Summary of Well Known Interface Standards

Transcription

1 Summary of Well Known Interface Standard FORWARD Deigning an interface between ytem i not a imple or traight-forward tak that mut be taken into account include data rate data format cable length mode of tranmiion termination bu common mode range connector type and ytem configuration Noting the number of parameter illutrate how complex thi tak actually i Additionally the interface compatibility with ytem from other manufacturer i alo critically important Thu the need for tandardized interface become evident Interface Standard reolve both the compatibility iue and eae the deign through the ue of non-cutom tandardized Driver and Receiver INTRODUCTION Thi application note provide a hort ummary of popular Interface Standard In mot cae a table of the major electrical requirement and a typical application i illutrated Interface Standard from the following tandardization organization are covered in thi application note TIA EIA Telecommunication Indutry Aociation Electronic Indutry Aociation CCITT International Telegraph and Telephone Conultative Committee now replaced by the ITU International Telecommunication Union MIL-STD United State Military Standard FED-STD Federal Telecommunication Standard Committee Other elected interface tandard There are two baic mode of operation for line driver (generator) and receiver The two mode are Unbalanced (Single-ended) and Balanced (Differential) UNBALANCED (SINGLE-ENDED) DATA TRANSMISSION Unbalanced data tranmiion ue a ingle conductor with a voltage referenced to ignal ground (common) to denote logical tate In unbalanced communication only one line i witched The advantage of unbalanced data tranmiion i when mulitple channel are required a common ground can be ued (ee Figure 1 ) Thi minimize cable and connector ize which help to minimize ytem cot The diadvantage of unbalanced data tranmiion i in it inability to reliably end data in noiy environment Thi i due to very limited noie margin The ource of ytem noie can include externally induced noie cro talk and ground potential difference National Semiconductor Application Note 216 John Goldie January 1996 TL F FIGURE 1 Unbalanced Data Tranmiion- 3 Channel 4 Line BALANCED (DIFFERENTIAL) DATA TRANSMISSION Balanced data tranmiion require two conductor per ignal In balanced communication two line are witched The logical tate are referenced by the difference of potential between the line not with repect to ground Thi fact make differential driver and receiver ideal for ue in noiy environment (See Figure 2) Differential data tranmiion nullifie the effect of coupled noie and ground potential difference Both of thee are een a common mode voltage (een on both line) not differential and are rejected by the receiver In contrat to unbalanced driver mot balanced driver feature fat tranition time allowing for operation at higher data rate TL F FIGURE 2 Balanced Data Tranmiion- 3 Channel 7 Line and Ground Summary of Well Known Interface Standard AN-216 C1996 National Semiconductor Corporation TL F 5855 RRD-B30M36 Printed in U S A http www national com

2 TIA EIA DATA TRANSMISSION STANDARDS The Electronic Indutry Aociation (EIA) and the Telecommunication Indutry Aociation (TIA) are indutry trade aociation that have developed tandard to implify interface in data communication ytem The tandard are intended for ue in Data Terminal Equipment Data Circuitterminating Equipment (DTE DCE) Interface The claic example of the DTE DCE interface i the terminal to modem erial interface However the tandard are not limited to ue in DTE DCE interface alone In fact many of the tandard are commonly ued in a wide variety of application Example include Hard Dik Drive Interface Factory Control Bue and generic I O Bue Previouly EIA labeled the tandard with the prefix RS which tood for recommended tandard Thi ha been replaced with TIA EIA to help in identifying the ource of the tandard The letter uffix repreent the reviion level of the tandard For example TIA EIA-232-E repreent the fifth reviion of RS- 232 TIA EIA Data Tranmiion Standard cover the following area Complete Interface Standard Electrical Only Standard and Signal Quality Standard Complete tandard define functional mechanical and electrical pecification Electrical only tandard a their name implie only define electrical pecification They are intended to be referenced by complete tandard Signal Quality Standard define term and method for meauring ignal quality Example of each type are lited below Complete DTE DCE Interface Standard EIA TIA-232-E EIA TIA-530-A EIA TIA-561 EIA TIA-574 TIA EIA-613 Electrical Only Standard Unbalanced Standard EIA TIA-232-E (Section 2) TIA EIA-423-B (draft) EIA TIA-562 Balanced Standard TIA EIA-422-B (draft) EIA-485 TIA EIA-612 Signal Quality Standard EIA-334-A EIA-363 EIA-404-A TIA EIA UNBALANCED (SINGLE-ENDED) STANDARDS EIA TIA-232-E (RS-232) EIA TIA-232-E i the oldet and mot widely known DTE DCE Interface Standard It i a complete tandard pecifying the mechanical (connector()) electrical (driver receiver characteritic) and functional (definition of circuit) requirement for a erial binary DTE DCE Interface Under the electrical ection the tandard pecifie an unbalanced unidirectional point-to-point interface The driver feature a controlled lew rate thi allow the cable to be een a a lumped load rather than a tranmiion line Thi i due to the fact that the driver tranition time i ubtantially greater than the cable delay (velocity c length) The maximum capacitive load een by the driver i pecified at pf The tandard allow for operation up to 20 kbp (19 2 kbp) For higher data rate EIA TIA-562 or TIA EIA-423-B are recommended Figure 3 illutrate a typical application and Table I lit the major electrical requirement Key Feature of the tandard are Single-Ended Point-to-Point Interface Large Polar Driver Output Swing Controlled Driver Slew Rate Fully Defined Interface 20 kbp Maximum Data Rate TABLE I EIA TIA-232-E Major Electrical Specification Limit Unit Driver Loaded Output Voltage (3 kx) Driver Open Circuit Voltage Driver Short Circuit Current Maximum Driver Slew Rate Driver Output Reitance (Power Off) Receiver Input Reitance Maximum Receiver Input Voltage Receiver Threhold t l 5 0V l l 25V l l 100 ma l 30 V m t 300X 3 kx to7kx g25v g3v FIGURE 3 Typical EIA TIA-232-E Application TL F http www national com 2

3 TIA EIA-423-B TIA EIA-423-B while imilar to EIA TIA-232-E feature a reduced driver output wing and upport higher data rate Thi tandard pecifie an unbalanced driver and a balanced receiver It i an electrical tandard pecifying driver and receiver requirement only The receiver requirement are identical to the receiver requirement pecified in TIA EIA-422-B tandard TIA EIA-423-B i intended to be referenced by complete tandard uch a EIA TIA-530-A TIA EIA-423-B pecifie a unidirectional multidrop (up to ten receiver) interface Advantage over EIA TIA-232-E include multiple receiver operation fater data rate and common power upplie (typically g5v) Figure 4 illutrate a typical application and Table II lit the major electrical requirement Note RS-423-A i currently being revied once approved it will become TIA EIA-423-B Thi i expected by the end of 1993 Thi ection i baed on the propoed draft tandard TL F FIGURE 4 Typical TIA EIA-423-B Application Key Feature of the tandard are Unbalanced Driver and Balanced Receiver Multi-Drop (multiple receiver) Wave Shape Control (Driver Output) g7v Receiver Common Mode Range g200 mv Receiver Senitivity 100 kbp Maximum Data Rate ( 40 feet) 4000 Foot Maximum Cable Length ( 1 kbp) TABLE II TIA EIA-423-B Major Electrical Specification Driver Output Voltage (450X Load) Driver Open Circuit Voltage Driver Short Circuit Current Tranition Time Driver Output Leakage Current Receiver Specification Limit Unit t l3 6Vl t l4 0Vl l6 0Vl l150 mal Controlled l100 mal See TIA EIA-422-B EIA TIA-562 EIA TIA-562 i a new electrical tandard which i very imilar to EIA TIA-232-E but upport higher data rate (64 kbp) It i an electrical only tandard which i intended to be referenced by complete tandard uch a EIA TAI-561 EIA TIA-562 pecifie an unbalanced unidirectional point-to-point interface Thi tandard upport interoperability with EIA TIA-232-E device Figure 5 illutrate a typical application and Table III lit the major electrical requirement TL F FIGURE 5 Typical EIA TIA-562 Application Key Feature of the tandard are Unbalanced Driver and Receiver Point-to-Point Inter-Operability with EIA TIA-232-E Device 64 kbp Maximum Data Rate TABLE III EIA TIA-562 Major Electrical Specification Limit Unit Driver Loaded Output Voltage (Min Level) t l 3 3V l Driver Open Circuit Output Voltage l 13 2V l Driver Loaded Output Voltage (3 kx) Driver Short Circuit Current Driver Tranition Time Maximum Driver Slew Rate Driver Output Reitance (Power Off) Receiver Input Reitance Maximum Receiver Input Voltage Receiver Threhold t l 3 7V l l 60 ma l Controlled 30 V m t 300X 3 kx to7kx g25v g3v 3 http www national com

4 TIA EIA BALANCED (DIFFERENTIAL) STANDARDS TIA EIA-422-B TIA EIA-422-B i an electrical tandard pecifying a balanced driver and balanced receiver The receiver requirement are identical to the receiver requirement pecified in TIA EIA-423-B Thi tandard pecifie a unidirectional ingle driver multiple receiver terminated balanced interface Figure 6 illutrate a point-to-point typical application with termination located at the receiver input (end of cable) Figure 7 illutrate a fully loaded TIA EIA-422-B interface Again termination i located at the end of the cable alo tub length hould be minimized to limit reflection Table IV lit the major electrical requirement of the TIA EIA-422-B Standard NOTE RS-422-A i currently being revied once approved it will become TIA EIA-422-B Thi i expected by the end of 1993 Thi ection i baed on the propoed draft tandard Key Feature of the tandard are Balanced Interface Multi-Drop (Multiple Receiver Operation) 10 Mbp Maximum Data Rate ( 40 feet) 4000 Foot Maximum Cable Length ( 100 kbp) TABLE IV TIA EIA-422-B Major Electrical Specification Driver Open Circuit Voltage Driver Loaded Output Voltage Balance of Loaded Output Voltage Driver Output Offet Voltage Balance of Offet Voltage Driver Short Circuit Current Driver Leakage Current Driver Output Impedance Receiver Input Reitance Receiver Threhold Receiver Internal Bia Maximum Receiver Input Current Receiver Common Mode Range Receiver Operating Differential Range Maximum Differential Input Voltage Limit Unit l 10V l t l 2 0V l 400 mv 3 0V 400 mv l150 ma l l 100 ma l 100X t 4kX g200 mv 3 0V 3 25 ma g7v (g10v) g200 mv to g6v g12v FIGURE 6 Typical TIA EIA-422-B Point-to-Point Application TL F FIGURE 7 Typical TIA EIA-422-B Multidrop Application TL F http www national com 4

5 EIA-485 EIA-485 i an electrical tandard pecifying balanced driver and receiver It provide all the advantage of TIA EIA- 422-B along with upporting multiple driver operation EIA- 485 i the only TIA EIA tandard that allow for multiple driver operation Thi fact allow for multipoint (party line) configuration The tandard pecifie a bi-directional (half duplex) multipoint interface Figure 8 illutrate a typical multipoint application and Table V lit the major electrical requirement Key Feature are Balanced Interface Multipoint Operation Operation From a Single a5v Supply b7v to a12v Bu Common Mode Range Up to 32 Tranceiver Load (Unit Load) 10 Mbp Maximum Data Rate ( 40 feet) 4000 Foot Maximum Cable Length ( 100 kbp) TABLE V EIA-485 Major Electrical Specification Limit Unit Driver Open Circuit Voltage Driver Loaded Output Voltage Balance of Driver Loaded Output Voltage Maximum Driver Offet Voltage Balance of Driver Offet Voltage Driver Tranition Time Driver Short Circuit Current (b7v to a12v) Receiver Threhold Maximum Bu Input Current a12v b7v l 6 0V l t l 1 5V l l 200 mv l 3 0V l 200 mv l 30% Tui l 250 ma l g200 mv 1 0 ma 0 8 ma FIGURE 8 Typical EIA-485 Application TL F http www national com

6 TIA EIA BALANCED (DIFFERENTIAL) STANDARDS TIA EIA-612 TIA EIA-612 i an electrical tandard pecifying a balanced driver and balanced receiver Thi tandard pecifie data rate up to 52 Mbp uing ECL technology Thi tandard pecifie a unidirectional point-to-point interface Figure 9 illutrate a typical application with termination located at the receiver input (end of cable) Table VI lit the major electrical requirement of the TIA EIA-612 Standard Thi Standard i referenced by TIA EIA-613 and together implement a HSSI (High Speed Serial Interface) TABLE VI TIA EIA-612 Major Electrical Specification Driver Open Circuit Voltage Driver Loaded Output Voltage Balance of Loaded Output Voltage Driver Output Offet Voltage Balance of Offet Voltage Driver Short Circuit Current Receiver Threhold Receiver Input Range Receiver Input Current Maximum Differential Input Voltage Limit and Unit l1 5V l t l590 mv l l100 mv l 0V and t b1 6V l100 mvl 50 ma g150 mv b0 5V to b2 0V 350 ma 1 5V OTHER EIA TIA STANDARDS EIA-334-A EIA-334-A define ignal quality term for ynchronou erial DTE DCE interface Thi tandard i referenced by the complete ynchronou tandard EIA-363 EIA-363 define ignal quality term for non-ynchronou erial DTE DCE interface Thi tandard i referenced by the complete non-ynchronou tandard EIA-366-A EIA-366-A define a complete interface between Data Terminal Equipment (DTE) and Automatic Calling Equipment (ACE) The electrical requirement for the driver and receiver are identical to thoe in EIA TIA-232-E EIA-404-A EIA-404-A define ignal quality for tart-top non-ynchronou DTE DCE interface EIA-408 EIA-408 define a complete parallel interface between Data Terminal Equipment (DTE) and Numerical Control Equipment (NCE) The interface i limited to hort ditance and utilize TTL type driver and receiver The driver are required to ink 48 ma with a VOL of 0 4V and ource 1 2 ma with a V OH of t 2 4V Short circuit protection i alo recommended TL F FIGURE 9 Typical TIA EIA-612 and TIA EIA-644 Point-to-Point Application TIA EIA-644 TIA EIA-644 i an electrical tandard pecifying a balanced driver and a balanced receiver() Thi tandard pecifie data rate up to 655 Mbp uing LVDS (Low Voltage Differential Signaling) technology Thi tandard pecifie a unidirectional point-to-point interface Multiple receiver are upported under certain application limitation Figure 9 illutrate the typical point-to-point application with termination (required) located at the receiver input (end of cable) Table VII lit the major electrical requirement of the TIA EIA-644 Standard Thi Standard i intended to be referenced by other tandard which pecify the complete interface TABLE VII TIA EIA-644 Major Electrical Specification Limit and Unit Driver Output Voltage 247 mv Vdiff 454 mv Driver Offet Voltage 1 125V V OS Driver Short Circuit Current 24 ma Receiver Threhold g100 mv Receiver Input Range 0V to a2 4V Receiver Differential Input Range 100 mv to 600 mv Receiver Input Current g20 ma http www national com 6

7 EIA-449 EIA-449 i a complete tandard pecifying a general purpoe DTE DCE erial interface It i a complete tandard pecifying the function of the line (Data Timing Control) and a 37 poition connector Thi tandard reference TIA EIA-422-B and TIA EIA-423-B tandard for line driver and receiver requirement and characteritic The tandard upport data rate up to 2 Mbp The ize of the pecified connector ha prevented wide pread acceptance of thi tandard New deign are utilizing EIA TIA-530-A intead of EIA-449 EIA TIA-530-A EIA TIA-530-A i a complete tandard pecifying a high peed DTE DCE erial interface It i a complete tandard pecifying the function of the line (Data Timing Control) and a 25 poition connector Thi tandard reference TIA EIA-422-B and TIA EIA-423-B tandard for line driver and receiver requirement and characteritic The tandard upport data rate up to 2 1 Mbp Two connector option are provided a common 25 poition D connector and a maller 26 poition connector Note Connector pinout difference exit between EIA-530 and EIA TIA- 530-A EIA TIA-561 EIA TIA-561 i a complete tandard pecifying a non-ynchronou DTE DCE erial interface It i a complete tandard pecifying the function of the line (Data Timing Control) and a mall 8 poition connector (MJ8) Thi tandard reference EIA TIA-562 tandard for line driver and receiver requirement and characteritic The tandard upport data rate up to 38 4 kbp EIA TIA-574 EIA TIA-574 i a complete tandard pecifying a non-ynchronou DTE DCE erial interface It i a complete tandard pecifying the function of the line (Data Timing Control) and a 9 poition connector Thi tandard reference EIA TIA-562 tandard for line driver and receiver requirement and characteritic The tandard upport data rate up to 38 4 kbp TIA EIA-613 TIA EIA-613 i a complete tandard pecifying a general purpoe DTE DCE interface for data rate up to 52 Mbp Thi tandard pecifie functional and connector pecification and reference TIA EIA-612 for electrical characteritic Together TIA EIA-612 and TIA EIA-613 implement a HSSI interface CCITT STANDARDS (ITU) CCITT (International Telegraph and Telephone Conultative Committee) create and maintain tandard which are intended to help tandardize international telecommunication ervice Thee tandard are recommended technical practice and approache however in ome countrie they can be conidered mandatory CCITT review it tandard on a 4 year cycle Many of the Interface tandard are located in volume eight of the CCITT V erie Thi volume i titled Data Communication over the Telephone Network Some of the Interface tandard are alo covered in the X erie The CCITT prefix ha been replaced by ITU for International Telecommunication Union and the term CCITT will eventually be phaed out A cro reference i provided in Table VIII TABLE VIII V and X Serie Cro Reference V Serie X Serie V 10 X 26 V 11 X 27 Recommendation V 10 Recommendation V 10 define the electrical characteritic for an unbalanced interface Thi recommendation pecifie an unbalanced driver and a balanced receiver With the exception of generator (driver) open circuit output voltage pecification V 10 generator (driver) requirement are very imilar to the TIA EIA-423-B tandard In V 10 the driver i loaded with a 3 9 kx reitor to ground while in the TIA EIA-423-B tandard the driver i unloaded The V 10 receiver i pecified with g300 mv threhold while the TIA EIA- 423-B receiver upport a tighter pecification of g200 mv Other maller difference alo exit Therefore for exact condition and requirement conult the repective tandard Recommendation V 11 Recommendation V 11 define the electrical characteritic for a balanced Interface V 11 pecifie a balanced driver and balanced receiver With the exception of generator (driver) open circuit output voltage pecification V 11 generator (driver) requirement very imilar to the TIA EIA-422-B 7 http www national com

8 tandard V 11 require a 3 9 kx differential load for the driver open circuit output while TIA EIA-422-B tet condition require no load (open circuit) The Receiver pecification are alo very imilar with the exception of the input threhold pecification Recommendation V 11 require threhold of g300 mv while TIA EIA-422-B require a tighter pecification of g200 mv Other maller difference alo exit Therefore for exact condition and requirement conult the repective tandard Recommendation V 24 Recommendation V 24 define the function of interchange circuit for DTE DCE interface Circuit cla (Data Timing or Control) direction and definition are all defined in thi recommendation V 24 i intended to be referenced by other recommendation Recommendation V 28 Recommendation V 28 define the electrical characteritic for an unbalanced Interface Thi tandard pecifie driver output and receiver input characteritic The tandard i very imilar to the Electrical ection (2) of the EIA TIA-232-E tandard The one notable exception in the generator (driver) requirement i the lew rate pecification The EIA TIA-232-E lower limit for lew rate i 3 V m ( 20 kbp) (meaured between the a3v and b3v level) while in V 28 the lower limit i 4 V m ( 20 kbp) Both tandard pecify the ame upper limit of 30 V m under light loading condition EIA TIA-232-E define the complete interface while V 28 only define the electrical ection of EIA TIA-232-E The complete interface tandard i covered by CCITT Recommendation V 28 (electrical) V 24 (functional) and ISO (mechanical) For complete pecification refer to CCITT Recommendation V 28 Recommendation V 35 Recommendation V 35 i actually a modem tandard that alo define a balanced interface While many application operate at data rate ubtantially higher than 48 kbp (typically l 1 Mbp) the interface i only defined to operate up to 48 kbp For low peed control line the tandard recommend the ue of V 28 generator (driver) and receiver For ue on high peed data and timing line the tandard recommend the ue of unique V 35 balanced generator (driver) The driver feature a mall wing of g0 55V acro a termination load of 100X The generator i alo pecified to have polar wing around ground yielding a 0V offet voltage Mot implementation ue differential current mode driver with external reitor to implement V 35 balanced generator V 35 ha been recinded and V 10 and V 11 generator are recommended a replacement US MILITARY STANDARDS MIL STD 188C (Low Level) Military Standard 188C (MIL-STD-188C) i imilar to EIA TIA-232-E in the fact that it pecifie an unbalanced point-to-point interface However the driver requirement are lightly different The driver i till required to develop a l 5V l level The maximum driver output level i pecified at l 7V l and the match between V OL and V OH level mut be within 10% of each other The driver lew rate i pecified to be between 5% and 15% of the applicable modulation rate Mot driver require an external capacitor to control the lew rate Figure 10 illutrate a typical application and Table IX lit the major electrical pecification of MIL-STD- 188C TABLE IX MIL-STD-188C Major Electrical Specification Unloaded Driver Output Level Driver Output Reitance (Power ON) (I O 10 ma) Driver Output Short Circuit Current Driver Output Slew Rate Receiver Input Reitance Receiver Input Threhold Limit Unit g5v Min g7v Max 100X Max g100 ma 5% to 15% of Modulation Rate t6kx g100 ma FIGURE 10 Typical MIL-STD-188C Application TL F http www national com 8

9 TL F FIGURE 11 MIL STD A Unbalanced Typical Application MIL STD A Military Standard pecifie four different interface three balanced and one unbalanced The balanced interface are divided into three type two of which are voltage mode and one of which i current mode See Figure and 13 Voltage mode type 1 define an interface for data rate up to 100 kbp An additional requirement of type 1 i a polar (around ground) output wing Thi provide a zero offet output voltage Voltage mode type 2 driver operate up to 10 Mbp and require the ame parameter a EIA TIA-422-A driver Additionally type 2 driver can have an output offet up to 3V Current mode type 3 driver operate beyond 10 Mbp The receiver pecified for type 1 2 balanced and unbalanced driver are identical to the receiver pecified in TIA EIA-422-B and TIA EIA-423-B tandard TL F FIGURE 12 MIL STD A Balanced Type 1 Typical Application TL F FIGURE 13 MIL STD A Balanced Type 2 Typical Application MIL STD 1397 Military Standard 1397 pecifie two interface Thee are termed low and fat The low interface operate up to 42 kbp while the fat interface i defined to operate up to 250 kbp Comparator and or dicrete component are ued to implement driver and receiver FEDERAL TELECOMMUNICATIONS STANDARDS Federal Standard are from the Federal Telecommunication Standard Committee which i an adviory committee that adopt TIA EIA interface tandard FED STD 1020A The FEDSTD 1020A i identical to TIA EIA-423-B It i intended for United State non-military government ue FED STD 1030A The FEDSTD 1030A i identical to TIA EIA-422-B It i intended for United State non-military government ue OTHER STANDARDS IEEE488 The IEEE (Intitute of Electrical and Electronic Engineer) alo ha a tandard developing arm Generally the IEEE tandard deal with complete Bu pecification IEEE488 i a complete Bu tandard covering the electrical mechanical and functional pecification of a parallel intrumentation bu The bu i commonly ued for communication of lab tet equipment and machinery control The tandard allow for 15 device to be connected together over cable length up to 60 feet The tandard define 16 line compoed of 3 control 5 management and 8 data line The major electrical pecification are ummarized in Table X TABLE X Major IEEE488 Electrical Requirement Symbol Condition Min Max Unit V OH Driver Output Voltage I OH eb5 2 ma 2 4 V V OL Driver Output Voltage I OL e 48 ma 0 4 V I OZ Driver Output Leakage Current V O e 2 4V g40 ma I OH Driver Output Current Open Collector V O e 5 25V 250 ma V IH Receiver Input Voltage 2 0 V V IL Receiver Input Voltage 0 8 V I IH Receiver Input Current V IN e 2 4V 40 ma I IL Receiver Input Current V IN e 0 4V b1 6 ma I CL Receiver Clamp Current V IN eb1 5V 12 ma RL 1 Termination Reitor V CC e 5V g5% X RL 2 Termination Reitor V e GND X 9 http www national com

10 GA IBM pecification GA pecifie the electrical characteritic format of information and the control cheme of an unbalanced interface Thi interface i mainly ued on equipment and allow up to 10 I O port Thi unbalanced interface employ 95X terminated coax cable Driver normally feature open-emitter deign and hort-circuit limiting Receiver normally feature hyterei to prevent output ocillation for low riing input in noiy environment Care hould be taken to limit cable length uch that noie i limited to le than 400 mv Figure 14 illutrate a typical application and Table XI lit the major electrical requirement TL F FIGURE 14 GA Typical Application TABLE XI Major Electrical Requirement of GA Symbol Condition Min Max Unit V OH Driver Output Voltage I OH e 123 ma 7 V V OH I OH e 30 ma 5 85 V V OH I OH e 59 3 ma 3 11 V V OL I OL eb240 ma 0 15 V V IH Receiver Input Threhold 1 7 V V IL 0 7 V I IH Receiver Input Current V IN e 3 11V b0 42 ma I IL V IN e 0 15V 0 24 ma Receiver Input Voltage Range V IN Power ON b V V IN Power OFF b V R IN Receiver Input Impedance 0 15V V IN 3 9V 7 4 kx I IN Receiver Input Current V IN e 0 15V 240 ma Z O Cable Impedance X R O Cable Termination PD 390 mw X Noie (Signal and Ground) 400 mv CONCLUSION Thi application note provide a brief overview of variou interface tandard from everal tandardization organization It i only intended to point out the major requirement of each tandard and to illutrate a typical application When electing or deigning a tandardized interface it i highly recommended to carefully review the complete tandard Standard can be ordered from the repective organization or from Global Engineering Document 2805 McGraw Avenue P O Box Irvine CA USA (800) http www national com 10

11 11 http www national com

12 AN-216 Summary of Well Known Interface Standard LIFE SUPPORT POLICY NATIONAL S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION A ued herein 1 Life upport device or ytem are device or 2 A critical component i any component of a life ytem which (a) are intended for urgical implant upport device or ytem whoe failure to perform can into the body or (b) upport or utain life and whoe be reaonably expected to caue the failure of the life failure to perform when properly ued in accordance upport device or ytem or to affect it afety or with intruction for ue provided in the labeling can effectivene be reaonably expected to reult in a ignificant injury to the uer National Semiconductor National Semiconductor National Semiconductor National Semiconductor Corporation Europe Hong Kong Ltd Japan Ltd 1111 Wet Bardin Road Fax a49 (0) th Floor Straight Block Tel Arlington TX europe upport nc com Ocean Centre 5 Canton Rd Fax Tel 1(800) Deutch Tel a49 (0) Timhatui Kowloon Fax 1(800) Englih Tel a49 (0) Hong Kong Fran ai Tel a49 (0) Tel (852) http www national com Italiano Tel a49 (0) Fax (852) National doe not aume any reponibility for ue of any circuitry decribed no circuit patent licene are implied and National reerve the right at any time without notice to change aid circuitry and pecification