SLLSFR9A April   2024  – April 2024 THVD4411

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  ESD Ratings [IEC]
    4. 5.4  Recommended Operating Conditions
    5. 5.5  Thermal Information
    6. 5.6  Power Dissipation
    7. 5.7  Electrical Characteristics
    8. 5.8  Switching Characteristics_RS-485_500kbps
    9. 5.9  Switching Characteristics_RS-485_20Mbps
    10. 5.10 Switching Characteristics, Driver_RS232
    11. 5.11 Switching Characteristics, Receiver_RS232
    12. 5.12 Switching Characteristics_MODE switching
    13. 5.13 Switching Characteristics_RS-485_Termination resistor
    14. 5.14 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Integrated IEC ESD and EFT Protection
      2. 7.3.2 Protection Features
      3. 7.3.3 Receiver Fail-Safe Operation
      4. 7.3.4 Low-Power Shutdown Mode
      5. 7.3.5 On-chip Switchable Termination resistor
      6. 7.3.6 Operational Data Rate
      7. 7.3.7 Integrated Charge Pump for RS-232
    4. 7.4 Device Functional Modes
      1. 7.4.1 RS-485 Functionality
      2. 7.4.2 RS-232 Functionality
      3. 7.4.3 Mode Control
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
        1. 8.2.1.1 Data Rate and Bus Length
        2. 8.2.1.2 Stub Length
        3. 8.2.1.3 Bus Loading
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.4.2 RS-232 Functionality

In RS-232 mode, only way to disable driver is to go in shutdown mode by pulling SHDN pin low. A logic high at input for driver L2 causes driver output R3 to be driven low towards negative charge pump output V-. A logic low at input for driver L2 causes driver output R3 to be driven high towards positive charge pump output V+. If logic input is left floating due to the pull-up resistors on driver logic input, the driver output is driven low towards V-.

Table 7-6 Driver Function Table
INPUT ENABLE OUTPUTS FUNCTION
L2 SHDN R3
H H Low (driven towards V-) Normal operation with inverting logic
L H H (Driven towards V+) Normal operation with inverting logic
X L High impedance TX and RX are disabled in shutdown mode
Open H Low (driven towards V-) Since pull-up on logic input pin, output driven low by default

Table 7-6 is valid irrespective of the state of SLR pin.

For RS-232 receiver, if receiver bus input is above rising threshold VIT+, then received logic output goes low. Also, if receiver bus input is below falling threshold VIT-, received logic output goes high.

Table 7-7 Receiver Function Table
RS-232 BUS INPUT LOGIC OUTPUT FUNCTION
VIRx (voltage on R2) L1
VIT+ < VIRx L Normal operation with inverting logic
VIT- < VIRx < VIT+ ? Indeterminate bus state
VIRx < VIT- H Normal operation with inverting logic
X High impedance for SHDN = GND Receiver disabled in shutdown mode
Open-circuit bus H Fail-safe high output

Table 7-7 is valid irrespective of the state of SLR pin.