5V Clean power supply - very small area - Need for a Buck-Boost regulator ?

Shmuel Davis

Other Parts Discussed in Thread: TPS63810, TPS63031, TPS63002

We have a design where we receive +5V supply from a PC power supply. We need to regulate this supply to provide a very clean +5V to our ADC \ DAC front end. We expect the absolute maximum current drawn will be 50mA. The PC power supply spec is meant to give +5V +/-5% (+4.75V to +5.25V). We are not able to use a LDO as one of our components has a min supply voltage requirement of +4.7V(we would need a LDO with a Max dropout voltage of 50mA - which I don't think exists ?). Thus as far as I can see we are left with Buck-Boost DC\DC or something similar ?

We have very little room and need the cleanest possible +5V supply in the smallest possible PCB area. Possibly we should take a device that has a spec of 80-100 mA just for headroom but if there is a difference in solution area we could go down to 50mA ? Can you help us ?

over 5 years ago

0 Helen chen over 5 years ago

TI__Mastermind 40080 points

Hi Davis,

Yes, you need a buck-boost converter.Like TPS63810.

By the way, what about the volume of this project?

0 Shmuel Davis over 5 years ago in reply to Helen chen

Expert 2930 points

Dear Helen Chen,

Thank you for your reply.

This is a new project so the yield is unkown. But it could be between 100 - 1K

Will the TPS63810 give me the smallest design solution ? What do expect the total PCB area will be ?

The Max current I expect is between 50mA - 100mA !

What type of voltage ripple do you think we would receive from this solution ?

I doubt I will have room to add a LDO to the output to clean the ripple ! Do you have any integrated designs - what type of area would this take ?

Thanks for all your help !

Best regards

Shmuel

0 Helen chen over 5 years ago in reply to Shmuel Davis

TI__Mastermind 40080 points

Hi Shmuel,

the estimated ripple will be around 50mV.

What is the ripple requirement at your side?

0 Shmuel Davis over 5 years ago in reply to Helen chen

Expert 2930 points

Dear Helen,

What total PCB solution size do you expect for this component (including all the external components !)

Note I can go with a reduced size inductor since I only need 50mA - 100mA !

Do you have any other options without the I2C interface with lower current spec, fixed +5V output that will give me a smaller solution ?

Best regards

Shmuel

0 Helen chen over 5 years ago in reply to Shmuel Davis

TI__Mastermind 40080 points

Dear Sir,

Please take a look at TPS63031. This is non-I2C silicon. You can achieve lowest size with it.

Suggest to apply for an EVM board and have a test on the part.

0 Shmuel Davis over 5 years ago in reply to Helen chen

Expert 2930 points

Dear Helen,

Thank you for your suggestion TPS63031. Do you have anything similar but with a fixed +5V output that could save on resistor divider ? Also I need MAX 100mA ONLY and don't need the 800mA output current - do you have anything that could give me a smaller solution ?

Best regards

Shmuel

0 Helen chen over 5 years ago in reply to Shmuel Davis

TI__Mastermind 40080 points

Dear Sir,

Please take a look at TPS63002.

0 Shmuel Davis over 5 years ago in reply to Helen chen

Expert 2930 points

Dear Helen,

Thank you for the suggestion. The TPS63002 is much closer to what I am looking for.

However we have in stock and a design using a ADP2504 that gives me an approx PCB area of 8mm x 6mm. It has upto 1A output current. I was hoping to find something that had a lower spec (we need a MAX of 100mA and maybe only 50mA) and thus maybe give me a smaller PCB area ?

Best regards

Shmuel

0 Helen chen over 5 years ago in reply to Shmuel Davis

TI__Mastermind 40080 points

Hi Shmuel ，

For the 5V fixed output version IC, TPS63002 is already the smallest solution. Suggest you use a small inductor to get small size.

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5V Clean power supply - very small area - Need for a Buck-Boost regulator ?