Hi,
my customer is using ISO7740F as below in an isolated DCDC(phase shift full bridge).
F28069 is placed in the secondary side, and the PWM will drive half bridge gate driver in the primary side and the isolation is achieve through ISO7740F.
Primary side supply of ISO7740F is 3.3V, secondary side is 5V. 100ohm and 100pF applies to all four channels(I just draw one channel)
But we will observe below waveforms:
light blue: INA, dark blue- OUTA, purple- gate driver output corresponding to OUTA.
We can see that OUTA does not respond to INA correctly. We measured the 5V and 3.3V supply of ISO7740 is stable during the period.
This may happen for all four channels.
What may be the cause?