Just a simple question of opinion here. Would you say that using a LM7810 10V linear regulator that gets its input voltage from the battery in a vehicle is cutting it kind of close, given that generally input voltage needs to be maintained at 2V over output voltage. I mean, realistically, even when a car is off, as long as the battery isn't on its last leg, they usually have 12.3V or better, and my circuit isn't designed to operate with the vehicle off. My truck seems to maintain a steady 14.6V while running.
I can get away with 9V regulator (lm7809) I would prefer 10V as it would make things easier for me.
What do you guys think?
Edit: As an after thought, let me add another question. Using the TO-220 package with a heat sink (regulator gets pretty hot but stays within limits), the package takes up a lot of space on the board (board is low-profile so the TO + heatsink lay flat on the PCB). The SMT version of the regulator takes up less space, but I'm concerned about heat distribution using nothing but a copper area under the device on a single sided 1oz board. Thoughts on this as well would also be much appreciated. I'd prefer the DPAK if I can get away with it.
To answer any questions about airflow, it will be in open air (enclosure has several air vents) but no fan or anything, mounted inside the passenger cabin.
I can get away with 9V regulator (lm7809) I would prefer 10V as it would make things easier for me.
What do you guys think?
Edit: As an after thought, let me add another question. Using the TO-220 package with a heat sink (regulator gets pretty hot but stays within limits), the package takes up a lot of space on the board (board is low-profile so the TO + heatsink lay flat on the PCB). The SMT version of the regulator takes up less space, but I'm concerned about heat distribution using nothing but a copper area under the device on a single sided 1oz board. Thoughts on this as well would also be much appreciated. I'd prefer the DPAK if I can get away with it.
To answer any questions about airflow, it will be in open air (enclosure has several air vents) but no fan or anything, mounted inside the passenger cabin.
Last edited: