Author Topic: Replacement, Operational Amplifier DIL-8, MAX420EPA+  (Read 5985 times)

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Offline zz1969

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Replacement, Operational Amplifier DIL-8, MAX420EPA+
« on: December 26, 2012, 02:12:39 PM »
Hi P-A,

can you advise the replacement for Operational Amplifier DIL-8, MAX420EPA+ for QSXM2 as this part is obsolete and cannot be ordered.
Thank you.

Evgeny

Offline peranders

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Re: Replacement, Operational Amplifier DIL-8, MAX420EPA+
« Reply #1 on: December 26, 2012, 02:32:16 PM »
OP07 or similar will do fine. Choose a low drift, low offset and a low noise type. Slew rate 5-10 V/us is suitable.
« Last Edit: January 11, 2013, 08:56:36 PM by peranders »
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Offline tk-don

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Re: Replacement, Operational Amplifier DIL-8, MAX420EPA+
« Reply #2 on: February 03, 2014, 10:45:50 PM »
On the same topic: I'm also looking for a replacement and looked into current available chopper op-amps . I'm almost sure the LTC1050 is suitable for this task, similar specs to the MAX420 but with a slew-rate of 4V/us and GBW of 2.5 MHz. Do think this will work, P-A ?  :-)
http://www.linear.com/product/LTC1050
I know the input offset voltage of the OP07C is around 60 uV, which is low but still 20 times higher than the LTC1050. But the magnitude of uV suggests that it doesn't matter that much... or does it?

EDIT: Okay, it was discovered earlier: http://sjostromaudio.com/smf/index.php/topic,268.0.html - do the same comments apply for the QSXM2?
« Last Edit: February 03, 2014, 11:36:03 PM by tk-don »

Offline peranders

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Re: Replacement, Operational Amplifier DIL-8, MAX420EPA+
« Reply #3 on: February 04, 2014, 06:24:50 AM »
Max supply voltage is ± 8 V only. I recommend that you look for a conventional opamp.
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Offline tk-don

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Re: Replacement, Operational Amplifier DIL-8, MAX420EPA+
« Reply #4 on: February 05, 2014, 10:20:58 PM »
Thanks... You're right. I'll likely just go for OP07. Just got "provoked" by the LT1012 ( http://www.linear.com/product/LT1012 ) , which LT markets as a drop-in for OP07 with specifications that look better (lower offsets) and was thinking to use it where either the OP07 and MAX420 were used in the QSXM2. Or would this be considered incompatible in this application and/or purely a waste of money on improving figures that are already so small that it doesn't matter?
(This will be my last question, regarding this.. I promise!)
« Last Edit: February 05, 2014, 10:22:41 PM by tk-don »

Offline peranders

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Re: Replacement, Operational Amplifier DIL-8, MAX420EPA+
« Reply #5 on: February 05, 2014, 10:39:03 PM »
I think a noticeable disadvantage is some noise from chopper stabilized opamps. Right now you can find good normal opamps so the chopper technology is partly a bit unmodern.
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