8线总线收发器SN74LVCC3245的原理及应用
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74LVC245A; 74LVCH245AOctal bus transceiver; 3-stateRev. 9 — 11 September 2018Product data sheet1. General descriptionThe 74LVC245A; 74LVCH245A are 8-bit transceivers featuring non-inverting 3-state buscompatible outputs in both send and receive directions. The device features an output enable(OE) input for easy cascading and a send/receive (DIR) input for direction control. OE controls theoutputs so that the buses are effectively isolated.Inputs can be driven from either 3.3 V or 5 V devices. When disabled, up to 5.5 V can be applied tothe outputs. These features allow the use of these devices in mixed 3.3 V and 5 V applications.The 74LVCH245A bus hold on data inputs eliminates the need for external pull-up resistors to holdunused inputs.2. Features and benefits• 5 V tolerant inputs/outputs for interfacing with 5 V logic•Wide supply voltage range from 1.2 V to 3.6 V•CMOS low-power consumption•Direct interface with TTL levels•Inputs accept voltages up to 5.5 V•High-impedance when V CC = 0 V•Bus hold on all data inputs (74LVCH245A only)•Complies with JEDEC standard:•JESD8-7A (1.65 V to 1.95 V)•JESD8-5A (2.3 V to 2.7 V)•JESD8-C/JESD36 (2.7 V to 3.6 V)•ESD protection:•HBM JESD22-A114F exceeds 2000 V•MM JESD22-A115B exceeds 200 V•CDM JESD22-C101E exceeds 1000 V•Specified from -40 °C to +85 °C and -40 °C to +125 °C3. Ordering information4. Functional diagram5. Pinning information5.1. Pinning74LVC245A 74LVCH245ADIR V CC A0OE A1B0A2B1A3B2A4B3A5B4A6B5A7B6GND B7001aak2921234567891012111413161518172019Fig. 3.Pin configuration SOT163-1 (SO20),SOT339-1 (SSOP20) and SOT360-1 (TSSOP20)001aak29374LVC245A 74LVCH245AT ransparent top viewB6A6A7B5A5B4A4B3A3B2A2B1A1B0A0OE G N D B 7D I R V C C9128137146155164173182191011120terminal 1 index areaGND (1)(1) This is not a supply pin. The substrate is attached to this pad using conductive die attach material. There is no electrical or mechanical requirement to solder this pad. However, if it is soldered, the solder land should remain floating or be connected to GND.Fig. 4.Pin configuration SOT764-1 (DHVQFN20)5.2. Pin description6. Functional descriptionTable 3. Function selectionH = HIGH voltage level; L = LOW voltage level; X = don’t care; Z = high impedance OFF-state.7. Limiting valuesTable 4. Limiting valuesIn accordance with the Absolute Maximum Rating System (IEC 60134). Voltages are referenced to GND (ground = 0 V).[1]The minimum input voltage ratings may be exceeded if the input current ratings are observed.[2]The output voltage ratings may be exceeded if the output current ratings are observed.[3]For SO20 packages: above 70 °C derate linearly with 8 mW/K.For (T)SSOP20 packages: above 60 °C derate linearly with 5.5 mW/K.For DHVQFN20 packages: above 60 °C derate linearly with 4.5 mW/K.8. Recommended operating conditions9. Static characteristicsTable 6. Static characteristicsAt recommended operating conditions. Voltages are referenced to GND (ground = 0 V).[1]All typical values are measured at V CC = 3.3 V (unless stated otherwise) and T amb = 25 °C.[2]The bus hold circuit is switched off when V I ˃ V CC allowing 5.5 V on the input terminal.[3]For I/O ports the parameter I OZ includes the input leakage current.[4]Valid for data inputs of bus hold parts only (74LVCH245A). Note that control inputs do not have a bus hold circuit.[5]The specified sustaining current at the data input holds the input below the specified V I level.[6]The specified overdrive current at the data input forces the data input to the opposite input state.10. Dynamic characteristicsTable 7. Dynamic characteristicsVoltages are referenced to GND (ground = 0 V). For test circuit see Fig. 7.[1]Typical values are measured at T amb = 25 °C and V CC = 1.2 V, 1.8 V, 2.5 V, 2.7 V and 3.3 V respectively.[2]t pd is the same as t PLH and t PHL.t en is the same as t PZL and t PZH.t dis is the same as t PLZ and t PHZ.[3]Skew between any two outputs of the same package switching in the same direction. This parameter is guaranteed by design.[4]C PD is used to determine the dynamic power dissipation (P D in μW).P D = C PD × V CC2 × f i × N + Σ(C L × V CC2 × f o) where:f i = input frequency in MHz; f o = output frequency in MHzC L = output load capacitance in pFV CC = supply voltage in VoltsN = number of inputs switchingΣ(C L × V CC2 × f o) = sum of the outputs.10.1. Waveforms and test circuit11. Package outlineSO20: plastic small outline package; 20 leads; body width 7.5 mm SOT163-1Fig. 8.Package outline SOT163-1 (SO20)SSOP20: plastic shrink small outline package; 20 leads; body width 5.3 mm SOT339-1Fig. 9.Package outline SOT339-1 (SSOP20)TSSOP20: plastic thin shrink small outline package; 20 leads; body width 4.4 mm SOT360-1Fig. 10.Package outline SOT360-1 (TSSOP20)DHVQFN20: plastic dual in-line compatible thermal enhanced very thin quad flat package; no leads;Fig. 11.Package outline SOT764-1 (DHVQFN20)12. Abbreviations13. Revision history14. Legal informationData sheet status[1]Please consult the most recently issued document before initiating orcompleting a design.[2]The term 'short data sheet' is explained in section "Definitions".[3]The product status of device(s) described in this document may havechanged since this document was published and may differ in case ofmultiple devices. The latest product status information is available onthe internet at https://.DefinitionsDraft — The document is a draft version only. The content is still under internal review and subject to formal approval, which may result in modifications or additions. Nexperia does not give any representations or warranties as to the accuracy or completeness of information included herein and shall have no liability for the consequences of use of such information. Short data sheet — A short data sheet is an extract from a full data sheet with the same product type number(s) and title. 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Nexperia makes no representation or warranty that such applications will be suitable for the specified use without further testing or modification.Customers are responsible for the design and operation of their applications and products using Nexperia products, and Nexperia accepts no liability for any assistance with applications or customer product design. It is customer’s sole responsibility to determine whether the Nexperia product is suitableand fit for the customer’s applications and products planned, as well asfor the planned application and use of customer’s third party customer(s). Customers should provide appropriate design and operating safeguards to minimize the risks associated with their applications and products. Nexperia does not accept any liability related to any default, damage, costs or problem which is based on any weakness or default in the customer’s applications or products, or the application or use by customer’s third party customer(s). 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Constant or repeated exposure to limiting values will permanently and irreversibly affect the quality and reliability of the device.Terms and conditions of commercial sale — Nexperia products aresold subject to the general terms and conditions of commercial sale, as published at /profile/terms, unless otherwise agreed in a valid written individual agreement. In case an individual agreement is concluded only the terms and conditions of the respective agreement shall apply. Nexperia hereby expressly objects to applying the customer’s general terms and conditions with regard to the purchase of Nexperia products by customer.No offer to sell or license — Nothing in this document may be interpreted or construed as an offer to sell products that is open for acceptance or the grant, conveyance or implication of any license under any copyrights, patents or other industrial or intellectual property rights.Export control — This document as well as the item(s) described herein may be subject to export control regulations. Export might require a prior authorization from competent authorities.Non-automotive qualified products — Unless this data sheet expressly states that this specific Nexperia product is automotive qualified, the product is not suitable for automotive use. It is neither qualified nor tested in accordance with automotive testing or application requirements. Nexperia accepts no liability for inclusion and/or use of non-automotive qualified products in automotive equipment or applications.In the event that customer uses the product for design-in and use in automotive applications to automotive specifications and standards, customer (a) shall use the product without Nexperia’s warranty of the product for such automotive applications, use and specifications, and (b) whenever customer uses the product for automotive applications beyond Nexperia’s specifications such use shall be solely at customer’s own risk, and (c) customer fully indemnifies Nexperia for any liability, damages or failed product claims resulting from customer design and use of the product for automotive applications beyond Nexperia’s standard warranty and Nexperia’s product specifications.Translations — A non-English (translated) version of a document is for reference only. The English version shall prevail in case of any discrepancy between the translated and English versions.TrademarksNotice: All referenced brands, product names, service names and trademarks are the property of their respective owners.Contents1. General description (1)2. Features and benefits (1)3. Ordering information (2)4. Functional diagram (2)5. Pinning information (3)5.1. Pinning (3)5.2. Pin description (3)6. Functional description (3)7. Limiting values (4)8. Recommended operating conditions (4)9. Static characteristics (5)10. Dynamic characteristics (7)10.1. Waveforms and test circuit (8)11. Package outline (10)12. Abbreviations (14)13. Revision history (14)14. Legal information (15)© Nexperia B.V. 2018. All rights reservedFor more information, please visit: Forsalesofficeaddresses,pleasesendanemailto:*************************** Date of release: 11 September 2018Mouser ElectronicsAuthorized DistributorClick to View Pricing, Inventory, Delivery & Lifecycle Information:N experia:74LVC245AD74LVCH245AD74LVCH245ADB74LVCH245APW74LVC245APW74LVC245ABQ,115 74LVC245AD,11274LVC245ADB,11274LVC245ADB,11874LVC245AD,11874LVC245APW,11274LVC245APW,11874LVCH245ABQ,11574LVCH245AD,11274LVCH245ADB,11274LVCH245ADB,118 74LVCH245AD,11874LVCH245APW,11274LVCH245APW,11874LVC245ABX,11574LVCH245ABX,115 74LVCH245APW/AUJ74LVC245APW/AUJ。
74HC245C(文件编号:S&CIC1504)八同相三态总线收发器一、概述这种八线收发器设计用于异步双向数据总线通信,这种控制功能的实现最大限度地减少了外部时间的要求。
该器件允许数据从A总线传输到B总线或从B总线传到A总线,这种数据传输的方向取决于DIR脚的电平。
输出使能脚(/OE)的输入能有效的将数据总线隔离。
74HC245C的工作温度范围为–40℃到85℃。
二、特点采用COMS工艺宽电压工作范围:3.0V~5.0V双向三态输出八线双向收发器采用的封装形式:SOP-20,TSSOP-20、QFN20(4X4)74HC245C(文件编号:S&CIC1504)八同相三态总线收发器五、绝对最大额定值74HC245C(文件编号:S&CIC1504)八同相三态总线收发器七、交流特性(VDD=5V Tamb=25℃)八、电气特性操作特性(TA=25℃)74HC245C(文件编号:九、参数测量信息3、波形之间的相位关系是被任意选择的,所有输入脉冲是由具有以下特点的信号发生器提供:PRR≤1MHz,Z O=50Ω,t r=6ns,t f=6ns.4、每一次输入数据的改变测量一次输出。
5、t PLZ和t PHZ与t dis是一样的。
6、t PZL和t PZH与t en是一样的。
7、t PLH和t PHL与t pd是一样的。
74HC245C(文件编号:S&CIC1504)八同相三态总线收发器十、封装信息TSSOP-20符号最小值典型值最大值A-- 1.10 1.15A10.02--0.08A20.95 1.00 1.05A30.380.430.48b0.170.220.25c0.100.150.20D 6.40 6.50 6.60E 6.30 6.40 6.50E1 4.30 4.40 4.50e0.65BSCL0.570.620.67L1 1.05BSCθ0°3°6°74HC245C(文件编号:S&CIC1504)八同相三态总线收发器。
MC74LVX245Octal Bus TransceiverWith 5 V−Tolerant InputsThe MC74LVX245 is an advanced high speed CMOS octal bus transceiver.It is intended for two−way asynchronous communication between data buses. The direction of data transmission is determined by the level of the T/R input. The output enable pin (OE) can be used to disable the device, so that the buses are effectively isolated.All inputs are equipped with protection circuits against static discharge.Features•High Speed: t PD = 4.7 ns (Typ) at V CC = 3.3 V•Low Power Dissipation: I CC = 4 m A (Max) at T A = 25°C •Power Down Protection Provided on Inputs •Balanced Propagation Delays •Low Noise: V OLP = 0.8 V (Max)•Pin and Function Compatible with Other Standard Logic Families •Latchup Performance Exceeds 300 mA•ESD Performance:Human Body Model > 2000 V;Machine Model > 200 V•These Devices are Pb−Free and are RoHS CompliantApplication Notes•Do Not Force a Signal on an I/O Pin when it is an Active Output,Damage May Occur•All Floating (High Impedance) Input or I/O Pins must be Fixed by Means of Pullup or Pulldown Resistors or Bus Terminator ICs •A Parasitic Diode is Formed between the Bus and V CC Terminals Therefore, the LVX245 cannot be Used to Interface 5.0 V to 3.0 VSystems DirectlySee detailed ordering and shipping information in the package dimensions section on page 5 of this data sheet.ORDERING INFORMATION120MARKING DIAGRAMSSOIC−20DW SUFFIX CASE 751DTSSOP−20DT SUFFIX CASE 948ELVX245= Specific Device Code A = Assembly Location WL, L = Wafer Lot Y= YearWW, W = Work WeekG or G= Pb−Free Package(Note: Microdot may be in either location)LVX 245ALYW G GSOIC−20TSSOP−20PIN ASSIGNMENT20−Lead (Top View)192018171615142134567V CC 1381291110OE B0B1B2B3B4B5B6B7T/R A0A1A2A3A4A5A6A7GNDB0OE 19T/R 1A0B1A1B2A2B3A3B4A4B5A5B6A6B7A7Figure 1. Logic DiagramTable 1. PIN NAMESPins FunctionOE T/R A0−A7Bo−B7Output Enable Input Transmit/Receive InputSide A 3−State Inputs or 3−State Outputs Side B 3−State Inputs or 3−State OutputsINPUTS OPERATING MODE Non−Inverting OE T/R L L B Data to A Bus L H A Data to B Bus HXZH = High Voltage Level; L = Low Voltage Level; Z = High Impedance State;X = High or Low Voltage Level and Transitions are Acceptable; For I CC reasons, Do Not Float InputsMAXIMUM RATINGSSymbol Parameter Value Unit V CC DC Supply Voltage–0.5 to +7.0V V in DC Input Voltage (T/R, OE)–0.5 to +7.0V V I/O DC Output Voltage–0.5 to V CC +0.5VI IK Input Diode Current−20mAI OK Output Diode Current±20mAI out DC Output Current, per Pin±25mAI CC DC Supply Current, V CC and GND Pins±75mAP D Power Dissipation180mW T stg Storage Temperature–65 to +150°C Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected.RECOMMENDED OPERATING CONDITIONSSymbol Parameter Min Max Unit V CC DC Supply Voltage 2.0 3.6V V in DC Input Voltage (T/R, OE)0 5.5V V I/O DC Output Voltage0V CC V T A Operating Temperature, All Package Types−40+85°CD t/D V Input Rise and Fall Time0100ns/V Functional operation above the stresses listed in the Recommended Operating Ranges is not implied. Extended exposure to stresses beyond the Recommended Operating Ranges limits may affect device reliability.DC ELECTRICAL CHARACTERISTICSSymbol Parameter Test Conditions V CCVT A = 25°C T A = −40 to 85°CUnit Min Typ Max Min MaxV IH High−Level Input Voltage 2.03.03.61.52.02.41.52.02.4VV IL Low−Level Input Voltage 2.03.03.60.50.80.80.50.80.8VV OH High−Level Output Voltage(V in = V IH or V IL)I OH = −50 m AI OH = −50 m AI OH = −4 mA2.03.03.01.92.92.582.03.01.92.92.48VV OL Low−Level Output Voltage(V in = V IH or V IL)I OL = 50 m AI OL = 50 m AI OL = 4 mA2.03.03.00.00.00.10.10.360.10.10.44VI in Input Leakage Current V in = 5.5 V or GND(T/R, OE)3.6±0.1±1.0m AI OZ Maximum 3−State Leakage Current V in = V IL or V IHV out = V CC or GND 3.6±0.25±2.5m AI CC Quiescent Supply Current V in = V CC or GND 3.6 4.040.0m A Product parametric performance is indicated in the Electrical Characteristics for the listed test conditions, unless otherwise noted. Product performance may not be indicated by the Electrical Characteristics if operated under different conditions.AC ELECTRICAL CHARACTERISTICS (Input t r = t f= 3.0 ns)Symbol Parameter Test ConditionsT A = 25°C T A = −40 to 85°CUnit Min Typ Max Min Maxt PLH, t PHL Propagation DelayInput to OutputV CC = 2.7 V C L = 15 pFC L = 50 pF6.18.610.714.21.01.013.517.0nsV CC = 3.3 ± 0.3 V C L = 15 pFC L = 50 pF4.77.26.610.11.01.08.011.5t PZL, t PZH Output Enable Time toHigh and Low LevelV CC = 2.7 V C L = 15 pFR L = 1 k W C L = 50 pF9.011.516.920.41.01.020.524.0nsV CC = 3.3 ± 0.3 V C L = 15 pFR L = 1 k W C L = 50 pF7.19.611.014.51.01.013.016.5t PLZ, t PHZ Output Disable Time FromHigh and Low LevelV CC = 2.7 V C L = 50 pFR L = 1 k W11.518.0 1.021.0nsV CC = 3.3 ± 0.3 V C L = 50 pFR L = 1 k W9.612.8 1.014.5t OSHL t OSLH Output−to−Output Skew(Note 1)V CC = 2.7 V C L = 50 pFV CC = 3.3 ±0.3 V C L = 50 pF1.51.51.51.5ns1.Skew is defined as the absolute value of the difference between the actual propagation delay for any two separate outputs of the same device.The specification applies to any outputs switching in the same direction, either HIGH−to−LOW (t OSHL) or LOW−to−HIGH (t OSLH); parameter guaranteed by design.CAPACITIVE CHARACTERISTICSSymbol ParameterT A = 25°C T A = −40 to 85°CUnit Min Typ Max Min MaxC in Input Capacitance (T/R, OE)41010pFC I/O Maximum 3−State I/O Capacitance8pFC PD Power Dissipation Capacitance (Note 2)21pF2.C PD is defined as the value of the internal equivalent capacitance which is calculated from the operating current consumption without load.Average operating current can be obtained by the equation: I CC(OPR) = C PD V CC f in + I CC/8 (per bit). C PD is used to determine the no−load dynamic power consumption; P D = C PD V CC2 f in + I CC V CC.NOISE CHARACTERISTICS (Input t r = t f = 3.0ns, C L = 50pF, V CC = 3.3V, Measured in SOIC Package)Symbol CharacteristicT A = 25°CUnit Typ MaxV OLP Quiet Output Maximum Dynamic V OL0.50.8V V OLV Quiet Output Minimum Dynamic V OL−0.5−0.8V V IHD Minimum High Level Dynamic Input Voltage 2.0V V ILD Maximum Low Level Dynamic Input Voltage0.8VFigure 2. Figure 3.V CCGNDSWITCHING WAVEFORMSOEA or BA or BV CCGND HIGHIMPEDANCE V OL +0.3V V OH -0.3V HIGHIMPEDANCEV CC GNDT/R*Includes all probe and jig capacitance C L *TEST POINT *Includes all probe and jig capacitanceTEST POINT CONNECT TO V CC WHEN TESTING t PLZ AND t PZL .CONNECT TO GND WHEN TESTING t PHZ AND t PZH .TEST CIRCUITSFigure 4. Propagation Delay Test Circuit Figure 5. 3−State Test CircuitORDERING INFORMATIONDevicePackage Shipping †MC74LVX245DWR2G SOIC−20(Pb−Free)1000 / Tape & Reel MC74LVX245DTR2GTSSOP−20(Pb−Free)2500 / Tape & Reel†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D.CASE 948E−02ISSUE CDIM A MIN MAX MIN MAX INCHES 6.600.260MILLIMETERS B 4.30 4.500.1690.177C 1.200.047D 0.050.150.0020.006F 0.500.750.0200.030G 0.65 BSC 0.026 BSC H 0.270.370.0110.015J 0.090.200.0040.008J10.090.160.0040.006K 0.190.300.0070.012K10.190.250.0070.010L 6.40 BSC 0.252 BSCM0 8 0 8 ____NOTES:1.DIMENSIONING AND TOLERANCING PER ANSI Y14.5M, 1982.2.CONTROLLING DIMENSION:MILLIMETER.3.DIMENSION A DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH OR GATE BURRS SHALL NOT EXCEED 0.15 (0.006) PER SIDE.4.DIMENSION B DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION.INTERLEAD FLASH OR PROTRUSIONSHALL NOT EXCEED 0.25 (0.010) PER SIDE.5.DIMENSION K DOES NOT INCLUDE DAMBAR PROTRUSION. ALLOWABLE DAMBAR PROTRUSION SHALL BE 0.08(0.003) TOTAL IN EXCESS OF THE K DIMENSION AT MAXIMUM MATERIAL CONDITION.6.TERMINAL NUMBERS ARE SHOWN FOR REFERENCE ONLY .7.DIMENSION A AND B ARE TO BE DETERMINED AT DATUM PLANE −W−.DETAIL E6.400.252------16X0.360.65PITCHSOLDERING FOOTPRINT**For additional information on our Pb−Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D.CASE 751D−05ISSUE GM0.25SA SBTDIM MIN MAXMILLIMETERSA 2.35 2.65A10.100.25B0.350.49C0.230.32D12.6512.95E7.407.60e 1.27 BSCH10.0510.55h0.250.75L0.500.90q0 7NOTES:1.DIMENSIONS ARE IN MILLIMETERS.2.INTERPRET DIMENSIONS AND TOLERANCESPER ASME Y14.5M, 1994.3.DIMENSIONS D AND E DO NOT INCLUDE MOLDPROTRUSION.4.MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.5.DIMENSION B DOES NOT INCLUDE DAMBARPROTRUSION. ALLOWABLE PROTRUSIONSHALL BE 0.13 TOTAL IN EXCESS OF BDIMENSION AT MAXIMUM MATERIALCONDITION.__ON Semiconductor and the are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries.SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at /site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. 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SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.PUBLICATION ORDERING INFORMATIONMouser ElectronicsAuthorized DistributorClick to View Pricing, Inventory, Delivery & Lifecycle Information:O N Semiconductor:MC74LVX245MELG MC74LVX245MG MC74LVX245DTR2MC74LVX245DTR2G MC74LVX245DWR2 MC74LVX245DWR2G。
八路总线收发器具有热插入和总线保持功能补充
Diodes公司逻辑产品组合
Diodes 公司推出能够在数据总线之间实现异步通信的74LVT245BB 八路收发器,其控制引脚确定数据流方向,同时禁用三态输出,允许总路线完全隔离。
数据总线以往主要用于计算机应用,现在电视机、机顶盒、基站和多种其它数据通信设备中广泛应用,为各种收发器电路提供了广阔的市场。
74LVT245BB器件为数据总线之间的正常异步通信提供了部分掉电功能,从而禁用输出并且在设备掉电时防止损坏电流回流。
这款器件还通过在上电期间保持三态输出来耐受热插入。
施密特触发输入还包括总线保持功能,因而未使用的输入无需电阻器。
结合优于500mA的闭锁免疫能力,这些收发器可推动实现广泛的设计,能够在计算机服务器和蜂窝电话基站等应用中进行热插拨而无需关闭设备。
74LVT245BB器件指定在2.7V至3.6V供电电压范围运作,可以在3.3V或5V驱动输入,允许混合逻辑电压应用。
其输出可以吸收64mA或提供32mA电流,并且在强制达到5.5V时具有《125μA的泄漏电流。
74LVT245BB器件的传播时间为2.7ns (典型),具有适用于大型总线架构的驱动能力,以及掉电以避免载入数据总线的功能,在功率性能比、可靠性和成本方面带来优势。
74LVXC3245MTCX原理1.概述本文档将介绍74LV XC3245M TC X芯片的原理、功能及使用方法。
该芯片是一种高集成度、高速驱动能力的双向总线转换器。
它具有诸多特点和应用场景,本文将详细讲解。
2. 74LVXC3245MTC X芯片的特点-双向总线转换器,能够实现逻辑电平的双向转换-低功耗设计,适用于电池供电系统-高速传输,最大传输速率可达100MH z-支持5V和3.3V之间的电平转换3.功能描述74LV XC3245MT CX芯片具有以下主要功能:3.1电平转换该芯片可以实现5V和3.3V之间的双向电平转换。
通过引脚的设置,可以将5V逻辑电平转换为3.3V逻辑电平,或者将3.3V逻辑电平转换为5V逻辑电平。
3.2双向传输该芯片支持双向数据传输,可以在两个总线之间进行数据的双向传输。
它能够实现将数据从一侧总线传输到另一侧总线,同时保持两侧总线的输入输出状态。
3.3高速传输74LV XC3245MT CX芯片具有高速传输的能力,最大传输速率可达100M Hz。
这使得它适用于高速数据传输的场景,如计算机总线、存储器接口等。
4.使用方法使用74LV XC3245MTC X芯片进行电平转换和双向传输的方法如下:1.设置引脚电平:根据需求,将DI R引脚设置为高电平或低电平,以确定数据传输的方向。
2.连接总线:将要进行转换的两个总线分别连接到A端和B端。
3.数据传输:通过控制DI R引脚的电平,实现双向数据的传输。
使用74LV XC3245MTC X芯片时需要注意以下事项:-确保供电电压符合芯片的规格要求,以避免损坏芯片或降低性能。
-使用正确的引脚连接方式,确保总线连接正确无误。
-在高速传输时,要保持信号线的稳定性,减少信号干扰。
5.应用场景74LV XC3245MT CX芯片广泛应用于以下场景:1.计算机总线:用于连接不同电平的总线,实现数据的双向传输和电平转换。
2.存储器接口:用于连接处理器和存储器,实现高速数据的传输。
74hc245 的作用是什么74hc245 应用原理是什么
大家都知道,74hc245CMOS 高速收发器,那幺它有什幺作用你知道吗,它在电路中的应用原理呢?本文讲解的是74hc245 的作用是什幺,以及
74hc245 应用原理是什幺。
74hc245
74hc245 是一种兼容TTL 器件引脚的高速CMOS 总线收发器(bus transceiver),典型的CMOS 型三态缓冲门电路,八路信号收发器。
由于单片机或CPU 的数据/地址/控制总线端口都有一定的负载能力,如果负载超过其负载能力,一般应加驱动器。
主要应用于大屏显示,以及其它的消费类电子产品中增加驱动。
特征
输出驱动能力:15 个LTSTL 负载
输出直接与CMOS、NMOS 和TTL 接口。
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基于STM32的报警显示系统设计张文新【摘要】Introduces a kind of Warning and Display System, in this system, the chip that STM32F103VE is the operation core, FPGA is the control component of timer and logic, and AD9985A is the analog to digital converter. The hardware design of this systemˊs is simple, and relia-bility is high. It can be flexibly applied to all kinds of industrial data acquisition system which requires the human-computer interaction using environment, and has a wide application prospect.%介绍一种以STM32F103VE芯片为主控制器,以FPGA芯片为时序逻辑控制器,以AD9985A芯片为模数转换器的实时报警显示系统。
该系统硬件架构简单,可靠性高,可灵活应用于各种需要人机交互使用环境的工业级数据采集系统中,应用前景广泛。
【期刊名称】《现代计算机(专业版)》【年(卷),期】2016(000)020【总页数】6页(P85-90)【关键词】报警显示系统;STM32F103VE;AD9985A;人机交互【作者】张文新【作者单位】广州海格通信集团股份有限公司,广州 510663【正文语种】中文介绍一种以STM32F103VE芯片为主控制器,以FPGA芯片为时序逻辑控制器,以AD9985A芯片为模数转换器的实时报警显示系统。
该系统硬件架构简单,可靠性高,可灵活应用于各种需要人机交互使用环境的工业级数据采集系统中,应用前景广泛。
8线总线收发器SN74LVCC3245的原理及应用
在新一代电子产品设计与应用中,低功耗和高速度已经成为数字电路设计的发展趋势。
但是众所再知,芯片的功耗与频率成正比关系,这两个看似不可调和的矛盾,最终导致了各种低压数字器件的出现。
如TI公司的TMS320F2812就采用了核心1.8V和外围电路由3.3V供电的架构,但这也同时带来了新的问题,就是大多数外围数字芯片仍为TTL或CMOS逻辑电平,当把微处理器I/O电压移植到较低的节点,而外设仍留在电压较高的节点时,经常会出现微处理器与外设I/O之间电压不匹配的现象。
针对上述问题,德州仪器(TI)推出了AVC及LVC等多款新型双电源电平转换收发器,从而为运行于不同电压节点上的接口设备提供了理想的选择。
这些转换产品能够在1.5V、1.8V、2.5V、3.3V与5V电压节点之间进行灵活的双向电平转换,因此非常适用于便携式消费类电子产品、网络、数据通信及计算应用领域。
TI的新型双电源电平转换器件能够在保持信号完整性及速度不变的情况下,在接口电压完全不同的两个设备之间进行通信。
此外,该系列器件还提供全面的可配置性,如果采用AVC技术,则每条轨可从1.4V配置为3.6V,而采用LVC技术则可从1.65V配置为5.5V。
本文介绍带有三态输出且输出电压可调的8线总线双向电平转换器SN74LVCC3245的原理及应用。
1 SN74LVCC3245简介
SN74LVCC3245是8位正逻辑总线收发器,它有两个独立供电电源轨。
其中B口被用来跟踪Vccb电压,可以接收的电压范围为3V到5.5V,与此相对应的A口则用来跟踪VCCA电压,可以接收的电压范围为2.5V到3.6V。
这种结构允许数字逻辑从一个供电电压为3.3V的系统环境转换到一个供电电压为5.5V的系统环境,反之亦然。
SN74LVCC3245可以应用于数字总线间的异步通讯,完全数据从A总线到B总线或B总线到A 总线的数字传递,传递方向取决于方向控制引脚DIR上的逻辑电平。
输出允许引脚OE可以用来禁用器件,这样可对总线进行有效隔离。
这些控制电路(DIR,OE)是由VCCA供电的。
图1示出SN74LVCC3245的引脚排列。
SN74LVCC3245双向电平转换器具有如下主要特点:
·双向电压转换;
·A口输出电压范围为2.3V~3.6V;B口输出电压范围为3V~5.5V;
·控制输入信号VIH/VIL逻辑电平参数VCCA的电压
2 真值表和内部逻辑
表1是SN74LVCC3245的逻辑真值表,当OE和DIR均为低电平时,数据由B口传输到A口;当OE为低电平而DIR为高电平时,数据由A口传输到B口;如果OE为高电平,则器件将与外部总线隔离。
3 SN74LVCC3245在DSP中的应用
DSP以其强大的信号处理能力见长,但控制能力却明显不足。
因此,当设计控制口线较多的系统时,可采用双处理器的方法(即采用DSP加控制器力相对较强的普通52单片机)来构成整个系统,这样,DSP作为下位机发挥其运行能力强的优势来进行信号处理,并通过串口与上位机(单片机)通讯,接收其控制指令和设置参数,并将处理好的数据传输到52单片机,而单片机完成数据显示、打印等控制功能。
这样,在该系统中就会存在电平不匹配的问题。
如系统使用的DSP是TI公司的TMS320F2812,那么,其I/O电源是3.3V,但普通52单片机的数字逻辑电平为5V的CMOS电平,这就需要对两者通讯所用的串口信号线进行电平转换。
此外,SPI(serial peripheral interface)总线串口是由Motorola公司提出的一种同步串行外设接口,该接口通常也需要完成TxD和RxD这两根信号线的电平转换。
VHC245内部结构。