SLLS808A JULY   2007  – November 2016 TRS202

UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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
    6. 6.6  Electrical Characteristics: Driver
    7. 6.7  Electrical Characteristics: Receiver
    8. 6.8  Switching Characteristics: Driver
    9. 6.9  Switching Characteristics: Receiver
    10. 6.10 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Power
      2. 8.3.2 RS-232 Driver
      3. 8.3.3 RS-232 Receiver
    4. 8.4 Device Functional Modes
      1. 8.4.1 VCC Powered by 5 V
      2. 8.4.2 VCC Unpowered
      3. 8.4.3 Truth Tables
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Capacitor Selection
      2. 9.1.2 Electrostatic Discharge (ESD) Protection
      3. 9.1.3 ESD Test Conditions
      4. 9.1.4 Human-Body Model (HBM)
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Capacitor Selection
      3. 9.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

8 Detailed Description

8.1 Overview

The TRS202 device is a dual driver and receiver that includes a capacitive voltage generator using four capacitors to supply TIA/EIA-232-F voltage levels from a single 5-V supply. Each receiver converts TIA/EIA-232-F inputs to 5-V TTL/CMOS levels. These receivers have shorted and open fail safe. The receiver can accept up to ±30-V inputs and decode inputs as low as ±3 V. Each driver converts TTL/CMOS input levels into TIA/EIA-232-F levels. Outputs are protected against shorts to ground.

8.2 Functional Block Diagram

TRS202 max202_mini2.gif

8.3 Feature Description

8.3.1 Power

The power block increases and inverts the 5-V supply for the RS-232 driver using a charge pump that requires four 0.1-µF external capacitors.

8.3.2 RS-232 Driver

Two drivers interface standard logic levels to RS-232 levels. The driver inputs do not have internal pullup resistors. Do not float the driver inputs.

8.3.3 RS-232 Receiver

Two Schmitt trigger receivers interface RS-232 levels to standard logic levels. Each receiver has an internal 5-kΩ load to ground. An open input results in a high output on ROUT.

8.4 Device Functional Modes

8.4.1 VCC Powered by 5 V

The device is in normal operation when powered by 5 V.

8.4.2 VCC Unpowered

When TRS202 is unpowered, it can be safely connected to an active remote RS-232 device.

8.4.3 Truth Tables

Table 1 and Table 2 list the function for each driver and receiver (respectively). Figure 9 shows the logic diagram.

Table 1. Function Table for Each Driver(1)

INPUT
DIN		 OUTPUT
DOUT
L H
H L
(1) H = High level, L = Low level

Table 2. Function Table for Each Receiver(1)

INPUT
RIN		 OUTPUT
ROUT
L H
H L
Open H
(1) H = High level, L = Low level,
Open = Input disconnected or connected driver off
TRS202 ld_lls576.gif Figure 9. Logic Diagram (Positive Logic)