Mystery PWM chip???

[Don Lancaster]

I have a large quantity of dual H-bridge drivers that apparently
need repair. Working, they should be rather valuable.

The main chips are F540NS MOSFETS that apparenly are driven by IR2104S
drivers.

The key integrated circuit is missing and presumed to be a PWM circuit.

Other clues are that it is a conventional 24 pin narrow DIP and probably
is International Rectifier. SMT construction and probably 3 to 5 years old.

How many candidate chips would meet this possibility?
Part numbers?





--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Don Lancaster]

I have a large quantity of dual H-bridge drivers that apparently
need repair. Working, they should be rather valuable.

The main chips are F540NS MOSFETS that apparenly are driven by IR2104S
drivers.

The key integrated circuit is missing and presumed to be a PWM circuit.

Other clues are that it is a conventional 24 pin narrow DIP and probably
is International Rectifier. SMT construction and probably 3 to 5 years old.

How many candidate chips would meet this possibility?
Part numbers?

Another hint that should narrow down the search significantly.

Ground pins are in the middle of the chip at 6,7,8,17,18,19.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[legg]

Another hint that should narrow down the search significantly.

Ground pins are in the middle of the chip at 6,7,8,17,18,19.

I don't think you're going to find an IR device fitting that bill.
They don't tend to use large pin-count narrow smd packaging, and they
don't make a point of marketing actual controllers - despite the CIC
designation applied to their range of drivers.

At 24 pins, it could be a motor controller from Allegro, with
ground-sensed functions bypassed, a serially addressed driver
controlled by an external intelligence or, get this, a TI-Unitrode
SCSI terminator(?). Unitrode didn't tend to go overboard on the ground
pins, mostly because they knew what they were doing.

As this part is apparently adequately buffered, there would be little
point in including the ground grouping for heatsinking, unless it was
a normally freestanding low voltage power controller, being used for
its logic features alone. I'd scout for stand-alone h-bridge circuits,
or even audio controllers.

RL

 

[Don Lancaster]

I don't have an answer. But this got me thinking: Are there any search
tools online that allow one to fill in details such as known pin
functions, supply voltages, etc.?

The Newark and Mouser et al filters sort of do this, but you have to
know exactly what class of device you are starting with. It also has to
be something they stock and current production.

The Allegro 2919 does seem to be a possible starting point.
Its grounds are 6,7,18, and 19, and a logic ground can be needed on 8
and 17.

Next step would be seeing if the inputs and outputs align. And what else
Allegro has to offer.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com

 

[Don Lancaster]

The Newark and Mouser et al filters sort of do this, but you have to
know exactly what class of device you are starting with. It also has to
be something they stock and current production.

The Allegro 2919 does seem to be a possible starting point.
Its grounds are 6,7,18, and 19, and a logic ground can be needed on 8
and 17.

Next step would be seeing if the inputs and outputs align. And what else
Allegro has to offer.

The Allegro A3992 seems to match six odd ground pins, one odd vcc pin,
and an oscillator input on a narrow DIP24.

Seems by far the best candidate to date.



--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com