XTR111-2EVM: Schottky Diode Requirement

Suraj Prajapati

Intellectual 255 points

Part Number: XTR111-2EVM

Hello Sir,

Greetings!!

I have a question regarding the use of Schottky Diode D1 (SS16-E3/5AT) as shown in following figure.

I did not understand the use of Schottky diode in reverse bias with VSP rail while VSP is 24V.

Kind Regards

Suraj

over 5 years ago

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi Suraj,

D1 prevents the drain of Q3 and associated circuitry to become more positive than VSP. It protects the circuit when an overvoltage (surge, burst, ESD, etc.) is hitting the output line.

Kai

0 Tamara M Alani over 5 years ago

TI__Genius 10850 points

Hi Suraj,

Thank you for your question. Kai is correct. I will mark this as resolved.

-Tamara

0 Suraj Prajapati over 5 years ago in reply to kai klaas69

Intellectual 255 points

Hi Kai,

Thanks for your reply.

But I am still confused, what if the voltage at Anode of D1 is greater then VSP. The diode becomes forward biased and it will damage the VSP supply voltage and all the circuit associated with it.

Please guide me further.

Thanks & Regards
Suraj

0 kai klaas69 over 5 years ago in reply to Suraj Prajapati

Guru 140200 points

Hi Suraj,

surge, burst and ESD are short lasting. C1 and the other decoupling caps will absorb these transients.

Kai

0 Suraj Prajapati over 5 years ago in reply to kai klaas69

Intellectual 255 points

Dear Kai,

Thanks for you reply.

If diode absorbs surge, burst and ESD, can't we just use Decoupling Capacitor instead of diode?

Best Regards,
Suraj

0 kai klaas69 over 5 years ago in reply to Suraj Prajapati

Guru 140200 points

Hi Suraj,

the Schottky diode also helps against inductive kick backs, if an inductive load (cable) is connected to the output line.

But, why are you opposing this Schottky diode so much??

Kai

0 Suraj Prajapati over 5 years ago in reply to kai klaas69

Intellectual 255 points

Hello Kai,

Thanks for your valuable feedback. This is really helpful.

Best Regards,
Suraj

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XTR111-2EVM: Schottky Diode Requirement