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Help with AD75019

G

guy

Jan 1, 1970
0
Hi all,

I am trying to use the 16x16 analog switch matrix part #AD75019 from
ANALOG DEVICES. I am controlling it using a PIC. The problem is,
regardless of what I put on SIN, SOUT is stuck HI. Is there some sort
of precharge sequence to initialize the connections? this is very
important to my project and I would appriciate any help at all.

Thanks in advance
Guy
 
G

Glenn Gundlach

Jan 1, 1970
0
Hi all,

I am trying to use the 16x16 analog switch matrix part #AD75019 from
ANALOG DEVICES. I am controlling it using a PIC. The problem is,
regardless of what I put on SIN, SOUT is stuck HI. Is there some sort
of precharge sequence to initialize the connections? this is very
important to my project and I would appriciate any help at all.

Thanks in advance
Guy

I've never used this AD chip but looking at the data sheet, the shift
register is dynamic and requires a minimum 20 KHz clock rate. Are you
achieving this rate? Then there is always the possibility of ESD
failure. Have you looked at the SCLK and PCLK pins with a scope to see
what is really there? I don't think using a meter to look at SOUT will
be useful. Just a thought.
GG
 
G

guy

Jan 1, 1970
0
Yea, I've looked at PCLK, SCLK, and SIN, and the data and timing is
correct... unfortunately the switches aren't taking their right
values, and the SOUT is stuck hi.

clock rate is 2MHz, so that's not the problem.

Any other thoughts?

Thanks
Guy
 
G

Glenn Gundlach

Jan 1, 1970
0
Yea, I've looked at PCLK, SCLK, and SIN, and the data and timing is
correct... unfortunately the switches aren't taking their right
values, and the SOUT is stuck hi.

clock rate is 2MHz, so that's not the problem.

Any other thoughts?

Thanks
Guy

Are you really getting a 2MHz clock into the AD? Did you send at least
256 bits so that SOUT becomes active? Did you ping PCLK within 5mS to
transfer into the static latches? Barring chip failures from poor
handling, I've never had an AD chip that did not work as stated.
GG
 
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