In order for the pre-charge circuitry to dampen the effect of hot-swap insertion of the TCA4307 into an active I²C bus, V_CC must be applied before the SCL and SDA pins make contact to the main I²C bus. This is essential when the TCA4307 is placed on the add-on card circuit board, as in Section 8.2.4. Although the pre-charge circuitry exists on both the -IN and -OUT side, the example in Section 8.2.4 shows SCLIN and SDAIN connecting to the main bus. The supply voltage to VCC can be applied early by ensuring that the VCC and GND pin contacts are physically longer than the contacts for the SCLIN and SDAIN pins. If a voltage supervisor is used to control the voltage supply on the add-on card, additional delay exists before the 1 V pre-charge voltage is present on the SCL and SDA pins.