L5970AD DCDC schematic doubt
Hello,
I am investigating in using L5970AD DCDC converter for a 12VDC to 3V3 need.
It was advised to me by the ST DCDC online simulator.
It's a 20 year old circuit but it it matches the budget, the additional BOM and the efficiency so I am interested.
But I don't reach in answering some questions. If one of you can share some return of experience about this chip I am gladly listening.
I am in design phase, looking datasheets, and except error I don't find my answers :
- The VREF signal is noticed as 3V3. 3V3 is the output I want to create. On the Typical application schematic it seems not clear for me if connecting VREF to the output is okay, or if we need a precursor 3V3 ??? Should we supply a high impedance 3V3 from resistor divided input for example ? I couldn't reach advise about it, the is no paragraph about VREF. Is it an input or an output? What about generating 5V, do we need a 3V3 rail ?
Also, even if switching frequencies are different, why not group L5970AD and L5970D in one unique datasheet ?
Thank you for reading,
A++ Alex
