Need a mosfet...What the heck is a Mosfet?

[Bahnzo]

Dan, That makes sense except for one thing. The wire to the atty ground. Is that being taken from any of the chip's drains, or all of them or what? I don't understand where that wire is connected.

Edit: or...is there a big plate on the chip that is basically connected to the drain? Don't have one of these yet, but ordered a few samples from TI.

 

[Scubabatdan]

Dan, That makes sense except for one thing. The wire to the atty ground. Is that being taken from any of the chip's drains, or all of them or what? I don't understand where that wire is connected.

Edit: or...is there a big plate on the chip that is basically connected to the drain? Don't have one of these yet, but ordered a few samples from TI.

You are correct, if you look at the solder foot print in the datasheet
http://focus.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=csd16325q5c&fileType=pdf
the bottom plate is one large solder point for the drain leads.
Dan

 

[Bahnzo]

You are correct, if you look at the solder foot print in the datasheet
http://focus.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=csd16325q5c&fileType=pdf
the bottom plate is one large solder point for the drain leads.
Dan

Got it, thanks! Any idea on delivery time for TI free samples? Beginning to wish I had ordered some more.

 

[Rothman]

Well, there goes that idea.... TI will not ship to APO boxes even though they clearly have Armed forces pacific in their drop down menu.

I guess it's time to seek another avenue...

 

[Scubabatdan]

Got it, thanks! Any idea on delivery time for TI free samples? Beginning to wish I had ordered some more.

Just ordered my 5 free samples, the last ones got here in 4 days.
Dan

 

[Feech]

The 5v regulator with control pin from Madvapes works with 3.7v as a mosfet. I've used it in a few mods where the batteries can be arranged in series or parallel.

 

[Scubabatdan]

Well, there goes that idea.... TI will not ship to APO boxes even though they clearly have Armed forces pacific in their drop down menu.

I guess it's time to seek another avenue...

PM me your addy and I will see what I can do about sending you a couple when they come in.
Dan

The 5v regulator with control pin from Madvapes works with 3.7v as a mosfet. I've used it in a few mods where the batteries can be arranged in series or parallel.

Thanks for the info but that was already covered. The OP wanted the smallest foot print because of space and the madvapes regulator is huge in comparision to the TI chip.
Dan

 

[eHuman]

OK the "what to get" and "how to wire it" questions are adequately being handled.

An attempt to shed light on what a mosfet is doing for you to save your precious little switch: Think of a relay that has say a 12VDC coil (switch) that when activated closes a set of contacts that is used for the main load that completed a 120VAC circuit...

Your mosfet is acting like this relay. Your switch (instead of passing the full voltage and high current that goes to the atty), is passing a nominally smaller voltage and amperage to the "coil" of the relay, (Which is why it will be stepped down). That signal will open a separate path for the higher current needed by the atty to flow.

Caveat: If your switches where failing due to over current/voltage conditions then the mosfet will solve the problem. But if they were mechanical failures due to poor quality devices then to same thing will happen with a mosfet in the circuit.

I doubt this is the case but so you understand the need for quality in this componant vs, "i'll put what fits".

This is the one moving part on your mod and is subject to wear and tear by the most modest of vapers. Make sure it is of decent quality.

 

[eHuman]

Well, there goes that idea.... TI will not ship to APO boxes even though they clearly have Armed forces pacific in their drop down menu.

I guess it's time to seek another avenue...

Ship to your mom/brother/uncle/nephew/friend and have them slap a new label on and APO ship to you. (Did 12 years myself.)

Networking baby!

 

[Rothman]

Dan, you rock!


eHuman, awesome info. That was a really good way of breaking it down. Makes much more sense to me now. Thanks!

 

[Bahnzo]

For smallest size, I would go with the TI chip:
Power MOSFET - Power MOSFET Transistor - CSD16325Q5C - TI.com

Just got my samples today of this chip.......holy sheet these are small. Gonna really test my soldering skills. Looks like it's time to finally buy a Helping Hands...preferably with a magnifying glass I guess.

 

[Whistle_Pig]

Just got my samples today of this chip.......holy sheet these are small. Gonna really test my soldering skills. Looks like it's time to finally buy a Helping Hands...preferably with a magnifying glass I guess.

I finally broke down and bought a Magna Visor. Works great. And you're not dealing with having to reach under an attached magnifying glass to work. I've used one of those soldering clamp things for years -- very handy.

 

[Bubo]

(I finally broke down and stole my wife's reading glasses.. Shhh! Don't tell her!)

 

[Bahnzo]

I finally broke down and bought a Magna Visor. Works great. And you're not dealing with having to reach under an attached magnifying glass to work. I've used one of those soldering clamp things for years -- very handy.

I bought a Helping Hands from HarborFreight.com that has a magnifying glass as a separate attachment, so we'll see how that goes. The visor thing looks expensive.

 

[Whistle_Pig]

I bought a Helping Hands from HarborFreight.com that has a magnifying glass as a separate attachment, so we'll see how that goes. The visor thing looks expensive.

Nope. I don't recall exactly what I paid -- ordered through Amazon -- but if it'd been expensive, I surely wouldn't have bought it.

 

[Bahnzo]

Nope. I don't recall exactly what I paid -- ordered through Amazon -- but if it'd been expensive, I surely wouldn't have bought it.

I found it online for $40, so not bad, certainly less than I thought it might be. Still more than I want to pay right now..if the magnifying glass don't work, then it might look cheaper to me.

 

[Madshock]

Does the ti mosfet work for 5v?

 

[Rothman]

Nope. I don't recall exactly what I paid -- ordered through Amazon -- but if it'd been expensive, I surely wouldn't have bought it.

Ahh.. a man like myself. If it's not cheap, I don't own it. My wife hates it....

 

[DaveP]

Go to Harbor Freight, Northern Tools and buy a set of magnifying goggles. They flip up and down like a jewelers loupe and give you a couple of close up hands free views of your work.

Clean up your soldering iron tip to expose the copper, tin that area, and wrap the wire from a paper clip tightly around the tip. You need several wraps. Leave about 1/3" to 1/2" protruding past the tip to act as your "new" tiny soldering tip.

Using the handsfree magnifier and the tiny tip, you can solder these circuits with ease! Now, you need to work on shaky hands ...

 

[DaveP]

Sorry, double post. Board is a little creaky today.