After having Marcos review the BOM as is lies today:
(12:44:low Z AbeFM?
(12:59:no atm pressure?
(1:09:you have something like a hall sensor, so you don't need the MAX9924?
(1:10:The BOM seems good to me
(1:16:order some extra 33v zeners, but in a smaller package
(1:18:but I guess you're going to use it in the default linear mode
(1:19:so no need to have a 5W znere in there
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My thoughts: We need to get it right and understand it first, you can't have a webpage which autogenerates crap.
With any luck, we should be in a position for it in the next day or two, though.
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More comments:
1) MOSFETs unavailable, looking for suitable replacements
http://search.digikey.com/scripts/DkSea ... P30N06L-ND
$1.02, 60V, 32A, 35mOhm
http://search.digikey.com/scripts/DkSea ... P50N06L-ND
$1.25, 60V, 50A, 21mOhm
To my mind, 32 amps is plenty, and while I like the lower resistance, we're only talking 500mW verses 700.... Well, ok, let's spend the 20 cents. Of course, at 2 amps (more likely for a fuel pump, honestly 1 amp is more like it) it's only 50 mW. I hope the pin-out works.
2) EGT
I found this:
http://search.digikey.com/scripts/DkSea ... 96-8009-ND 12V LDO (already posted) but I don't know if 150 mA is enough
Turns out Marcos likes it, so I'm going with it. Only costs 68 cents, the bigger cost (by far!) is the EGT readout chip itself.
AD8497ARMZ-ND is the IC itself, only $5.
3) MAP
http://search.digikey.com/scripts/DkSea ... 300AC6U-ND
This is smaller, cheaper, and supports a sensible boost level for I-4's. $9.99 and does 2.85 bar (27 psi) verses the 2.5 bar (i.e. 21 psi). Different footprint, but you're at least getting a range that you won't run out of until you really get silly with the boost.
The "normal" MS sensor (MPX4250AP-ND) would actually be my choice for baro. Even though you can use: (MPX4100A-ND)
http://search.digikey.com/scripts/DkSea ... ND&x=0&y=0
there are two issues: One, it only reads vacuum, and do you really need that extra accuracy? And two: No port! Sometimes you just want to do logging. I'd actually be pretty tempted to put on one of the differential parts - awesome for monitoring drop across intercooler or throttle plate. You could even use it for your exhaust system. With a long, carefully done pipe, you could probably measure drop across your turbo and/or wastegate.
http://dkc3.digikey.com/PDF/US2011/P2748.pdf for some ideas.
4) USB port
What is a good/the best USB port to use?
http://search.digikey.com/scripts/DkSea ... ND&x=0&y=0 is on the BOM but I think this is changed??
4b) USB Cable
http://search.digikey.com/scripts/DkSea ... ND&x=0&y=0 probably also isn't needed.
not-here-1) While I don't need VR, I might go to it someday. Anyway, for the sake of completeness:
MAX9924UAUB 1 x Differential 1V/V
MAX9925AUB 1 x Operational Externally Set
MAX9926UAEE 2 x Differential 1V/V
MAX9927AEE 2 x Operational Externally Se
Why WOULDN'T we use the MAX9926, which supports two channels?? $3.77 verses $2.60 for the stand alone.
As for me, it's op-amp city, it works so bleedin' well, there's no reason not to. At least, I think it works well, plus it's what Mazda ships from the factory, so they can't be too bad.
not-here-2) Low-Z injector Controllers
http://www.infineon.com/dgdl/TLE6270_DS ... 20e4701141
OMG I love this chip. Unless I'm missing something. I guess this doesn't really belong in the BOM section. Same for the one above it.
2.3A hold current, fine for anything low or high z. 0.3 ohm is a little high, but not a killer.
5) XOR gate, shortage of parts?
MC74HC86ADR2GOSCT-ND - the XOR gates, there are very few of these in stock, not sure what to do about it. At least they are cheap.
6) Peak and Hold Zeners:
From the comment at the start of the post 1N5364BRLGOSCT (5W Zener) isn't needed. But I'm not sure what footprint I want, or what size.
http://search.digikey.com/scripts/DkSea ... ENER%2033V will help me find it, but I'm at a loss. What IS a good size?
7) P&H Darlington
I'm not sure why I took this off my list:
http://search.digikey.com/scripts/DkSea ... ND&x=0&y=0
I guess I'm not sure what the circuit looks like. I probably removed it because I already own some, but, for clarification, are these still the best part to use?
8) Fuse Block
http://search.digikey.com/scripts/DkSea ... ND&x=0&y=0
I heard we're not using these? I guess I'm neither for not against it. It really shouldn't be needed, then again, it won't hurt anything. I'd probably rather see a blade fuse like the rest of the car uses, no? They are pretty standard and you can get it anyway, you could also solder one in on leads, available at any FLAPS
9) Stepper Motor Driver
I keep forgetting some cars have these. Seems silly to me.
620-1158-1-ND The point is, the part is discontinued so if you need this act now!
If you don't, don't buy it, it's pricey!