On 28/04/2011 11:12 AM, Dave Tweed wrote: > David Duffy (AVD) wrote: >> I have a product that would normally be used with a DC input of 12V - >> 36V. It uses an LM2575 switching regulator to derive the 5V rail (@ few >> 100 mA) for a PIC and other chips. >> >> The lowest of the maximum Vdd ratings on these chips is 6V. There is a >> situation where some customers may need to power the board from 5V. >> >> I can provide jumpers to bypass the regulator section, but would like to >> protect the 5V chips from accidental connection of a higher voltage >> while still jumpered for 5V. >> >> Looking at transorbs and zeners (with a series fuse or polyswitch) gives >> me the impression that they will not save the logic chips being >> toasted. Any ideas? > I was just researching this myself today. Linear Technology makes some ni= ce > power-management chips. For your application, you might take a look at th= e > LTC4365, which provides undervolta= ge, > overvoltage and reverse-voltage lockout with low overhead. > > For my own application, I'm looking at the LT4356 to provide additional > robustness when my system is powered from 12V or 24V vehicle power buses. > > I already use the LTC4210 hot-swap controller as a software-controlled sw= itch > and overcurrent protector to manage peripheral loads in one of my systems= .. Hi Dave, That looks interesting. Will see if it fits in the budget. David... --=20 ___________________________________________ David Duffy Audio Visual Devices P/L Unit 8, 10 Hook St, Capalaba 4157 Australia Ph: +61 7 38235717 Fax: +61 7 38234717 Our Web Site: www.audiovisualdevices.com.au ___________________________________________ --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .