Part Number: ISO7740
The TI ISO7740 isolator does not work properly, loses the signal, and the silionlab si8645ba can work properly. Please help analyze the reasonNote: the transmission is the pulse signal, the signal rate: 30MHz, the GND_F voltage variation amplitude -40V--0V, frequency: 50kHz
In reply to Koteshwar Rao:
The pulse width >10ns,
Look at the schematic diagram of my drawing. The first set of signals can be transmitted completely, but the three groups of signals are missing.
This problem should not be related to the pulse width.
Is it related to the negative voltage disturbance superimposed on the GND_F floating ground?
In reply to bunney shang:
the pulse width>20ns,
the slew rate of this negative voltage disturbance: 50V/us
Vcc1: 3.3V Vcc2: 3.3V
it is being observed on multiple devices / PCBs
In reply to kai klaas69:
the values of decoupling caps is 0.1uF.
two channel scope plot：Ch 1:signal Ch 2:GND_F
The right signal wave ：
The Wrong signal wave ：
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