Diodes is lately a lot more than diodes. A similar case is Onsemi, a spinoff of Motorola that inherited the cheap gumdrop business but does a lot more now.
Diodes has some dynamite new switchers, the AP66200 parts, that I'd like to use.
Any experience with Diodes, as regards support and especially keeping parts in production? Any horror stories?
We’ve had good luck with them. Some of their analog parts are odd, both for good or ill.
Their TLV431 is better than TI’s original, and much much better than the onsemi version.
Their TLC271 is, like, 30 dB noisier than TI’s.
Haven’t used any of their switcher parts.
Cheers
Phil Hobbs
That switcher looks fabulous. I'm designing a board with maybe 125
12-volt-coil relays and I have to switch +48 down to 12 and have about no room to do it in. HV-input switchers are rare. I like the old LM2576HV-ADJ but it, and its inductor and caps, are gigantic.
I use these only as overvoltage detecting refs for a 1.5V supply so I have not noticed which are better, in fact I don't know which ones we have been using. Thanks, good to know.
I am eyeing their AP62800, rated at 8A and I need sort of 6. However their diagrams are only (mostly) at 5 and 3.3V out, I want to use it at 1V (where the 6A will be, may be elsewhere as well. Meaning I'll have to test it before committing, stability, (huge) load change response etc. can take me by surprise.
And thanks to John Larkin for mentioning diodes as a source.
How many of them are switched on at the same time? How do you deal with the initial surge? I am looking for a way to have a short delay to sequence on 24V relay coils.
Do you have a spare contact on each relay?
No, all used on DPDT.
I hve used Diodes Inc for many many years.
Good stuff as I remember.
boB
They do make good parts and, most of all, at good prices.
Yep, one. I designed a specialty circuit around their AP63200. Worked beautifully until ... the AP63200 became hardcore unobtanium. Many manufacturers had such supply chain problems though so I am not going to diss them for that. Heck, for a while you couldn't even get toilet paper around here.
Subsequently I did the usual, designed it back out and made the whole circuit jelly-bean and discretes so there would no longer be much of a supply chain risk. Now this client has two designs, a fancy nice one and a more mundane fallback version if things hit the fan. A good insurance policy on their part.
Long story, over the last few years I really got weaned off super nice parts and rather go a more classic route with less supply chain risk.
Rough guess, maybe 50 max on at once. What surge do you expect?
One trick is to bump up the coil bus voltage to 12 for a while whenever any relay state is changed, and drop it down to the guaranteed holding voltage after a short while. But my relays will only need maybe 200 mW coil power each, under an amp for all 50 on, so that's not worth the hassle here.
I'm thinking of using an Efinix FPGA and ULN2003s as the coil drivers.
I could plop a few pcb test points around the part. If I can't get it, I could make a little baby board regulator and stand it off the main board on a few wires.
The supply situation is less crazy now, and some people have garages full of toilet paper.
torsdag den 20. juli 2023 kl. 01.16.45 UTC+2 skrev John Larkin:
this would save routing,
My relays draw 80mA @ 24V, or close to 2W to hold. A 3.7V to 24V booster can only start two of them at the same time. I might need bigger booster, unless I can sequence the starting.
We use that part in some other places. But it's physically big and they would actually cost a tad more than the fpga+uln drivers. I can squeeze the ULN2003s on the bottom, between the relay pins.
Diodes Inc does the ULN2003 too.
A single mosfet under each relay would be cool, but I'd need a catch diode or an avalanche-rated part.
OK, 2 watts per coil, 10x mine. And I have a kilowatt of +48 supply available.
48v relays would be great, but the 12 volt ones are a lot easier to get. Automotive stuff.torsdag den 20. juli 2023 kl. 02.53.23 UTC+2 skrev John Larkin:
On 2023-07-20 02:38, Eddy Lee wrote: [...]
What do you think the current vs. time curve of a relay pulling in looks like? It's probably not what you think.
Jeroen Belleman
The inverter can handle 3A (I assume it's input current) or 25W. The relay draws 600mA @ 3.7V input and 80mA @24V output. It should be able to hold 5 relays, but only able to start 2.
Correction:
That's wonderful. The distributor search engines don't show avalanche as a feature so I've been opening and reading scores of PDF data sheets. I need a components reasearch engineer; I spend too much time prowling for parts.
We could do a dual footprint, or just put two fets under each relay, so we could buy that package or a SOT-23.
Another idea is to use a high-voltage fet and ensure that the flyback spike never hits the breakdown voltage. Relay coils are not very high-Q inductors.
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