At this moment we have designed a PCB for a customer where we use 3x TPS62133A for generating 3 different +5V supplies out of +12V. For the input we use a 10uF/25V/X7R/1206 cap in parallel with 100nF and at the output a 22uF/10V/X7S/0805 ceramic cap at each converter as recommended in your datasheet.
However according our PCB supplier and other manufacturers there are hugh problems worldwide with the availability of MLCC caps especially with large values and larger packages. Because our customer wants to transfer to volume production this could mean that we have delivery problems when the availability of these capacitors remains bad. They recommend to use small size packages for MLCC like 0402 or 0201 but large values like 22uF or 10uF are very limited at this moment.
Another option to avoid this problem could be use of polymer caps but I was wondering if this would have impact on the efficiency of the TPS62133 when we would decide to change the input and output caps to polymer instead of ceramic caps? The advantage of polymer is that the capacity remains almost the same at higher voltages where the capacitance of ceramic caps is reduced at higher voltages. The ESR of a 10uF/25V or 22uF/20V polymer cap that could use as replacement is max 30mOhm at 100kHz.
Please could you give us some advice for this?
Best regards,
Chris van der Aar
NTS Systems Development
Eindhoven, The Netherlands
