Is it unheard of to be a mixed signal design engineer? Or do you usually have to polarize to analog or digital?

Speaking as someone that did full-custom mixed-signal ASIC design work for nearly two decades, I'd say that the answer to the first question is no. As for the second question, I would say that most people stay in one camp or the other (by and large). There are demons in mixed-signal work that most people would rather not deal with.

 

Cool, thanks for the replies.

One more question since it was brought up; is firmware usually written by the EEs who designed the product rather than SEs? Is it usually written in assembly?

Depends on how big the project and/or company is. In larger companies or larger projects, you usually have different teams doing each.

As for the language, that also depends on the features of the hardware. If it is a CPLD or FPGA, it is likely done either via schematic capture or an HDL such as Verilog or VHDL. If it is a microcontroller that is extremely resource starved, then it will probably be in assembly. But most micros today have the resources to handle programs written in C. I think (and it's a supposition on my part) that all other languages for firmware development combined make up a very small fraction of the code base.

 

For me I design powersupply's from scratch most of them are custom design.
We still use a lot of analog controllers. 2 years ago we started to research the digital control loops but until now we only made a boost converter with it. The analog way was still the cheapest.

The output and a part of the safety of the powersupply is controlled by software and it is written in assembly.
We don´t use a program guy but we also write the program by our self.

But we still need analog engineer to design the units, the only problem is that there are not many people that want to learn this stuff anymore.