ESP8266 Community Forum

The drawback from using only a buck converter is that it needs to be set to 3.3 V very carefully using a very small trim pot. When finally on the spot, it can easily set off-spot due to dust, shocks etc. And then it may give a voltage way too high for the esp, destroying it. That's why I like to have a fixed lineair regulator in between.

eriksl wrote:The drawback from using only a buck converter is that it needs to be set to 3.3 V very carefully using a very small trim pot. When finally on the spot, it can easily set off-spot due to dust, shocks etc. And then it may give a voltage way too high for the esp, destroying it. That's why I like to have a fixed lineair regulator in between.

There is a great little switching regulator board out of China called mini360. I have used it in a number of products I have designed. It uses a trim pot. But I have that removed and replaced with a fixed resistor for the same reason as you stated.

I imaging some customer having a problem with the product and him going in and turning it to try and make it work. In the past when I have needed to us trim pots I have had production use nail polish to lock the position in place.

I also use nail polish, but it doesn't help against dust and corrosion. Best solution, indeed, is to use a fixed resistor (or even better: a zener). Or an additional linear regulator.

I think the advantages of using a switching voltage regulator vs linear ones are pretty obvious: higher voltage input, high efficency, low heat dissipation, etc. As we are talking about digital devices here not some high precision analog stuff, for a good designed switchmode voltage regulator it really makes no difference vs linear ones in terms on noise.

I am using all the time fixed value resistors calculated for the desired Voltage output.

In more than 25 years of playing with I have seen more catastrophic Linear regulators failures than SW ones.