin compatible with DS16F95/DS3695 and SN75176A
Available in a 8-lead ceramic DIP package
■
Logic Diagram
Function Tables
Driver
Driver Input
Enable
Outputs
DI
H
L
DE
H
A
H
L
B
L
H
H
Z
X
L
Z
Receiver
Differential Inputs
A–B
Enable
Output
RO
RE
30066720
L
H
VID ≥ 0.2V
L
L
VID ≤ −0.2V
0.2V > VID >-0.2V
X
L
X
Z
H
H = High Level
L = Low Level
X = Immaterial
Z = High Impedance (Off)
TRI-STATE® is a registered trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation
300667
www.national.com
Recommended Operating
Absolute Maximum Ratings (Note 1)
Conditions (Note 10)
If Military/Aerospace specified devices are required,
please contact the national Semiconductor Sales office/
Distributor for availability and specifications.
Min Typ Max
4.50 5.0 5.50
Units
V
Supply Voltage (VCC
Voltage at Any Bus Terminal
(Separately or Common Mode)
(VI or VCM −7.0
)
Storage Temperature Range
(Note 10)
−65°C to +175°C
)
+12
±12
V
V
Lead Temperature
(Soldering, 60 sec.)
Junction Temperature
Differential Input
Voltage (VID)
Output Current HIGH (IOH
Driver
300°C
+200°C
Maximum Package Power
Dissipation Capacity (J)
Above 25°C, derate J package
Supply Voltage
)
1300 mW
8.7 mW/°C
7.0V
−60
−400
mA
Receiver
μA
Output Current LOW (IOL
)
Input Voltage (Bus Terminal)
Enable Input Voltage
ESD Ratings
+15V/−10V
5.5V
(Note 11)
Driver
Receiver
60
16
mA
mA
°C
Operating Temperature (TA)
-55 +25 +180
Driver Electrical Characteristics (Notes 2, 3)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Min
VIH Input Voltage HIGH
Typ
Max
Units
DI, DE
2.0
V
V
VIL
Input Voltage LOW
0.8
-1.3
20
VIC
Input Clamp Voltage
Input Current HIGH
II = −18 mA
V
IIH
VI = 2.4V
μA
μA
V
IIL
Input Current Low
VI = 0.4V
-50
6.0
|VOD1
|VOD2
|
|
Differential Output Voltage
Differential Output Voltage
A-B, Figure 1
IO = 0 mA, No Load
RL = 100Ω
RL = 54Ω
3.6
2.9
2.6
2.0
1.5
V
Change in Magnitude of Differential
Output Voltage
Δ|VOD
|
RL = 54Ω or 100Ω,
(Note 4)
±0.4
3.0
V
V
V
Common Mode Output Voltage
(Note 5)
(A+B)/2, Figure 1
VOC
2.5
Change in Magnitude of Common
Mode Output Voltage (Note 4)
Δ|VOC
|
±0.2
1.5
IO
Output Current (Note 8) (Includes A or B, Output
Receiver II)
VO = +12V
VO = −7.0V
0.57
Disabled,
DE = 0.4V
mA
mA
-0.43
-0.8
IOS
Short Circuit Output Current
(Note 9)
A or B
VO = −7.0V
VO = 0V
-157
-115
112
137
-250
-150
150
250
VO = VCC
VO = +12V
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2
Driver Switching Characteristics (Note 2)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol
tDD
Parameter
Conditions
Min
Typ
Max
Units
Differential Output Delay Time
8.0
15
45
ns
RL = 60Ω, Figure 3
tTD
tZH
tZL
Differential Output Transition Time
Output Enable Time to High Level
Output Enable Time to Low Level
Output Disable Time from High Level
Output Disable Time from Low Level
8.0
15
25
25
20
20
30
50
50
80
80
ns
ns
ns
ns
ns
RL = 110Ω, Figure 4
RL = 110Ω, Figure 5
RL = 110Ω, Figure 4
RL = 110Ω, Figure 5
tHZ
tLZ
tLZL
Output Disable Time from Low Level with Load Load per Figure 4,
300
1.0
ns
ns
Resistor to GND
Timing per Figure 5
tSKEW
Skew (Pulse Width Distortion)
12
RL = 60Ω, Figure 3
Receiver Electrical Characteristics (Notes 2, 3)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol
VTH
Parameter
Differential Input High
Threshold Voltage
Conditions
VO = 2.7V, IO = −0.4 mA
Min
Typ
Max
Units
0.2
V
VTL
Differential Input Low
Threshold Voltage (Note 6)
Hysteresis (Note 7)
VO = 0.5V, IO = 8.0 mA
−0.2
V
VT+−VT−
VIH
VCM = 0V
RE
35
50
mV
V
Enable Input Voltage HIGH
Enable Input Voltage LOW
Enable Input Clamp Voltage
Input Current HIGH
2.0
VIL
0.8
-1.3
20
V
VIC
II = −18 mA
VIH = 2.7V
VIL = 0.4V
-0.8
1
V
IIH
μA
μA
V
IIL
Input Current LOW
-3
-50
VOH
VOL
Output Voltage HIGH (RO)
VID = 200 mV, IOH = −400 μA, Figure 2
2.5
-15
3.5
0.3
0.4
-46
0.2
0.57
-0.43
18
Output Voltage LOW (RO)
VID = −200 mV,
Figure 2
IOL = 8.0 mA
IOL = 16 mA
0.45
0.50
-85
V
IOS
IOZ
II
Short Circuit Output Current (RO)
VO = 0V, (Note 9)
mA
High Impedance State Output (RO) VO = 0.4V to 2.4V
±20
1.5
μA
Line Input Current (Note 8)
A or B,
Other Input = 0V
VI = +12V
VI = −7.0V
DE = 0.4V
mA
-0.8
22
RI
Input Resistance
A or B
12
kΩ
3
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Receiver Switching Characteristics (Note 2)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol
Parameter
Propagation Delay Time,
Conditions
VIN = 0V to +3.0V CL = 15 pF,
Figure 6
Min
Typ
Max
Units
tPLH
tPHL
10
19
50
ns
Low-to-High Level Output
Propagation Delay Time,
10
19
50
ns
High-to-Low Level Output
tZH
tZL
tHZ
Output Enable Time to High Level
Output Enable Time to Low Level
Output Disable Time from High Level
CL = 15 pF,
10
12
75
75
ns
ns
Figure 7
CL = 5.0 pF,
12
50
ns
Figure 7
tLZ
Output Disable Time from Low Level
Pulse Width Distortion (SKEW)
12
50
16
ns
ns
|tPLH−tPHL
|
Figure 6
1.0
Device Electrical Characteristics (Notes 2, 3)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol
ICC
Parameter
Conditions
DE = 2V, RE = 0.8V
Min
Typ
Max
Units
Supply Current (Total Package)
No Load,
21.5
16
28
25
All Inputs Open
Outputs Enabled
mA
ICCX
DE = 0.8V, RE = 2V
Outputs Disabled
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” provide conditions for actual device operation.
Note 2: Unless otherwise specified min/max limits apply across the -55°C to +180°C temperature range for the DS16F95A. All typical values are given for VCC
= 5V and TA = 25°C.
Note 3: All currents into the device pins are positive; all currents out of the device pins are negative. All voltages are referenced to ground unless otherwise
specified.
Note 4: Δ|VOD| and Δ|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.
Note 5: In TIA/EIA-422-B and TIA/EIA-485-A Standards, VOC, which is the average of the two output voltages with respect to ground, is called output offset
voltage, VOS
.
Note 6: 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 7: Hysteresis is the difference between the positive-going input threshold voltage, VT+, and the negative-going input threshold voltage, VT−
.
Note 8: Refer to TIA/EIA-485-A Standard for exact conditions.
Note 9: Only one output at a time should be shorted. Do not exceed maximum junction temperature recommendations. This device does not include thermal
shutdown protection.
Note 10: Lifetime expectations for continuous operation at above 150 °C for more than 1000 hours should be verified with National Semiconductor Reliability
Engineering. Reliability report available upon request.
Note 11: ESD Rating information: HBM >5kV A or B pin, all other pins > 1kV. MM > 600V A or B pin, all other pins > 50V, CDM >750V, IEC61000–4–2 (Power
On or Off) > 2kV A or B pin.
Parameter Measurement Information
30066702
FIGURE 1. Driver VOD and VOC (Note 15)
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4
30066703
FIGURE 2. Receiver VOH and VOL
30066704
30066705
tSKEW = |tPLHD–tPHLD
|
FIGURE 3. Driver Differential Output Delay and Transition Times (Notes 12, 14)
30066709
30066708
FIGURE 4. Driver Enable and Disable Times (tZH, tHZ) (Notes 12, 13, 14)
30066711
30066710
FIGURE 5. Driver Enable and Disable Times (tZL, tLZ, tLZL) (Notes 12, 13, 14)
5
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30066713
30066712
FIGURE 6. Receiver Propagation Delay Times (Notes 12, 13)
30066714
30066715
30066717
30066716
30066718
FIGURE 7. Receiver Enable and Disable Times (Notes 12, 13, 15)
Note 12: The input pulse is supplied by a generator having the following characteristics: PRR = 1.0 MHz, 50% duty cycle, tr ≤ 6.0 ns, tf ≤ 6.0 ns, ZO = 50Ω.
Note 13: CL includes probe and stray capacitance.
Note 14: DS16F95A Driver enable is Active-High.
Note 15: All diodes are 1N916 or equivalent.
Note 16: Testing at 20 pF assures conformance to 5 pF specification.
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6
minated at both ends in its characteristic impedance (typically
100 or 120 Ohms). The RS-485 network is a bi-directional half
duplex interface.
Functional Description
The Differential Line Driver levels shifts standard TTL/CMOS
levels to a differential voltage on the bus pins (A and B) that
conform to RS-485. The driver is enabled when the DE pin is
High. The driver is disabled when the DE pin is Low. The DI
and DE pins should be driven or tied to the desired state, do
not float. The differential driver is able to source and sink up
to 60mA of output current. Care should be taken that the driver
is not enabled into a fault condition where the package power
dissipation capacity is exceeded. The DS16F95A features
driver current limiting (see IOS specification) to protect from
certain line faults where the amount of power is limited. This
device is intended for use in rugged applications at elevated
temperatures. It does not include a Thermal Shutdown fea-
ture commonly found on RS-485 transceivers.
Being a multipoint bus, it is possible for all drivers to be dis-
abled when one or more receivers are enabled. In this case,
the receiver(s) is enabled when a valid differential voltage is
not present and its output state is unknown. A common solu-
tion is to provide external failsafe biasing to bias the line to a
known state such that the enabled receives will detect it cor-
rectly and idle with a static known state in this condition. See
AN-847 for a discussion on Failsafe biasing of differential
buses.
For extended temperature applications, maximum junction
temperature should be calculated. TJmax = TA + (ThetaJA)
(Power Dissipation). Theta JA is the reciprocal of the derate
term ( 1 / 8.7 mW/°C or 115 °C/W). Recommended maximum
junction temperature for short duration operation is 200°C.
See AN-336 for a discussion on thermal considerations.
The Differential line Receiver levels shifts the RS-485 levels
to standard TTL/CMOS levels. The receiver is enabled when
the RE pin is Low. The receiver is disabled when the RE pin
is High. The RE pin should be driven or tied to the desired
state, do not float.
For maximum performance, a few system / PCB recommen-
dations are: drive the logic inputs (DI, DE, RE) with rail-to-rail
levels. This will provide the maximum noise margins to the
thresholds. A clean supply is also desirable, a 0.1µF capacitor
is recommended to be placed near the VCC pin along with a
bulk capacitor. The use of power and ground planes is also
recommended. Stub lengths off the RS-485 interface should
be minimized to limit reflections. Typical interconnect
impedance is 100 Ohms.
Typical Application
A typical application is shown below. The RS-485 network
may be a simple point-to-point connection with two nodes or
a more complex one with up to 32 single unit load transceivers
as shown above. Stub lengths off the main line should be kept
as short as possible to minimize reflections. The line is ter-
30066719
Connection Diagram
8-Lead Dual-In-Line Package
30066701
7
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Physical Dimensions inches (millimeters) unless otherwise noted
8 Narrow Lead Ceramic Dual-In-Line Package (J)
Order Number DS16F95AJA
NS Package Number J08A
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8
Notes
9
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