TPS3808-Q1: Request TPS3808 Circuit Review

choi donghun

Prodigy 100 points

Part Number: TPS3808-Q1
Other Parts Discussed in Thread: TPS3808,

Hello, I am an engineer working for a company called Partron in Korea.
I'd like to ask for a circuit review of TI.

I attached the PDF.

#Specifications used
-. 23.5 mS Delay
-. Vcc Voltage 1.8 V

#Questions
-. Overall circuit modifications

TI_DR_TPS3808.pdf

Thank You!!

over 4 years ago

0 Abhishek Wadhwa over 4 years ago

TI__Intellectual 1135 points

Hi,

The C117 value for 25ms delay is incorrect. Please refer to Section 8.3.4 Selecting the Reset Delay Time of TPS3808-Q1's datasheet for the equation.

Why is MR pin connected to 1.8V? Do you want the device to have an always on reset?

Best,

Abhishek

0 Abhishek Wadhwa over 4 years ago in reply to Abhishek Wadhwa

TI__Intellectual 1135 points

Hi,

Do you have an update for me to review?

Best,

Abhishek

0 Ben C over 4 years ago in reply to Abhishek Wadhwa

TI__Guru 56345 points

Hi Choi,

I believe you may have swapped the numbers when mentioning 23.5ms for time delay. Did you mean to type 32.5mS? According to the calculation, the time delay is 32.5ms.

Also, I would add a bypass capacitor on the VDD pin. Please place this capacitor as close as possible to the VDD pin.

The rest of the schematic looks good to me.

Thanks!

Ben

0 choi donghun over 4 years ago in reply to Abhishek Wadhwa

Prodigy 100 points

Sorry, we are currently undergoing an internal review. I will give you a revised version when the review is completed. And I want to design to start resetting once 1.8V starts, is it correct to NC process MC pin?

Best,

Choi

0 Abhishek Wadhwa over 4 years ago in reply to choi donghun

TI__Intellectual 1135 points

Hi Choi,

Did you mean no connect MR pin?

Best,

Abhishek

0 choi donghun over 4 years ago in reply to Abhishek Wadhwa

Prodigy 100 points

That's right. I'd like to reset it after 30ms after the 1.8V is turned on.

0 Ben C over 4 years ago in reply to choi donghun

TI__Guru 56345 points

Hi DH,

Are there any other question we can assist you with your design? If not please click on "resolved" to close the thread. Good luck to you!

Ben

0 choi donghun over 4 years ago in reply to Ben C

Prodigy 100 points

I want to design to start resetting once 1.8V starts, is it correct to NC MC pin?

Choi

+1 Ben C over 4 years ago in reply to choi donghun

TI__Guru 56345 points

Hi DH,

I am a bit confused. Do you want the output of TPS3808 to go low once the 1.8V is up and running? Also, are you referring the "MC" pin as the MR pin? See below:

The way the TPS3808 operates is that when the SENSE pin is above VIT + VHYS, the output of /RESET will go high which is deemed as a deasserted state. If the SENSE pin detects the monitored voltage going below the voltage threshold (VIT), the /RESET output will go low which means asserted.

Is the operation that I have described above what you are seeking in your design/application?

Ben

0 Ben C over 4 years ago in reply to Ben C

TI__Guru 56345 points

Hi Choi,

Are there any new updates? If not and you are pleased with the answers that I have provided, please feel free to close the thread by clicking on "resolved". Thanks and good luck to you!

Ben

0 choi donghun over 4 years ago in reply to Ben C

Prodigy 100 points

I'm sorry I'm too late. I solved it thanks to you. Thank you.

0 Ben C over 4 years ago in reply to choi donghun

TI__Guru 56345 points

Hi Choi,

No worries! Glad that you were able to solve your issue. Good luck to you!

Ben

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TPS3808-Q1: Request TPS3808 Circuit Review