Is it possible to replace SY8009 voltage regulator IC with AMS1117 ⁉️✍️

electronium

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greeting to the colleagues of the forum
As an electronic repair, they bring me set-top boxes, receivers, modems, TVs, etc. for repair. Interestingly, there is a common point between all these devices that the IC regulator of the 5v and 3.3v 2.5v 1.8v 1.2v power supply section burns. Is it possible to use the 1117 constant voltage regulator for the ease of work and the lack of time and energy spent to check the datasheet of the 6-pin or 5-pin IC?


 
Last edited:
No.

The SY8009 is a switch mode voltage converter whereas the AMS1117 is a linear regulator. Not the same thing.

https://www.olimex.com/Products/Breadboarding/BB-PWR-8009/resources/SY8009.pdf
 
If you knew the (Vin-Vout)*Iout= Pdiss was less than say 0.6W which causes a Tjcn rise of 160*0.6= 96'C above ambient it might work. But for example (5-3.3V)*1A= 1.7W (66% efficient).

It sounds like OEMs are underdesigning the copper heatsink needed for the rate losses and they are overheating into a thermal runaway condition after a while. FETs have a PTC parameter.
 
aliarifat794 said:
The pinouts also look different to me.
Click to expand...
I know the output pins, I wanted to replace the board with three pins from the main input and output pins or the IC auxiliary board. If this trick is implemented, my work will be easier because some ICs are not available in our country and market
 
I'm not sure exactly what trick you are talking about. If you can't get the chips that were designed into the product, then you have little to no hope of repairing them. Just because someone brings you something to repair does not mean you are obligated to jump through impossible hoops. You need to accept that some things are beyond your control, and you need to learn how to communicate that as diplomatically as possible.

OTOH, you could propose a first-class roundtrip plane ticket to the country of your choice along with a couple of days at a 5-star hotel for you to obtain the required parts. The CFO might balk at the expense, but the user of the equipment might be over the moon.
 
There is a digital receiver board (setup box), the IC regulator part of the main board is 3.3v and 1.2v burnt, the 5-pin IC regulator is not available, so I have to consider a constant voltage regulator for it and take the work to the customer.

 
As has already been pointed out, the original board was designed with a switching regulator. They must have made that choice for a reason. You would be risking a great deal by replacing the switching regulator function with a linear regulator. Are you sure it will survive in the enclosure over a range of ambient temperatures. If I was your supervisor and you brought this idea to me, I would reject it out of hand as unworkable. If you customer would be unhappy then tough rocks.
 
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