ZHCSIG4A July 2018 – June 2019 DLPC3434
The DLPC3434 provides fail-safe I/O on all host interface signals (signals powered by VCC_INTF). This allows these inputs to be driven high even when no I/O power is applied. Under this condition, the DLPC3434 will 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 would not be affected by powering off VCC_INTF to the DLPC3434. TI recommends weak pullups or pulldowns 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 DLPC3434.