LM3102: LM3102

Hans van Egdom

Part Number: LM3102

Designing a new power step down voltage regulator.

We need a very low noise 5-volt power supply, approx. 20 - 30 uVrms

Input 12 volt (stable) max 2,5A, operating temp range approx. 30ºC 40ºC

I tried to find a regulator in the LDO voltage regulator section, those regulators are not capable to handle above specs.

I tried to make a design with webench tool with the LM3102, UL3836, tps563200DDCR. By simulating those designs, the load transient is too high.

Is it possible to point me in the right direction to make a choice for a good regulator?

Best regards Hans. (the Netherlands)

over 4 years ago

0 Samuel Jaffe over 4 years ago

TI__Mastermind 25590 points

Hans,

For extremely low output noise applications I'd recommend a 2-stage solution. A buck step-down to an LDO. The buck can regulate to a voltage just above the LDO output so the LDO does not dissipate as much heat.

-Sam

0 Hans van Egdom over 4 years ago in reply to Samuel Jaffe

Prodigy 40 points

Hi Sam,

Thanks for the answer, l am thinking at the following configuration. I will start with a LM5116mh (Emulated current mode), with the webench simulation, the load transient ripple is just about 120mVrms, after that I can use an LDO, or a 2stage lowpass filter. (power tip 54/55)

Are there other step-down regulators with lower noise level (other than LDO)?

Best regards Hans.

0 Samuel Jaffe over 4 years ago in reply to Hans van Egdom

TI__Mastermind 25590 points

Hans,

An LDO will be your best option for low noise. Here's a list of our low noise LDOs.

-Sam

Power management

Power management forum

LM3102: LM3102