I could relax the top end to 40C if needed.=20 -----Original Message----- From: piclist-bounces@mit.edu On Behalf Of Bob Bl= ick Sent: Wednesday, September 12, 2018 10:37 AM To: Microcontroller discussion list - Public. Subject: Re: [EE] Laser diode sources If you run at 25C all the time then you could do that, too. You spec'd -20 to +50C. Most laser diodes have a -10 to +50C operating spec= .. There's no problem running at -20. The real kicker will be threshold current(the current that the laser turns = on). At +50 it will be the same or higher than your maximum operating curre= nt at -20. You could set a current that barely makes the laser operate at h= igh temperatures, but that same current at low temperatures puts out over 5= milliwatts. At best, expect 5 milliwatts at -20 and 0.2 milliwatt at +40C.= At +50C you'll get nothing. And in reality, you'll never get much output at +50C anyway, even with a pr= oper driver, because you are buying cheap diodes and everybody lies. But yo= u'll at least be able to get a milliwatt or so, while keeping below 5 under= any condition. Best regards, Bob ________________________________________ From: piclist-bounces@mit.edu on behalf of David = VanHorn Sent: Wednesday, September 12, 2018 8:05 AM To: Microcontroller discussion list - Public. Subject: Re: [EE] Laser diode sources Many pointers I have opened simply have the laser and a resistor. -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .