SDAA460 July   2026 ISOUSB211

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Power Pins and Internal Rails
  6. 3Available Supply Options
    1. 3.1 Generating the 3.3V Rail (V3P3Vx)
    2. 3.2 Generating the 1.8V Rail (V1P8Vx)
    3. 3.3 Summary of the Four Building Blocks
  7. 4Typical Example Power Configurations
    1. 4.1 Power Configuration for an Isolated Host or Hub (Mixed Internal and External)
    2. 4.2 Power Configuration for Isolating a Self-Powered Peripheral
    3. 4.3 Power Configuration for Isolating a Bus-Powered Peripheral
  8. 5Thermal Considerations When Selecting a Supply Configuration
    1. 5.1 Operation Without External 1.8V Supply
    2. 5.2 Operation With External 1.8V Supply
  9. 6References
  10. 7Revision History

5.2 Operation With External 1.8V Supply

The device can also be supplied with external 1.8V supply on both the sides. In this configuration, the internal 1.8V LDOs on both the sides do not consume any power from the VCC pins which minimizes the internal power dissipation of the device. Figure 5-3 shows this example configuration.

This configuration offers the lowest power dissipation and the highest ambient temperature operation up to 128°C. Therefore, supply the device externally whenever a local external 1.8V rail is available to keep the device cooler.

For detailed thermal calculation of operation with the external 1.8V supply, see the Example Configuration 2 section in the ISOUSB211: 480Mbps High-Speed Reinforced USB Isolator datasheet.

Using ISOUSB211 With External 1.8V Supply On Both Sides Figure 5-3 Using ISOUSB211 With External 1.8V Supply On Both Sides