what are these 8pin smd parts - serial interface

[Grant]

Hi there,

Got a blown serial interface board, and I'm trying to find what are
the two 8pin chips on one side of the PCB, pictured here:

http://grrr.id.au/image/mystery-serial-interface-chips.jpg

One chips has 452, 307 on two lines, the other has 300, 348 on two
lines.

I've read that the top number is last three digits of part number,
and the bottom number is YWW date code, it's reasonable that both
chips were made in 2003.

The SMD code site mentioned recently skips both numbers

Top of photo shows the nine pin serial connector, there's a couple
diodes, some resistors and a transistor on the board, other side of
board has some more components and a 5V regulator. Board is powered
from single supply with one wire for signaling, I have no further
idea how it works -> black box (some sort of motor controller) to
serial port.

TIA,
Grant.

 

[Mike Harrison]

Hi there,

Got a blown serial interface board, and I'm trying to find what are
the two 8pin chips on one side of the PCB, pictured here:

http://grrr.id.au/image/mystery-serial-interface-chips.jpg

One chips has 452, 307 on two lines, the other has 300, 348 on two
lines.

I've read that the top number is last three digits of part number,
and the bottom number is YWW date code, it's reasonable that both
chips were made in 2003.

The SMD code site mentioned recently skips both numbers

Top of photo shows the nine pin serial connector, there's a couple
diodes, some resistors and a transistor on the board, other side of
board has some more components and a 5V regulator. Board is powered
from single supply with one wire for signaling, I have no further
idea how it works -> black box (some sort of motor controller) to
serial port.

TIA,
Grant.

They look rather thick, so may be optoisolators.

 

[Rich Webb]

Hi there,

Got a blown serial interface board, and I'm trying to find what are
the two 8pin chips on one side of the PCB, pictured here:

http://grrr.id.au/image/mystery-serial-interface-chips.jpg

One chips has 452, 307 on two lines, the other has 300, 348 on two
lines.

I've read that the top number is last three digits of part number,
and the bottom number is YWW date code, it's reasonable that both
chips were made in 2003.

The SMD code site mentioned recently skips both numbers

Top of photo shows the nine pin serial connector, there's a couple
diodes, some resistors and a transistor on the board, other side of
board has some more components and a 5V regulator. Board is powered
from single supply with one wire for signaling, I have no further
idea how it works -> black box (some sort of motor controller) to
serial port.

I'd guess an HCPL-0452 optocoupler for one. The connections seem to
match with the inputs and NC pins, and the Vcc/Gnd seem to make sense
with the 200/330 ohm voltage divider if there's a 5 V supply. Serial
input isolator and level translator?

The "300" is most likely from the same manufacturer, what with the
similar marking placement and style, but given the ubiquitous 300 thou
pitch form factor, there are a cubic butt-ton of parts ending in 300.

 

[Grant]

They look rather thick, so may be optoisolators.

Yes, my first thought, but the traces don't follow pattern for the
8pin optos I checked. Tried dual transistor out, and dual hi-speed
with Vcc and Gnd on output (pins 5 - 8) side.

Grant.

 

[Grant]

I'd guess an HCPL-0452 optocoupler for one. The connections seem to
match with the inputs and NC pins, and the Vcc/Gnd seem to make sense
with the 200/330 ohm voltage divider if there's a 5 V supply. Serial
input isolator and level translator?

Thanks! Yep, just checked the datasheet, looks very likely

Yes, it's a 5V supply, a blown 78L05 is on other side of PCB.

The "300" is most likely from the same manufacturer, what with the
similar marking placement and style, but given the ubiquitous 300 thou
pitch form factor, there are a cubic butt-ton of parts ending in 300.

That's the problem I had, sites I searched refused to do a proper *300
search and returned all sorts of unrelated stuff. Maybe now I can narrow
down to the two manufacturers I found with a datasheet, Fairchild and
Agilent.

Thanks,
Grant.

 

[Grant]

I'd guess an HCPL-0452 optocoupler for one. The connections seem to
match with the inputs and NC pins, and the Vcc/Gnd seem to make sense
with the 200/330 ohm voltage divider if there's a 5 V supply. Serial
input isolator and level translator?

The "300" is most likely from the same manufacturer, what with the
similar marking placement and style, but given the ubiquitous 300 thou
pitch form factor, there are a cubic butt-ton of parts ending in 300.

HCPL-0300 or HCPL-2300 seems likely? Low input current opto-coupler.

Another couple views:

http://grrr.id.au/image/mystery-serial-interface-chips2.jpg
http://grrr.id.au/image/mystery-serial-interface-chips3.jpg

Grant.

 

[Rich Webb]

That's the problem I had, sites I searched refused to do a proper *300
search and returned all sorts of unrelated stuff. Maybe now I can narrow
down to the two manufacturers I found with a datasheet, Fairchild and
Agilent.

Perhaps an HCPL-3000, which is motor controller interface/driver and so
it matches with the application. Hard to tell from the picture, though.
In that shot, it looks like pin 7 (which would be Gnd) is floating, so
maybe not.

 

[Rich Webb]

HCPL-0300 or HCPL-2300 seems likely? Low input current opto-coupler.

Another couple views:

http://grrr.id.au/image/mystery-serial-interface-chips2.jpg
http://grrr.id.au/image/mystery-serial-interface-chips3.jpg

Yep, that seems to match the footprint. Pin 7 on the HCPL-x300 has an
internal pull-up so leaving it NC on the board would fit.

 

[Grant]

Yep, that seems to match the footprint. Pin 7 on the HCPL-x300 has an
internal pull-up so leaving it NC on the board would fit.

Thanks for checking the footprints. Really appreciate it

When I repair the thing I'll add some protective components so
withstands the abuse that busted it this time.

Grant.