How to design Vout=0.3V @ 20mA circuit

Dong Shen

Prodigy 400 points

Other Parts Discussed in Thread: TLV707, TPS546D24, TPS62821, TPS62806

Hi, Team

My customer needs to design Vout=0.3V @ 20mA circuit. The requirement is:

1. Vin = 3.4V-4.5V

2. Vout = 0.3V @ 20mA

3. Solution size: as small as possible

Could you help on it? I think it is needed to add some external circuits for current buck/LDO devices.

Thank you.

over 6 years ago

0 Jose Gonzalez Torres over 6 years ago

TI__Intellectual 1146 points

Hi Dong,

Unfortunately many of the LDOs only go to 0.5V outputs or higher. However you could use a resistor divider to further reduce this voltage.

For LDOs: A device like TLV707 which is a available in a 1mm x 1mm package (X2SON) with a 0.85V output (TLV707085DQNR).

Do you have an accuracy target for the 0.3V rail?

TLV707085DQNR

0 Dong Shen over 6 years ago in reply to Jose Gonzalez Torres

TI__Prodigy 400 points

Hi, Team

Is Buck circuit able to solve this problem?

Thanks.

0 Jose Gonzalez Torres over 6 years ago in reply to Dong Shen

TI__Intellectual 1146 points

Daniel,

I would defer to our team in bucks to give you a good recommendation. However looking at the product selection search it seems we have some controllers that could help with this conversion:

http://www.ti.com/power-management/non-isolated-dc-dc-switching-regulators/step-down-buck/products.html#p238min=1;3.4&p238max=4.5;100&p634min=0.1;0.3&p634max=0.3;92&p451max=0.02;420&p32=1;1&p212max=24.39024390243903;100&sort=p1130;asc

If you need a converter and not a controller; TPS546D24 is the only one i could find.

0 Chris Glaser over 6 years ago

TI__Guru**** 150830 points

Hi Daniel! I hope you're doing well.

The TPS62806 supports Vouts down to 0.4V. If you need lower, you need to feed a voltage into the FB pin on a device like TPS62821/5. I will email you some preliminary documents on this topic. Here are 2 older ones:

http://www.ti.com/lit/an/slva251/slva251.pdf

http://www.ti.com/lit/an/slva419b/slva419b.pdf

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How to design Vout=0.3V @ 20mA circuit