If you can miss 0.3V you can add +/- 14.7 adjusted uLDO regulators. LT3032 would be compact and low noise. I have a DAC with such a DC DC converter followed by CLC and I have to admit that it is silent (even without LDOs!) due to the opamps PSRR. If you search you'll find affordable ones, it was just an example. I initially offered an ultra compact free one in my post but that one unfortunately is 5V input.
The +/- 50V won't be ripple free either I guess 🙂
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Whatever the technobabble the facts are that dropping 35V at 100 mA will be 3.5W per power supply side lost to useless heat. This times 2. That is 7W of continuous heat generated in your car device besides the already generated heat. With 200 mA it will be 14W in total which is simply stupidity by design for this specific purpose.
Even if one divides this 7W in 7 parts of 1W it still will be 7W. Quite unelegant designing and possibly a self inflicted problem as car devices are not large and environmental temperature possibly is high too. Not generating heat is to be preferred whatever the angle is from which one is looking at this issue.
Another way to look at things is to use single supply 12...14V from the car battery and add an uLDO to that set at 11V and have virtual GND + coupling caps + rail to rail opamps. Or to have the power amplifier having enough gain to not even need an active preamp which is the ideal solution really 🙂
Even if one divides this 7W in 7 parts of 1W it still will be 7W. Quite unelegant designing and possibly a self inflicted problem as car devices are not large and environmental temperature possibly is high too. Not generating heat is to be preferred whatever the angle is from which one is looking at this issue.
Another way to look at things is to use single supply 12...14V from the car battery and add an uLDO to that set at 11V and have virtual GND + coupling caps + rail to rail opamps. Or to have the power amplifier having enough gain to not even need an active preamp which is the ideal solution really 🙂
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Just on the high voltage LDO - look up Maida style regulators, using a mosfet to sit the LDO in a small voltage drop.