JAJSF42B April 2018 – June 2019 DLPC3478
The DLPC3478 device provides fail-safe I/O on all host interface signals (signals powered by VCC_INTF). This protection allows these inputs to be driven high even when no I/O power is applied. Under this condition, the device does not load the input signal nor draw excessive current that could degrade ASIC reliability. For example, the I2C bus from the host to other components is not affected by powering off VCC_INTF to the DLPC3478 device. TI recommends the application include weak pullup or pulldown components on signals feeding back to the host to avoid floating inputs.
If the I/O supply (VCC_INTF) is powered off, but the core supply (VDD) is powered on, then the corresponding input buffer may experience added leakage current, but this does not damage the DLPC3478.