Hello ,I have a question about transition when ADuM3224 was powered on.The VDD1 is powerd on before VDDA(VDDB), and the VDDA(VDDB) is powered on after VDD1.VDDA is powered on after VDD1 more than 100ms later.The VOA(VOB) will be setup with some delay from VDDA powered on.This "Delay" is indicated as 50 us in the tabel-13 of the datasheet.Our customer is using two ADuM3224 to drive a full-bridge circuit.This customer has a concern about variation of this delays , because if the VOA delay and the VOB delay has a difference the balance of full-brigde may lose.So the customer wants to know the maximum delay that are possible.I know this delay is not guaranteed value, but, we wish to know the maximum delay which is occurring possible.Do you know the maximum delay from input VDDA(VDDB) to output VOA(VOB)?
I apologize for the late reply.
The ADuM3224 delay from VDDA(VDDB)to VOA/B is approximately 50 µs as mentioned in Table 13 of the datasheet. This number was obtained through bench measurement, slightly derating the 45 µs typically observed. To create this number, a very fast edge rate on VDDA(VDDB) had to be supplied. This could be similar to how a bootstrap first charging cycle could power the device. If a normal benchtop voltage source is used to charge VDDA(VDDB), the ramp rate of the voltage supplies is usually very slow compared to the approximately 45 µs delay on startup for powering VDDA(VDDB).
If the customer has a very fast edge rate, it is possible to get delays up to around 50 µs. If the edge rate is more similar to how many isolated power supplies charge up, getting the exact instant the UVLO triggers until when the output is valid is hard to tell.
Since this metric is not measured in production, it is hard to give a definitive answer, but if the customer wants a number to work around, we could say we don't expect the longest delay to be longer than 100 µs after VDDA(VDDB)goes above the rising edge of the secondary side UVLO (more than doubling the typical value we see on the bench).
Thank you for your support.
This morning, I informed your answer to the customer and his concern was cleared.