Looking for Dig-Pots: MAX5402EUA

[Declan Hughes]

Hello,

I am looking for a few (4->10) 256 step linear digital pots in small
packages such as the MAX5402 (8uMAX). These are scheduled to ship from Maxim
in February/12/2004. Does anyone know of an alternative source for 4 -> 10 of
them ?

Thank you,

Declan Hughes
dhughes@aero.tamu.edu

 

[Walter Harley]

"Declan Hughes" <dhughes@abcaero.tamu.edu> wrote in message
news:br7dsn$391$1@news.tamu.edu...

Hello,

I am looking for a few (4->10) 256 step linear digital pots in small
packages such as the MAX5402 (8uMAX). These are scheduled to ship from
Maxim
in February/12/2004.

This seems to be what everyone says about using parts from Maxim...
availability is poor.

Considered an alternate manufacturer?

 

[Declan Hughes]

Yes, I looked at Winbond, Catalyst Semiconductor, Analog Devices, Xicor and
Microchip as well as Maxim. I need to pass an FSK 1.1 or 1.3 MHz sinusoidal
signal through this pot. into the +input terminal of an op-amp, and the ideal
digipot would have >=256 logarithmic steps. The dynamic specs. for these
devices are typically sparse, however the MAX5402 datasheet states the
"Wiper-Settling Time ts To 50% of final value from code 0 to code 128 = 100
ns". The MAX5402 has 256 steps and no output buffer (which might further
constrict its frequency response). I also want a small package, <= SOIC8 .

The CAT5116RI has only 100 steps, however they are logarithmic (which
is good). It has a frequency response of 1.7 MHz when operated as a passive
attenuator at 10 kohm (full R is 32k). This is a new part and I could not find
a source with stock in their list of distributors. I called their Houston
office today and they will see if they can get samples.

In the worst case the prototype will go ahead without the variable intensity
feature, and this will be added Feb/2004 when the Maxim parts arrive
(hopefully). I am also interested in seeing how well the digipots perform at
1.1 and 1.3MHz.

So, the ideal digipot is,
1. >= 256 log. steps.
2. operates at 1.3MHz with < 3dB loss (I can compensate with the opamp).
3. <= 30 degree phase change between 1.1 and 1.3MHz sines.
4. <= SOIC8 package.
5. No output buffer.
6. Absolute rather then incremental control (though I probably could work with
the later if necessary).

An alternative is a serial input D/A converter combined with an opamp however
again dynamic response is questionable at 1.3 MHz and first tests would be
important.

Thank you,

Declan Hughes
(please remove abc if replying by email)


In article <vtf48qdehs3mfe@corp.supernews.com>, "Walter Harley"
<walterh@cafewalterNOSPAM.com> wrote:

"Declan Hughes" <dhughes@abcaero.tamu.edu> wrote in message
news:br7dsn$391$1@news.tamu.edu...
Hello,

I am looking for a few (4->10) 256 step linear digital pots in small
packages such as the MAX5402 (8uMAX). These are scheduled to ship from
Maxim
in February/12/2004.

This seems to be what everyone says about using parts from Maxim...
availability is poor.

Considered an alternate manufacturer?

 

[David Gillooly]

Try Mouser Electronics as they have the Catalyst Semiconductor part in
stock:

http://www.mouser.com//index.cfm?handler=search.getPcodes&pcode=Catalyst%20Digital%20Potentiometers%20-%20Single%20100-TAP&pcodenumber=69808


Dave


"Declan Hughes" <dhughes@abcaero.tamu.edu> wrote in message
news:br85hl$en$1@news.tamu.edu...

Yes, I looked at Winbond, Catalyst Semiconductor, Analog Devices, Xicor
and
Microchip as well as Maxim. I need to pass an FSK 1.1 or 1.3 MHz
sinusoidal
signal through this pot. into the +input terminal of an op-amp, and the
ideal
digipot would have >=256 logarithmic steps. The dynamic specs. for these
devices are typically sparse, however the MAX5402 datasheet states the
"Wiper-Settling Time ts To 50% of final value from code 0 to code 128 =
100
ns". The MAX5402 has 256 steps and no output buffer (which might further
constrict its frequency response). I also want a small package, <= SOIC8 .

The CAT5116RI has only 100 steps, however they are logarithmic (which
is good). It has a frequency response of 1.7 MHz when operated as a
passive
attenuator at 10 kohm (full R is 32k). This is a new part and I could not
find
a source with stock in their list of distributors. I called their Houston
office today and they will see if they can get samples.

In the worst case the prototype will go ahead without the variable
intensity
feature, and this will be added Feb/2004 when the Maxim parts arrive
(hopefully). I am also interested in seeing how well the digipots perform
at
1.1 and 1.3MHz.

So, the ideal digipot is,
1. >= 256 log. steps.
2. operates at 1.3MHz with < 3dB loss (I can compensate with the opamp).
3. <= 30 degree phase change between 1.1 and 1.3MHz sines.
4. <= SOIC8 package.
5. No output buffer.
6. Absolute rather then incremental control (though I probably could work
with
the later if necessary).

An alternative is a serial input D/A converter combined with an opamp
however
again dynamic response is questionable at 1.3 MHz and first tests would be
important.

Thank you,

Declan Hughes
(please remove abc if replying by email)


In article <vtf48qdehs3mfe@corp.supernews.com>, "Walter Harley"
walterh@cafewalterNOSPAM.com> wrote:
"Declan Hughes" <dhughes@abcaero.tamu.edu> wrote in message
news:br7dsn$391$1@news.tamu.edu...
Hello,

I am looking for a few (4->10) 256 step linear digital pots in small
packages such as the MAX5402 (8uMAX). These are scheduled to ship from
Maxim
in February/12/2004.

This seems to be what everyone says about using parts from Maxim...
availability is poor.

Considered an alternate manufacturer?