Help identifying VRM (SOT-223)

[y_not]

I found this VRM on a router board. I have no idea what it's voltage is because I can't identify it. Appears to be a Chinese knock-off.

There are 2 differently marked ICs of this package type on the board. Marked: ADB320 & ADE317.
It appears that the top, large leg is indeed the ground.
On the R. most leg, with the 3 legs facing you and the ground tab facing away.
VRM at PSU jack = 5v out
VRM at LEDs (Black round things in photo) = 3.3v outC

Could the ADE317 just be an equivalent to a TI LM317?

I'm not sure which is in & which is sense/adj. of the other 2.
I think the center leg might also be ground.


If you could kindly check out the pics and let me know your ideas/thoughts, that'd be great!!

Thx.

[budm]

Re: Help identifying VRM (SOT-223)

LM317 is an adjustable regulator, the center pin (which is tied to the big tab on top) will not be at ground, so it is not LM317.
The left pin is an input pin, which also indicated on the silk screen as 5V, the output pin is the right pin. What do you get on that right pin?

[y_not]

Re: Help identifying VRM (SOT-223)

LM317 is an adjustable regulator, the center pin (which is tied to the big tab on top) will not be at ground, so it is not LM317.
The left pin is an input pin, which also indicated on the silk screen as 5V, the output pin is the right pin. What do you get on that right pin?

See my attachment with notes.
I didn't really write any notes down as to the resistance measurements I made. But from memory, which is usually darn close, if not spot on, I have noted the values where applicable.
I will add that the right pin, 5v out, showed about the same resistance as the center pin I noted.
Lastly, my readings were all approx. as I wasn't shooting for pinpoint accuracy.

I'm going to be repairing, maybe, the AC/DC transformer for this unit, as it has some horrid caps in it. Since the psu is 5v DC out, I was just trying to figure out if a 7.5v power brick from another model in the same line would work. It actually reads as approx 11.5v, which it climbs up to from about 11/11.25v as I keep the leads on it. But I know that brick is good, nothing wrong with it.

I read that voltage tolerance is determined by the VRM being used, often on newer equipment they'll take a higher voltage. So I was trying to figure out what this silly no-name VRM is.
I'll also add that the next HW revision up from this one, which is v1, so v2, shipped /w a 12v PSU and uses the same PCB. But I can't find any internal photos of the newer version.
Lastly, this is a Netgear WGT624v1 wireless router if anyone is curious or it's relevant.

[budm]

Re: Help identifying VRM (SOT-223)

In your pictures, that center pin looks like it has 3 caps connected to it, I can see C45, another one I cannot read, and the third one looks like it is blocked out by white paper?
Regarding to the AC adapter, the 5V one, is it regulated 5V power supply (more likely to be switching power supply). The 7.5V power supply is more likely to be linear unregulated power supply type which will show much higher voltage when is not loaded at the rated current, I.E. it may have labeled as 7.5vdc @1A, which mean it will put out 7.5V when the load is drawing current of 1 A, if less than 1A current is drawn, the output will be higher than 7.5V as you find out.
So look at the original power supply to see what kind it is. I would not use that 7.5V power supply since it will stress out the regulator.
That center pin may be the ON/OFF control pin.

[waqqas.qayyum1]

Re: Help identifying VRM (SOT-223)

Hi Guys,

I am going to use lm317 sot223 for one of my project. I need to get information regarding the pins. One is Vin, 2nd Vout, 3rd Vadj and 4th one i need to know that it would be connected with ground or what?

[dskall]

Re: Help identifying VRM (SOT-223)

I would say pin 1 is adj. Pin 2 is out Pin 3 is input and 4 or tab is tied to pin 2

[budm]

Re: Help identifying VRM (SOT-223)

https://cdn.badcaps-static.com/pdfs/...939abd1e5b.pdf
There is direct GND connection for the Adjustable type.
Look at the math on how to use the two resistors to set your output Voltage and the require Minimum input Voltage for the required output.