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ADUM130E1BRWZ is dropping pulses

Category: Hardware
Product Number: ADUM130E1BRWZ

I have a problem with the ADUM130E1BRWZ. I am designing a half-bridge circuit and using this circuit to isolate my signals. The signals are generated from a microcontroller, it is a PWM signal, frequency 100 kHz. The output of the ADUM130E1BRWZ is connected directly to the half-bridge driver. The signal on the input to ADUM130E1BRWZ is ok, but the ADUM130E1BRWZ keeps dropping some pulses. This happens only on one of the channels (channel HIN in the schematic). I have checked the voltage with an oscilloscope on the enable and VCC, both are straight DC voltages, no voltage drops there. Attached is a partial schematic, PCB and oscilloscope measurement (Ch1 is input, Ch2 is output from the ADUM. The problem appears even when the half-bridge is not powered, even when the half-bridge driver is unsoldered from the PCB and hence the ADUM130E1BRWZ is not loaded with anything. So I think it can´t be interference from the half-bridge. The problem does not appear all the time, but when it happens it happens with a frequency of about 7.5 kHz. The used oscilloscope has all channels galvanically isolated.
Please any ideas what could be the cause and how to solve the problem ?

  • ADI North America will be on summer shutdown starting August 24, 2023; perhaps another community member can assist you until our return on September 5th.
  • Hi,

    The ADuM130E1 is an On-Off Keying (OOK) architecture and it is a default high variant. That means the VIB input channel's transmitter is active when the input low. It also means the VOB output will only be low when it detects the transmitters signal. This implies the VIB is continuously seeing a low input for the duration of the pulse.

    I might look for a cold solder joint first. Maybe try probing the VIB input signal directly at the shoulder of the pin to see if the isolator is actually getting the expected input.