LMS75ALS176A
Differential Bus Transceivers
General Description
The LMS75ALS176A is a differential bus/line transceiver designed for bidirectional data communication on multipoint bus transmission lines.It is designed for balanced transmis-sion lines.It meets ANSI Standards TIA/EIA RS422-B,TIA/EIA RS485-A and ITU recommendation V.11and X.27.The LMS75ALS176A combines a TRI-STATE ™differential line driver and differential input receiver,both of which operate from a single 5.0V power supply.The driver and receiver have an active high and active low enable,respectively,that can be externally connected to function as a direction con-trol.The driver and receiver differential inputs are internally connected to form differential input/output (I/O)bus ports that are designed to offer minimum loading to bus whenever the driver is disabled or when V CC =0V.These ports feature wide positive and negative common mode voltage ranges,making the device suitable for multipoint applications in noisy environments.The LMS75ALS176A is available in a 8-Pin SOIC package.It is a drop-in socket replacement to TI’s SN75ALS176A.
Features
n Bidirectional transceiver
n Meet ANSI standard RS-485-A and RS-422-B n Low skew,2ns
n Low supply current,8mA (max.)
n Wide input and output voltage range n High output drive capacity ±60mA n Thermal shutdown protection n Open circuit fail-safe for receiver n Receiver input sensitivity ±200mV n Receiver input hysteresis 10mV (min.)n Single supply voltage operation,5V
n Glitch free power-up and power-down operation n Data rates up to 35Mbaud
n Pin and functional compatible with TI’s SN75ALS176A n
8-Pin SOIC
Applications
n Network hubs,bridges,and routers
n Point of sales equipment (ATM,barcode readers,…)n Industrial programmable logic controllers n High speed parallel and serial applications n
Multipoint applications with noisy environment
Typical Application
20047801
A Typical multipoint application is shown in the above figure.Terminating resistors,RT,are typically required but only located at the two ends of the cable.Pull up and pull down resistors maybe required at the end of the bus to provide failsafe biasing.The biasing resistors provide a bias to the cable when all drivers are in TRI-STATE,See National Application Note,AN-847for further information.
April 2003
LMS75ALS176A Differential Bus Transceivers
©2003National Semiconductor Corporation DS200478www.national
Connection Diagram
8-Pin SOIC
20047802
Top View
Ordering Information
Package Part Number Package Marking Transport Media
NSC Drawing
8-Pin SOIC
LMS75ALS176AM LMS75LS176A
Rail
M08A
LMS75ALS176AMX
2.5k Units Tape and Reel
Truth Table
DRIVER SECTION
RE DE DI A B X H H H L X H L L H X
L X
Z
Z RECEIVER SECTION
RE DE A-B RO L L ≥+0.2V H L L ≤−0.2V L H X X Z L
L
OPEN *
H
Note:*=Non Terminated,Open Input only
X =Irrelevant Z =TRI-STATE H =High level L =Low level
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Absolute Maximum Ratings
小区
自动售水机
(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 (Note 2)7V
Voltage Range at Any Bus Terminal
−7V to 12V Input Voltage,V IN (DI,DE,or RE)−0.3V to V CC +0.3V
Package Thermal Impedance,θJA 125C/W Junction Temperature (Note 3)150˚C Operating Free-Air Temperature Range,T A
0˚C to 70˚C Storage Temperature Range −65˚C to 150˚C
Soldering Information
Infrared or Convection (20sec.)235˚C ESD Rating (Note 4)
2KV Operating Ratings
Min Nom Max
Supply Voltage,V CC
4.75
5.0 5.25
V Voltage at any Bus Terminal (Separately or Common Mode)12−7
V
V IN or V IC
High-Level Input Voltage,V IH (Note 5)
2
V Low-Level Input Voltage,V IL (Note 5)
0.8
V Differential Input Voltage,V ID (Note 6)
±12
V
High-Level Output Driver,I OH −60mA Receiver,I OH −400
µA
Low-Level Output Driver,I OL 60mA Receiver,I OL
8
mA Electrical Characteristics
V CC =5V,T A =0˚C to 70˚C Symbol Parameter
Conditions
Typ
Max
Units
Driver Section V CL Input Clamp Voltage I I =−18mA −1.5V V O Output Voltage
I O =006V |V OD1|Differential Output Voltage I O =0 1.56
V |V OD2|Differential Output Voltage R L =100Ω,2V R L =54Ω
1.5 1.9
5V OD3Differential Output Voltage V TEST =−7V to 12V 1.5
5V ∆V OD
Change in Magnitude of Differential Output Voltage (Note 7)
R L =54Ωor 100Ω
±0.2
V
V OC Common-Mode Output Voltage
R L =54Ωor 100Ω3V −1
∆V OC
Change in Magnitude of Differential Output Voltage (Note 7)R L =54Ωor 100Ω
±0.2
V
I O Output Current Output Disabled (Note 8)V O =12V 1mA V O =−7V
−0.8I IH High-Level Input Current V IN =2.4V 20µA I IL Low-Level Input Current
V IN =0.4V −400µA
I OSD
Short-Circuit Output Current
V O =−7V −250mA
V O =0−150V O =V CC 250V O =8V
250
I CC
Supply Current No Load
Outputs Enabled or Disabled
4.88mA
Switching Characteristics t d (OD)
Differential Output Delay Time
R L =54Ω,C L =50pF
3
7
14
ns
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Electrical Characteristics
(Continued)
V CC =5V,T A =0˚C to 70˚C Symbol Parameter
Conditions
Min
Typ Max
Units t t (OD)Differential Output Transition Time R L =54Ω,C L =50pF
8ns t sk(p)Pulse Skew,(|t d(ODH -t d(ODL |)R L =54Ω,C L =50pF
03ns t sk(lim)Pulse Skew
R L =54Ω,C L =50pF (Note 9)
4ns t PZH Output Enable Time to High Level
R L =110Ω,C L =50pF 1850ns t PZL Output Enable Time to Low Level
R L =110Ω,C L =50pF 1835ns t PHZ Output Disable Time from High Level
R L =110Ω,C L =50pF 935ns t PLZ
Output Disable Time from Low Level
R L =110Ω,C L =50pF
10
17ns
Receiver Section V TH+Positive-Going Input Threshold Voltage V O =2.7V,I O =−0.4mA 0.2
V V TH−Negative-Going Input Threshold Voltage V O =0.5V,I O =8mA
−0.2V ∆V TH Hysteresis Voltage (V TH+-V TH−)
10
mV V CL Enable-Input Clamp Voltage I I =−18mA
1.5V V OH High-Level Output Voltage V ID =200mV,I OH =−400µA
2.7
V V OL Low-Level Output Voltage
V ID =−200mV,I OL =8mA
0.45V I OZ High-Impedance-State Output Current
V O =0.4V to 2.4V ±20
I IN Line Input Current Other Input =0V,(Note 5)V IN =12V 1mA V IN =−7V
−0.8I IH High-Level Enable-Input Current
V IH =2.7V 20µA I IL Low-Level Enable-Input Current
V IL =0.4V
−100
µA R IN Input Resistance
1220
k Ω
I OSR Short-Circuit Output Current V ID =200mV,V O =0V −15
−85mA I CC
Supply Current
No Load
Outputs Enabled or Disabled
4.88
mA
Switching Characteristics t PD Propagation Delay Time V ID =−1.5V to 1.5V,C L =15pF 8
1830
ns t sk(p)Pulse Skew (|t PLH -t PHL |)V ID =−1.5V to 1.5V,C L =15pF 2ns t sk(lim)Pulse Skew
R L =54Ω,C L =50pF (Note 9)7.5ns t PZH Output Enable Time to High Level
C L =15pF 535ns t PZL Output Enable Time to Low Level
C L =15pF 535ns t PHZ Output Disable Time from High Level
C L =15pF 2035ns t PLZ
Output Disable Time from Low Level
C L =15pF
10
17ns
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Electrical Characteristics
(Continued)
Note 1:Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.Operating Ratings indicate conditions for which the device is intended to be functional,but specific performance is not guaranteed.For guaranteed specifications and the test conditions,see the Electrical Characteristics Note 2:All voltage values,except differential I/O bus voltage,are with respect to network ground terminal.
Note 3:The maximum power dissipation is a function of T J(MAX),θJA ,and T A .The maximum allowable power dissipation at any ambient temperature is P D =(T J(MAX)-T A )/θJA .All numbers apply for packages soldered directly into a PC board.Note 4:ESD rating based upon human body model,100pF discharged through 1.5k Ω.Note 5:Voltage limits apply to DI,DE,RE pins.
Note 6:Differential input/output bus voltage is measured at the non-inverting terminal A with respect to the inverting terminal B.
Note 7:|∆V OD |and |∆V OC |are changes in magnitude of V OD and V OC ,respectively when the input changes from high to low levels.
Note 8:Applies to both power on and off (ANSI Standard RS-485conditions).Does not apply to TIA/EIA-422-B for a combined driver and receiver combination.Note 9:Skew limit is the maximum difference in propagation delay between any two channels of any two devices.
Typical Performance Characteristics
Driver High-Level Output Voltage vs.
High-Level Output Current
Driver Low-Level Output Voltage vs.
Low-Level Output Current
2004781220047813
Driver Differential Output Voltage vs.
Output Current Receiver High-Level Output Voltage vs.High-Level
Output Current
2004781420047815
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Typical Performance Characteristics
(Continued)
Receiver High-Level Output Voltage vs.
Free-Air Temperature
Receiver Low-Level Output Voltage vs.
Low-Level Output Current
2004781620047817
Receiver Low-Level Output Voltage vs.
Free-Air Temperature
微型麦克风
液压压力机Receiver Output Voltage vs.Enable Voltage 20047818
20047819
Receiver Output Voltage vs.Enable Voltage
20047820
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