ZHCS321I June   2009  – January 2015 ISO1050

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
  4. 修订历史记录
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics: Supply Current
    6. 6.6  Electrical Characteristics: Driver
    7. 6.7  Electrical Characteristics: Receiver
    8. 6.8  Switching Characteristics: Device
    9. 6.9  Switching Characteristics: Driver
    10. 6.10 Switching Characteristics: Receiver
    11. 6.11 Typical Characteristics
  7. Parameter Measurement Information
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 CAN Bus States
      2. 8.3.2 Digital Inputs and Outputs
      3. 8.3.3 Protection Features
        1. 8.3.3.1 TXD Dominant Time-Out (DTO)
        2. 8.3.3.2 Thermal Shutdown
        3. 8.3.3.3 Undervoltage Lockout and Fail-Safe
        4. 8.3.3.4 Floating Pins
        5. 8.3.3.5 CAN Bus Short-Circuit Current Limiting
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Bus Loading, Length and Number of Nodes
        2. 9.2.2.2 CAN Termination
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 PCB Material
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 文档支持
      1. 12.1.1 相关文档
    2. 12.2 商标
    3. 12.3 静电放电警告
    4. 12.4 术语表
  13. 13机械封装和可订购信息

封装选项

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • DUB|8
  • DW|16
散热焊盘机械数据 (封装 | 引脚)
订购信息

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

ISO1050 can be used with other components from TI such as a microcontroller, a transformer driver, and a linear voltage regulator to form a fully isolated CAN interface.

9.2 Typical Application

ISO1050 application_circuit_lls983.gifFigure 27. Application Circuit

9.2.1 Design Requirements

Unlike optocoupler-based solution, which needs several external components to improve performance, provide bias, or limit current, ISO1050 only needs two external bypass capacitors to operate.

9.2.2 Detailed Design Procedure

9.2.2.1 Bus Loading, Length and Number of Nodes

The ISO11898 Standard specifies a maximum bus length of 40 m and maximum stub length of 0.3 m with a maximum of 30 nodes. However, with careful design, users can have longer cables, longer stub lengths, and many more nodes to a bus. A high number of nodes requires a transceiver with high input impedance such as the ISO1050.

Many CAN organizations and standards have scaled the use of CAN for applications outside the original ISO11898 standard. They have made system level trade offs for data rate, cable length, and parasitic loading of the bus. Examples of some of these specifications are ARINC825, CANopen, CAN Kingdom, DeviceNet and NMEA200.

A CAN network design is a series of tradeoffs, but these devices operate over wide –12-V to 12-V common-mode range. In ISO11898-2 the driver differential output is specified with a 60-Ω load (the two 120-Ω termination resistors in parallel) and the differential output must be greater than 1.5 V. The ISO1050 is specified to meet the 1.5-V requirement with a 60-Ω load, and additionally specified with a differential output of 1.4 V with a 45-Ω load. The differential input resistance of the ISO1050 is a minimum of 30 kΩ. If 167 ISO1050 transceivers are in parallel on a bus, this is equivalent to a 180-Ω differential load. That transceiver load of 180 Ω in parallel with the 60 Ω gives a total 45 Ω. Therefore, the ISO1050 theoretically supports over 167 transceivers on a single bus segment with margin to the 1.2-V minimum differential input at each node. However for CAN network design margin must be given for signal loss across the system and cabling, parasitic loadings, network imbalances, ground offsets and signal integrity thus a practical maximum number of nodes is typically much lower. Bus length may also be extended beyond the original ISO11898 standard of 40 m by careful system design and data rate tradeoffs. For example, CAN open network design guidelines allow the network to be up to 1km with changes in the termination resistance, cabling, less than 64 nodes and significantly lowered data rate.

This flexibility in CAN network design is one of the key strengths of the various extensions and additional standards that have been built on the original ISO11898 CAN standard. In using this flexibility comes the responsibility of good network design.

9.2.2.2 CAN Termination

The ISO11898 standard specifies the interconnect to be a single twisted pair cable (shielded or unshielded) with 120-Ω characteristic impedance (ZO). Resistors equal to the characteristic impedance of the line should be used to terminate both ends of the cable to prevent signal reflections. Unterminated drop-lines (stubs) connecting nodes to the bus should be kept as short as possible to minimize signal reflections. The termination may be in a node, but if nodes may be removed from the bus, the termination must be carefully placed so that it is not removed from the bus.

ISO1050 typ_CAN_bus_llsea2.gifFigure 28. Typical CAN Bus

Termination may be a single 120-Ω resistor at the end of the bus, either on the cable or in a terminating node. If filtering and stabilization of the common mode voltage of the bus is desired, then split termination may be used. (See Figure 29). Split termination improves the electromagnetic emissions behavior of the network by eliminating fluctuations in the bus common-mode voltages at the start and end of message transmissions.

ISO1050 CAN_bus_term_llsea2.gifFigure 29. CAN Bus Termination Concepts

9.2.3 Application Curve

ISO1050 g001_lls984.gifFigure 30. Life Expectancy vs Working Voltage (ISO1050DUB)