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USB hub IC heatup

imranahmed

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I have extension board with USB hub for mobile charging, there is a 8-pin IC model number erased, please let me know which type of IC is and its model or equivalent IC. The IC is heating up and what is the problem in it?
 

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dick_freebird

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Given the inductor adjacent, my money's on a UC3843 or similar
PWM, that makes the 5V supply. Asking 4A (fully loaded, 4 USB
outputs) might make toasty. Overheating @ unloaded maybe says
there's some fault pulling excess power on the board. Which is
it? The part may be the problem, or may be the victim, do some
more poking around?

Look at the pin connections of the inductor, the ground and raw
supply traces from the upstream USB conn, and see if those match
the UC3843. Might also identify the timing elements for further
validation (or its opposite).

Sometimes erasure is not 100.0% complete, and cross-illumination,
wetting the surface, etc. can let you see brand marks that weren't
-completely- obliterated.

If you are willing to dig deeper, the encapsulation of the DIP8
can be removed (a small file, and stop when the first "breakthrough"
on the topside is seen, then cut away the rest with anX-acto to
expose the die; then Google "UC3843 die photo" and look at the
photo hits for matching layouts; bear in mind there may be later
BiCMOS versions, or me-too knockoffs that appear different in the
die details; chase back to the claimed vendor & P/N, from any
eyeball-likely photo search hits.
 

imranahmed

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Given the inductor adjacent, my money's on a UC3843 or similar
PWM, that makes the 5V supply. Asking 4A (fully loaded, 4 USB
outputs) might make toasty. Overheating @ unloaded maybe says
there's some fault pulling excess power on the board. Which is
it? The part may be the problem, or may be the victim, do some
more poking around?

Look at the pin connections of the inductor, the ground and raw
supply traces from the upstream USB conn, and see if those match
the UC3843. Might also identify the timing elements for further
validation (or its opposite).

Sometimes erasure is not 100.0% complete, and cross-illumination,
wetting the surface, etc. can let you see brand marks that weren't
-completely- obliterated.

If you are willing to dig deeper, the encapsulation of the DIP8
can be removed (a small file, and stop when the first "breakthrough"
on the topside is seen, then cut away the rest with anX-acto to
expose the die; then Google "UC3843 die photo" and look at the
photo hits for matching layouts; bear in mind there may be later
BiCMOS versions, or me-too knockoffs that appear different in the
die details; chase back to the claimed vendor & P/N, from any
eyeball-likely photo search hits.
Very descriptive information, I try it and match with UC3843.
 

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