TPS62840: ESD diode for Input pins.

Ashok R41

Part Number: TPS62840
Other Parts Discussed in Thread: TVS0500, ESD321, ESD351, TPD1E10B09-Q1

Hi,

We are using TPS62840 in our device to step down 6V to 3.1V. we are using 2 x 3Volt batteries, the batteries will be replaced by end-user therefore ESD diode is a requirement. According to datasheet maximum voltage at the input is 7V. ESD diodes used for GPIO have clamping voltage greater than maximum voltage rating. similarly, what is the suggested clamping voltage and breakdown voltage of ESD diode with operating voltage 6.5V(0.5V ceiling due to extra 0.1-0.2V of new batteries)?

Regards

Ashok

over 5 years ago

0 Chris Glaser over 5 years ago

TI__Guru**** 151340 points

Hi Ashok,

Let me loop in our ESD people for their comment.

It would be best if the voltage were kept below 7V, but I am not sure if there is a precise enough ESD device for this.

0 Ashok R41 over 5 years ago in reply to Chris Glaser

Intellectual 360 points

Hi Chris,

Thank you for the response. I have found PESD6V5C1USF, let me know if this can be used.

Regards

Ashok

0 Chris Glaser over 5 years ago in reply to Ashok R41

TI__Guru**** 151340 points

Hi Ashok,

That ESD diode looks more appropriate for signals lines, but I believe you want to protect the power (VIN) line to the TPS62840? Which pins would be connected to the battery and need ESD protection?

The TVS0500 looks like it can fit, but let's wait for the ESD people to reply. It may be a few days due to the holiday.

0 Ashok R41 over 5 years ago in reply to Chris Glaser

Intellectual 360 points

Hi Chris,

Vin and enable pins of TPS62840 is connected to the battery. The ESD diode will be placed near to the battery holder. So, enable pin will also be protected.

The input voltage (6V) falls between Vrwm and Vbr, so the proper functioning of the ESD diode might not be guaranteed. We cannot afford to have leakage current as the device is battery operated.

Regards

Ashok

0 Chris Glaser over 5 years ago in reply to Ashok R41

TI__Guru**** 151340 points

Thanks for confirming.

You might add a 10k between the battery and EN pin to insulate the EN pin a bit more.

Hopefully, the ESD people are back next week and can comment.

0 Ashok R41 over 5 years ago in reply to Chris Glaser

Intellectual 360 points

Hi Chris,

Yes, will add 10K Ohm resistor between EN pin and battery.

Regards

Ashok

0 Cameron Phillips over 5 years ago in reply to Ashok R41

TI__Genius 12410 points

Hello,

ESD clamping voltage is different than the abs maximum rating because the transient happens so fast. Even the internal ESD protection clamps higher than the absolute DC maximum voltage. The way to know what the absolute correct clamping voltage should be is to run TLP on the device and see where it breaks. However, we do have ESD diodes like the ESD351 ESD321 that are single channel and will clamp very low and should be able to work as long as the VRWM of 3.6V is acceptable.

For more information about ESD please see our training videos.

0 Ashok R41 over 5 years ago in reply to Cameron Phillips

Intellectual 360 points

Hi Mr.Cameron,

Thanks for the response. In this case, we are using 2 x 3V battery, the operating voltage is 6V. We cannot use ESD351 or ESD321 please recommend ESD diode for the same.

Regards

Ashok

0 Ashok R41 over 5 years ago in reply to Cameron Phillips

Intellectual 360 points

Hi Mr.Cameron,

I guess TPD1E10B09-Q1 can be a good fit for this case.

Regards

Ashok

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TPS62840: ESD diode for Input pins.