Capacity at CVDD pin of L6362A

Central SUPPORT · ‎2019-07-29

The other info I struggle is on page 12 in the datasheet:

CVDD higher than recommend values is allowed but external protection nets on VDD could be necessary for high VCC slew rate (>15 V/μs).

In fact, we would like to use a bigger blocking capacitor like 1 uF on the CVDD. Current is limited internally to 20mA anyway, right? So why not using 1 uF then?

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Central SUPPORT · ‎2019-07-29

You're right there is a current limitation integrated which can limit the current at a certain level between 10-20mA (see Table 13 of the datasheet). The operating current range of integrated regulator is thus in range up to 10mA. But we recommend to use CVDD in range of 68nF as we identified some sensitivity of the integrated regulator to inrush current peaks that can occur eg. during hot-plug transients (high dV/dt on the power supply).

In case you need to use a bigger capacitor (e.g. 1uF) then we recommend to limit startup dI/dt transient of the regulator by a simple circuit with an RC network + bipolar transistor between the VDD pin and CVDD capacitor.

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Central SUPPORT · ‎2019-07-29

You're right there is a current limitation integrated which can limit the current at a certain level between 10-20mA (see Table 13 of the datasheet). The operating current range of integrated regulator is thus in range up to 10mA. But we recommend to use CVDD in range of 68nF as we identified some sensitivity of the integrated regulator to inrush current peaks that can occur eg. during hot-plug transients (high dV/dt on the power supply).

In case you need to use a bigger capacitor (e.g. 1uF) then we recommend to limit startup dI/dt transient of the regulator by a simple circuit with an RC network + bipolar transistor between the VDD pin and CVDD capacitor.