QDo I need to supply the VDDA or VDDB pin? The datasheet of the similar ADuM1230
shows an application example (page 9) with floating (not connected) VDDA and
VDDB pins. Does this figure(fig.14) also apply to ADUM1233?
AYes, you do need to supply the VDDA and VDDB pin, usually with an isolated
supply, a supply that is floating from ground. In some half-bridge applications
the –HV node would actually connect to ground, and if that ground is not
isolated from the side 1 GND1, a non-isolated supply could be used on the low
side. The high side often needs a separate supply to be isolated from the low
side. In some cases, the high side may not need an isolated supply, but can be
bootstrapped from the low side supply with a high voltage diode to charge the
bypass capacitor on the high side between VDDA and GNDA.
In regards to the application example on page 9 of ADuM1230 datasheet (Rev B),
the ADuM1233 can use the same buffer circuit shown in the ADuM1230 datasheet,
it was just omitted when the datasheet was made.