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Low Dropout Regulator replacement? (Newbie)

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vwtoys

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I'm diagnosing a CCD security camara made by Toshiba. It was used and sold to me through Ebay. It was DOA and when compared to an identical working unit I found that the LDO is burnt. I confirmed it was not outputting any voltage. So here's my dilemma...

burnt LDO PN RT6193 50CG3BR1:
It's a RichTech RT9163, SOT 223 Type I I think, spec sheet here.
https://www.electro-tech-online.com/custompdfs/2010/09/rt916350cgl.pdf

I don't think I found any exact replacement parts. So I'm out looking for an equivalent. So I found something like this on ebay:
**broken link removed**

Question is, will it work? The output pins might be switched. I guess I could solder wires to the board instead.

Any other suggestions? Any leads to a better replacement? Thanks!!
 
I'm diagnosing a CCD security camara made by Toshiba. It was used and sold to me through Ebay. It was DOA and when compared to an identical working unit I found that the LDO is burnt. I confirmed it was not outputting any voltage. So here's my dilemma...

burnt LDO PN RT6193 50CG3BR1:
It's a RichTech RT9163, SOT 223 Type I I think, spec sheet here.
https://www.electro-tech-online.com/custompdfs/2010/09/rt916350cgl-1.pdf

I don't think I found any exact replacement parts. So I'm out looking for an equivalent. So I found something like this on ebay:
**broken link removed**

Question is, will it work? The output pins might be switched. I guess I could solder wires to the board instead.

Any other suggestions? Any leads to a better replacement? Thanks!!
you might consider LM2931 in TO92A package and it can delivcer 100mA load.
there could be many others like
TLV1117-50
LM2937IMPX-5.0
LT1763CS8
BD3574HFP
 
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I recommend the Micrel MIC5209-5.0YS. The pinout is reversed, as with most SOT223 parts, but you can easily mount it upside down by carefully bending the leads to form towards the top surface rather than bottom surface of the component. It is important to get the large tab well soldered to the copper on the board with lots of metal contact (blob the solder if you must) for good thermal contact.

I do not like the AMS1117 for two reasons. One is that it is harder to mount. The second is that it is less stable, requiring a 22uF tantalum on its output. The Micrel part will be fine with your existing 10uF electrolytic on its output.
 
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Thanks for the tips. I'll look up the Micrel parts as well.

There are other bad units in the batch, these cams all take either a 12VDC or 24VAC input on the power circuit board. This feeds the camera board with the voltages necessary to run the CCD and the Auto Iris lenses I'm assuming.
On the good unit the input side it's 5.87v and output side is 4.75v. On another bad unit there's 6v on the input side, and 0v coming out of the output. So I guess the LDO on that unit is dead as well. I think there's a transformer in front of the LDO that takes the 12VDC input down to about 6v then the regulator trims it down to 5v? I'm also seeing some units with bulging caps, not leaking yet. I think I might have to replace all those caps too?
 
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Thanks for the tips. I'll look up the Micrel parts as well.

There are other bad units in the batch, these cams all take either a 12VDC or 24VAC input on the power circuit board. This feeds the camera board with the voltages necessary to run the CCD and the Auto Iris lenses I'm assuming.
On the good unit the input side it's 5.87v and output side is 4.75v. On another bad unit there's 6v on the input side, and 0v coming out of the output. So I guess the LDO on that unit is dead as well. I think there's a transformer in front of the LDO that takes the 12VDC input down to about 6v then the regulator trims it down to 5v? I'm also seeing some units with bulging caps, not leaking yet. I think I might have to replace all those caps too?

The original LDO has a dropout voltage spec that is larger than the ones we use now. That implies that a good input voltage should be higher than 6.5VDC to give a clean 5V output. That good unit may have an intact 5V regulator but is not getting enough voltage at its input, it seems.
 
Hi Radio Ron, thanks for the reply. I haven't got a clue in electronics as I'm a mechanical engineer by trade. So are these CCTV camera modules (Toshiba from 8 years ago) supposed to be 5V standard? I'm guessing you're implying that the bulging caps might be limiting the supply voltage to the regulator? Is replacing the caps a good first step to bring these things back to life?
What causes the LDO to burn out or die? Would bad caps cause it? I'm guessing these caps are the bad batch that was being manufactured in the good old days with bad/counterfeit caps killing motherboards and other electronics?
 
You might try other LDO voltage regulators. I have a KA78R05 ( TO-220, DO < 0.5V), LT1086CT ( TO-220, DO < 0.3V), and an L1084 ( TO-263, 5A max, DO 1.2V). I'll try them to see what I get for my circuits.
 
Hi Radio Ron, thanks for the reply. I haven't got a clue in electronics as I'm a mechanical engineer by trade. So are these CCTV camera modules (Toshiba from 8 years ago) supposed to be 5V standard? I'm guessing you're implying that the bulging caps might be limiting the supply voltage to the regulator? Is replacing the caps a good first step to bring these things back to life?
What causes the LDO to burn out or die? Would bad caps cause it? I'm guessing these caps are the bad batch that was being manufactured in the good old days with bad/counterfeit caps killing motherboards and other electronics?

I was not implying that the bulging caps might be limiting voltage, but you have hit on something there and if the caps are bad that could be dragging down the input voltage a bit. Yes, replacing the caps is a good idea, as they are cheap and easy to replace and bulging is indeed a bad sign.

I must say that in all my years I have rarely had an LDO die. They are typically very robust, with internal automatic thermal shutdown, many with reverse voltage protection and other transient protections. But it can happen, but be suspicious of other possibilities. The regulator that has zero output, is it running hot? If so, then perhaps it has a short circuit loading its output, forcing it into thermal shutdown, and is not actually burned out. The one you mentioned with the 4.75V output doesn't sound broken to me, merely that it is starved of input voltage.
 
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