Thanks everyone. It's not really the answer I wanted to hear though. I'm running the Protoboard at 6V and feeding Vin to the servo circuitry. I'm actually powering two monaural amplifiers from this using a TBA2002 (or something like that) rated at 8W peak (at 12V or so). I think they're rated at 2-3W peak at 6V which is probably enough for my needs. With two amps and a realistic efficiency, I'm well over the inductor rating at high volume levels. I think the average sound levels are low enough to manage.
For Parallax: It doesn't make sense to use an inductor rated at 400ma in a circuit that, even with only one servo, can easily see peak currents in excess of 1A. With 4 servo headers, it's easy to go way beyond that and yet be within a reasonable current demand for Vin. How about beefing up the inductor or providing an easier way to add a higher power inductor in its place?
No we specified Murata LQH32CN1R0M53 which is a 1 ampere part, however now that I am looking at the board and datasheet I can see a substitution was made. I will test the component and see if it will handle the specified current, if not those who need the extra ampacity can substitute the component on thier board since the Murata part is pad compatible.
I've just tested the part at 1 A, the case temperature steady states at 48 C (120 F) in 33 C ambient (yes my lab is presently 92 F) and seems perfectly capable of sustaining that current. When it was cranked up to 2 amps, the case temp reached 127 C (260 F) and failed after approximately 30-45 seconds.
Comments
My guess is that it's a Bourns PM1210-1R0J rated at 400mA...
1uH/0.7 Ohm/400mA
http://www.mouser.com/search/refine.aspx?Ntt=810-NLV32T-1R0J
Franz
For Parallax: It doesn't make sense to use an inductor rated at 400ma in a circuit that, even with only one servo, can easily see peak currents in excess of 1A. With 4 servo headers, it's easy to go way beyond that and yet be within a reasonable current demand for Vin. How about beefing up the inductor or providing an easier way to add a higher power inductor in its place?
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Paul Baker
Propeller Applications Engineer
Parallax, Inc.
Post Edited (Paul Baker (Parallax)) : 8/28/2007 10:35:40 PM GMT
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Paul Baker
Propeller Applications Engineer
Parallax, Inc.