Help ID MOSFET driver chip

[Robert Roland]

I want to repair a speed controller for a brushless DC motor. The
MOSFETs are burned out, and so is this little chip, which I believe is
a dual driver for the MOSFETs.

Here's a picture:

http://home.c2i.net/w-479147/temp/driver.jpg

It is marked "IX" or "XI". That does not give me any clue.

Each driver drives two SI4442 and three SI4405 MOSFETs. The speed
controller is controlled by an ATMEGA8.

I have an identical speed controller which is working OK, so I can
take measurements from that if it helps.

I need to find out exactly what part this is, so I can try to find
them or a suitable (pin compatible) replacement.
--
RoRo

 

[Gareth]

On 23/05/2011 21:27, Robert Roland wrote:

I want to repair a speed controller for a brushless DC motor. The
MOSFETs are burned out, and so is this little chip, which I believe is
a dual driver for the MOSFETs.

Here's a picture:

http://home.c2i.net/w-479147/temp/driver.jpg

It is marked "IX" or "XI". That does not give me any clue.

Could it be X1? that returns a few hits here:

http://www.random-science-tools.com/electronics/SMD_markings.php?formtype=SMD_markings_search&search_string=x1

Unfortunately though these markings are not unique and it may not be any
of those.

Each driver drives two SI4442 and three SI4405 MOSFETs. The speed
controller is controlled by an ATMEGA8.

I have an identical speed controller which is working OK, so I can
take measurements from that if it helps.

It may be easier to work out what it is from measurements than the markings.

I need to find out exactly what part this is, so I can try to find
them or a suitable (pin compatible) replacement.

 

[Grant]

On Mon, 23 May 2011 22:27:56 +0200, Robert Roland <fake@ddress.no> wrote:

I want to repair a speed controller for a brushless DC motor. The
MOSFETs are burned out, and so is this little chip, which I believe is
a dual driver for the MOSFETs.

Here's a picture:

http://home.c2i.net/w-479147/temp/driver.jpg

It is marked "IX" or "XI". That does not give me any clue.

Index mark to left, so it's XI? Hmm X1? --> dual transistors pnp + npn
is feasible for emitter follower gate driver?, see

http://www.s-manuals.com/smd/x1

for several options

Each driver drives two SI4442 and three SI4405 MOSFETs. The speed
controller is controlled by an ATMEGA8.

I have an identical speed controller which is working OK, so I can
take measurements from that if it helps.

I need to find out exactly what part this is, so I can try to find
them or a suitable (pin compatible) replacement.

 

[Robert Roland]

On Mon, 23 May 2011 22:23:54 +0100, Gareth <me@privacy.net> wrote:

Could it be X1? that returns a few hits here:

http://www.random-science-tools.com/electronics/SMD_markings.php?formtype=SMD_markings_search&search_string=x1

That looks very promising. A twin transistor could well be used in
this application.

It may be easier to work out what it is from measurements than the markings.

I have now done some measurements. It seems the two transistors are
interconnected somehow, so it is tricky to get some sensible readings.
I have also tried to examine the connections on the board, but that's
not easy, since the board has more than two layers, and uses buried
vias as well. I'm quite sure, though, that one of the bases is
connected through a 4.7k resistor to a pin on the microcontroller.

Thanks Gareth and Grant.
--
RoRo