LM5122ZA: Step-up (boost) regulator recommendation inquiry

Hi JH,

Thanks for reaching out. Would you not have any other parameters specified by your customer like: targeted efficiency, price, noise performance, frequency, need for galvanic isolation? Furthermore, is there a particular reason why you specifically mentioned the LM5122ZA?
Please offer us all of the information available to you so we can give the most appropriate proposal for your application.

Thank you and best regards,
Bryan

Hi Bryan,

The customer said that other parameters do not matter as long as the product can support the conditions below.

   - VIN = 3V ~ 5V

   - Vout / Iout = 12V / 10A

If there is a product from TI that can design the above power supply, please recommend it.

Thanks,

JH

Hi Niklas,

Thanks for your reply.

The example design is only confirmed for VIN > 5V on the product webpage for the LM5123-Q1.

If you have any example design data similar to the customer’s use case of VIN=3V, VOUT=12V, please share it.

BR,

JH

Hi JH,

Unfortunately I do not have a reference design for LM5123 with Vin 3V-5V rating.
The important parts to check here are the FETs.
While Vin is below 5V, the VCC voltage will follow the input voltage:

This means the driver voltage for the FETs will also be lower.
Please make sure the FET gate voltage threshold is low enough that the FETs will still fully turn on at worst case VIN of 3V.

Best regards,
Niklas

Hi Niklas,

Thanks for you help.

Could you please recommend a suitable FET?

Best Regards,

JH

Hi JH,

I am not a FET expert, so I cannot give an ideal part recommendation here.
In general, logic level FET should perform better here, as their gate plateau is lower.
Manufacturers normally have a filter search, where customer should be able to find a suitable logic level FET with suitable voltage and current ratings.

Best regards,
Niklas