[TVaudio]

I kinda blew something up on my EB01 DAC when I was replacing some caps.
I don't know what is, but it says FA51 on it.
I have included a pic. It is at position U5

 

[splaz]

Well my guess is. Voltage regulator of some description.

Given it's a DAC, I'm presuming something like 3.3 or 5V.

 

[threepointone]

you're probably going to have to figure out the schematic to get an idea of what it is--it's not going to be easy to figure out what a 4 character smt marking means. if you're really unlucky, it might just be a date code.

and um--is that a blob of solder or is that the casing blown open in that pic? are you sure it's fa51, because the first character looks a bit like an N from this picture. And don't forget to fix whatever ended up blowing the IC, or you'll just blow the next one you get.

 

[TVaudio]

It's definitely an F. I took a look under a magnifying glass.
What caused the problem was dummy me cooked it with my soldering iron by accident.

 

[beerguy0]

It's not a National or Linear Technology part. They both have package code to device cross references, and FA51 does not show up on either list. Unfortunately, other vendors don't provide such information, at least not where I could find it.

You may have to trace the circuit out, to get an idea of what it might be. In your picture, pin 1 is the lower left corner, and the numbers go CCW around the chip. For a positive regulator in this package, pin 1 is usually Vin, Pin 2 is ground, and pin 5 is Vout. Pin three is usually an On/Off pin, and pin 4 is a bypass pin for low noise output.

Edit: Looking at the photo more closely, I'm not so sure that it is a voltage regulator. The inductor (L4) in the photo is between pin 1 and pin 5. If it were a voltage regulator, this would be tying Vin and Vout together, since inductors are a DC short.

 

[TVaudio]

Thanks for everyones input. I'm not sure what I'm going to do about this. I can't find a reference to this part either. I may be looking for a new DAC.

 

[Pars]

You could always ask the manufacturer for a schematic, or at least have them supply you with the specs for the part...

 

[achina]

I think this is it:
AP1522W DC-DC converter SOT25 package
http://www.diodes.com/datasheets/dsAP1522.pdf

According to the datasheet it should be FA5I. FA for the chip identifier and 5 for 2005 and I for September.

The schematic fits what I can see of the board layout.

Finding one will probably be difficult. There are probably many very similar parts out there that can be substituted.

 

[TVaudio]

I have emailed requesting info, but I'm not sure if the regular tech support guys can help.

 

[achina]

They list the LM2704 as an equivalent in their cross reference.
http://www.diodes.com/products/cross...ndex_pwm_l.php

Digikey has them in stock.
http://www.digikey.com/scripts/DkSea...697347&Site=US

 

[TVaudio]

achina thats awesome! How did you recognize this part? I may yet still be able to save this DAC.

Thanks again

 

[threepointone]

wow--do you have some secret SMD part search database or something? that's crazy

Might want to double check that the circuit matches the specified schematic--I'd be rather uneasy assuming that a two letter match means it's the exact right part

 

[achina]

Quote:

Originally Posted by threepointone /img/forum/go_quote.gif wow--do you have some secret SMD part search database or something? that's crazy

Did a search in google for "fa51 sot" It was listed in the first hit. Luckily whoever cataloged the part put a 1 instead of an I.

Quote:

Might want to double check that the circuit matches the specified schematic--I'd be rather uneasy assuming that a two letter match means it's the exact right part

Yes, definitely follow the circuit and see if it follows the app notes in the datasheet. The 2704 has a lower max input voltage. I think this thing is USB bus powered so that should not be a problem. If it is a AP1522W then you can figure out the output voltage by identifying the R1 and R2 (in the figure on page 3 of the datasheet.)

 

[achina]

100K is a common marking for a 10uH inductor. 10 and a 0 multiplier. Sort of like resistor codes but only 3 digits. K is 10% tolerance. So that would fit the schematic.