4 ms·

For what it's worth in hobby projects it's time to throw linear regulators into the dustbin. There's 7805 pin-compatible switching modules now! Stuff like this

For what it's worth in hobby projects it's time to throw linear regulators into the dustbin. There's 7805 pin-compatible switching modules now! Stuff like this. [1] [1] https://www.digikey.com/en/products/detail/cui-inc/VXO7805-500/7350288 https://www.digikey.com/en/products/detail/cui-inc/VXO7805-5...

stephen_g 4y ago
Depends on what you're doing. For a lot of sensors and things you might want the power-supply ripple rejection (PSRR) you get through an LDO. I'm not doing hobbyist things, but in our designs we have a lot of places where we will have a switcher that generates an intermediate voltage to feed a bunch of ultra-low noise, high-PSRR LDOs for different components (isolates them from each other too). This is RF though, where that is especially important.
- arcticbull 4y ago
  I just meant as a replacement for your main input power regulator - for the 7805 way too many people still use. You are absolutely right that there is a role for LDOs in modern devices. There's no reason for most hobbyists to be using super hot, super inefficient and super constrained high-dropout linear regulators from 1972 when there's a pin-compatible all-in-one switching module for roughly the same price. To pull more than a couple hundred mA at the lowest voltage differential you need a heatsink!
  - sidewndr46 4y ago
    Trying to use a switching regulator for everything becomes a complete nightmare when you have to debug a circuit. You scope something that should be a square wave or similar and it has the switching frequency of the regulator superimposed upon it everywhere.
  - crote 4y ago
    Most people don't even use input power regulators. 5V wall warts are dirt cheap due to USB charging and provide the exact voltage you need. Why mess around with a 7805 when you already have a dozen 5V power supplies lying around the house?
    - arcticbull 4y ago
      Unless it's a USB power adapter - which is a good choice, btw - I'd be very wary about what's coming out of that 5V no-name wall wart. That power can look like ass and not be close to 5V. If you're doing that an LDO isn't a bad choice.
83 4y ago
90% efficiency for $2.50ish. Pretty cool, thanks for making me aware of these.
- blihp 4y ago
  IIRC, you can get them for ~$1 on aliexpress. They're handy little devices.
squarefoot 4y ago
Linear regulators are still preferable when very clean supply and no spurious RF radiation are needed. Filters and screens can be easily added so that one gets both high efficiency and clean output, but they add to the cost and size.

stephen_g 4y ago

Depends on what you're doing. For a lot of sensors and things you might want the power-supply ripple rejection (PSRR) you get through an LDO. I'm not doing hobbyist things, but in our designs we have a lot of places where we will have a switcher that generates an intermediate voltage to feed a bunch of ultra-low noise, high-PSRR LDOs for different components (isolates them from each other too). This is RF though, where that is especially important.

arcticbull 4y ago
I just meant as a replacement for your main input power regulator - for the 7805 way too many people still use. You are absolutely right that there is a role for LDOs in modern devices. There's no reason for most hobbyists to be using super hot, super inefficient and super constrained high-dropout linear regulators from 1972 when there's a pin-compatible all-in-one switching module for roughly the same price. To pull more than a couple hundred mA at the lowest voltage differential you need a heatsink!
- sidewndr46 4y ago
  Trying to use a switching regulator for everything becomes a complete nightmare when you have to debug a circuit. You scope something that should be a square wave or similar and it has the switching frequency of the regulator superimposed upon it everywhere.
- crote 4y ago
  Most people don't even use input power regulators. 5V wall warts are dirt cheap due to USB charging and provide the exact voltage you need. Why mess around with a 7805 when you already have a dozen 5V power supplies lying around the house?
  - arcticbull 4y ago
    Unless it's a USB power adapter - which is a good choice, btw - I'd be very wary about what's coming out of that 5V no-name wall wart. That power can look like ass and not be close to 5V. If you're doing that an LDO isn't a bad choice.

83 4y ago

90% efficiency for $2.50ish. Pretty cool, thanks for making me aware of these.

blihp 4y ago
IIRC, you can get them for ~$1 on aliexpress. They're handy little devices.

squarefoot 4y ago

Linear regulators are still preferable when very clean supply and no spurious RF radiation are needed. Filters and screens can be easily added so that one gets both high efficiency and clean output, but they add to the cost and size.