Gate current variation

AN2986

14/18

Doc ID 15727 Rev 1

precision of power supply has been taken into account and is appropriate according to our

results. An SMPS + linear voltage regulator have to be used in order to achieve this

accuracy (example VIPER16 + LM337).

MCUs with negative 5 V power supply have some advantages concerning power supply.

Precision of ±10% is enough and can be achieved using capacitive power supply or SMPS

without additional regulation (example VIPER16, assuming a minimum output current 2

mA).

It should be noted that ACS devices are the better candidates for operation with a 3.3 V

ripple, this helps to decrease the current consumption (maximum average gate current is

19.4 mA with 3.3 V compared to 22.8 mA with 5 V).

Placing the pins in parallel is necessary to control the 10 mA gate current AC switches with

a 3.3 V supply as the maximum gate current is 60 to 80% above the maximum allowed sunk

current for the I/O MCU pin (for example: STM8S103xx).

For a 5 V supply, the maximum calculated gate current (around 23 mA) is very close to the

maximum allowed I/O pin current. So according to application conditions (min. ambient