REG113: Overdrive NR input

Michael Daimer

Part Number: REG113
Other Parts Discussed in Thread: LM317

Tool/software:

Hello experts,

With REG113EA-5/250, can the internal reference of Error Amplifier be override externally so that the voltage at the output can be adjusted?
The aim is to set the voltage at the output between 1…5V (or better 0…5V).
With the REG113, the NR input has drawn a relatively large amount of current.

Best regards,

Michael

1 month ago

+1 Daniel Esparza 1 month ago

TI__Expert 3805 points

Hello Michael,

The NR pin is intended for noise reduction purposes only. The internal reference cannot sink any current, so driving the pin externally is not recommended as it can cause permanent damage.

I recommend an adjustable regulator like the LM317 instead (https://www.ti.com/lit/ds/symlink/lm317.pdf), where you can control the output by driving the adjust pin. In section 8.3, you will find examples of different possible configurations.

Regards,

Daniel

0 Michael Daimer 1 month ago in reply to Daniel Esparza

TI__Intellectual 1725 points

Hi Daniel,

thanks for your explanation.

The purpose of initially choosing REG113 is, that it works without output capacitor. The application should be able to change very quickly the output voltage without needing to wait of Vout discharge/charge. The average load is 10-20mA, but peaks can go up to 250-3350mA as well.

Do you have any recommendation, which works with very little output capacitance (100nF) at 20mA load?

Thanks and best regards,

Michael

+1 Daniel Esparza 1 month ago in reply to Michael Daimer

TI__Expert 3805 points

Hello Michael,

The parametric tool in our website is a great aid. You can filter for the specific conditions you are looking for.

Please visit this link for possible options that may meet your needs:

Linear & low-dropout (LDO) regulators product selection | TI.com

Regards,

Daniel

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REG113: Overdrive NR input