SLLA637 May   2024 THVD4431

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Key Feature Highlights of THVD4431 Over XR34350 and SP339E/B
    1. 2.1 Regulated Output Voltage for RS-232
    2. 2.2 Full Path Diagnostic Loopback
    3. 2.3 Operating Ambient Temperature Range
    4. 2.4 Integrated Switchable Termination Resistor on Both Driver (R1/R2) and Receiver (R3/R4) Bus Pins
    5. 2.5 1.65V to 5.5V Supply for Logic Data and Control Signals
  6. 3Potential Design Changes
    1. 3.1 Pin 9 (VIO)
    2. 3.2 Pin 13 (MODE2)
    3. 3.3 Pin 17 (TERM_TX) and Pin 18 (TERM_RX)
    4. 3.4 Pin 19 (SHDN)
    5. 3.5 Pin 36 (NC)
  7. 4Pinout Mapping
  8. 5Summary
  9. 6References

2.5 1.65V to 5.5V Supply for Logic Data and Control Signals

THVD4431 provides a separate logic supply pin (pin 9), different than the main bus supply VCC. VIO allows users to interface THVD4431 with microcontrollers (MCU) operating at low voltage supply level such as 1.8V or 2.5V. Even for the applications which want to run RS-232 or RS-485 bus side circuitry at 5V, a 3.3V MCU interface is still possible with THVD4431. This application use case is not enabled by Maxlinear XR34350 or SP339E/B.

To enable this feature, connect the desired logic supply voltage to pin 9 and add a 100nF bypass capacitor close to pin 9, as shown in Figure 2-6. If this feature is not needed, simply connect pin 9 to the same voltage rail as other VCC pins and keep the same bypass capacitor (100nF). Voltage within recommended operating condition is needed on pin 9VIO for THVD4431 to function properly, this pin cannot be left floating.

THVD4431 Application Schematic Figure 2-6 THVD4431 Application Schematic