BTS50055-1TMA: Ripple on IN (Pin 3) with Resistor

[Sebastian_393]

I'm using the BTS50055-1TMA as bipolar switch.

If EN_Extern is 3,3V there is a ripple on pin 3 even if I reduce R1/R3 to 1kOhm.

Is this normal?

Regards

Sebastian

[Meghana]

Hello Sebastian,

The resistance between IN to GND pin is recommended to be <0.5kohm during turn on. Can you please try reducing the value of R1/R3 further more and check. Also please share us the measurement waveform to analyze the issue further. 

Regards

Meghana R

[Sebastian_393]

Hello Meghana,

here are the screenshots from the scope. I've tried 10kOhm, 1kOhm and 470Ohm for R1/R3.

10kOhm:

1kOhm:

470Ohm:

Best Regards

Sebastian

[Sebastian_393]

Hello Meghana,

here are the screenshots from the scope. I've tried 10kOhm, 1kOhm and 470Ohm for R1/R3.

10kOhm:

1kOhm:

470Ohm:

Best Regards

Sebastian

[Meghana]

Hello Sebastian,

As you would have already noticed, the ripple has reduced substantially with the resistance values. To further optimize the design, we request you to also share the measurements of EN_Extern and voltage drop across R1 or R3. And could you also try using 100 ohm for R1 & R3 and share us measurements. 

Regards

Meghana