PCAL 6534 Power sequence

[sohee]

Is there any power that needs to be turn on first, VDD(P) or VDD(I2C_BUS)?

Does it need a power sequence for PCAL6534?

[TomasVaverka]

Hi,

VDD(P) should be powered first or at least not later than VDD(I2C_BUS). This ensures the internal circuits and registers are properly initialized before communication begins.

BRs, Tomas

[sohee]

Is there exact power sequence that contains timing?

Actually, VDD_I2C is powered first than VDD_P in design.

[TomasVaverka]

Hi,

There is no exact timing sequence specified. If VDD_I2C is powered first in your design, ensure that VDD_P ramps up promptly and reaches the POR threshold before any I²C communication is attempted. Note that the POR reset delay time is approximately 1 µs after VDD_P crosses the threshold. So to ensure reliable operation, allow a short delay (e.g. a few microseconds) after VDD_P is stable before initiating I²C transactions.

BRs, Tomas