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In Reply to: Re: OPA2134 vs OPA2604 vs OPA637 posted by Ehien on January 30, 2002 at 18:29:43:
doubt that top grade, i.e. lowest offset voltage and/or military tempareature will do any good in audio applicationsany FET input op amp will have problems when used in non-inverting mode due to common-mode-input-voltage-dependend input transistor capacity causing distortion
the 6x7 may be less prone due to alleviating action of cascode circuit
the 627 and 637 are the same except for minimum noise gain - in applications above noise gain of 5, the 637 will offer higher bandwidth which helps to reduce hf and intermodulation distortion
look at D. Self web site - he tested op amp performance with an audio precision one unit - not the most meaningful test, but still, it is interesting to observe discrepancies to manufacuturers' data sheets! the OP-275 turns out to be pretty poor btw!
i have had good experience unsing a 627 in inverting mode and with a diamond transistor output buffer that keeps thermal influence from output load outside of the chip - minimizing thermal coupling and hence LF distortion
for non-inverting mode I recomment a fully complementary discrete op-amp
greetings,
Eric
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Follow Ups
- offset voltage, common mode distortion 627 vs. 637, output load - capslock 13:43:58 02/01/02 (5)
- Re: offset voltage, common mode distortion 627 vs. 637, output load - Thorsten 02:05:56 02/02/02 (3)
- Re: offset voltage, common mode distortion 627 vs. 637, output load - Elso Kwak 08:14:55 02/02/02 (2)
- Re: offset voltage, common mode distortion 627 vs. 637, output load - Thorsten 11:42:24 02/02/02 (1)
- Re: ???????????????????????(NT) - Elso Kwak 13:33:34 02/02/02 (0)
- Re: offset voltage, common mode distortion 627 vs. 637, output load - Ehien 16:06:19 02/01/02 (0)