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LT1037 Replacement - Wien-Bridge Oscillator

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iceblu3710

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I find it quite off but Mouser does not carry any products from Linear Technologies. I was looking for a LT1037 when I realized it.

So I need help trying to find a suitable replacement that I can get from Mouser. Here is the proposed project:

A Wien-Bridge Oscillator that has a THD = <0.05 with a noise floor of -100dB. I have sourced all the tight tolerance capacitors and the multi position rotary switch but without a very high quality op-amp the project is pretty useless. I am planning on putting two of these oscillators in a case with several additional stages. One would provide the sine wave output with amplitude and offset control. The Wien-Bridge would feed another two stages as well, one being a square wave with adjustable duty cycle and the other a sawtooth generator. Each can be generated from the previous however as each stage introduces noise the Wien-Bridge require a very clean and noise free output.

So anybody know a suitable op-amp?
 

FvM

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Re: [Moved] LT1037 Replacement - Wien-Bridge Oscillator

TI OPA227/228 would be my first choice for similar applications.
 

LvW

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Re: [Moved] LT1037 Replacement - Wien-Bridge Oscillator

Iceblue, it seems that the decision has been made already to use the WIEN bridge oscillator type.
I like to point to the fact that - in case you intend to vary the oscillation frequency - this oscillator type requires to vary two parts simultaneously. Didn't you consider other oscillator circuits?
 

iceblu3710

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Re: [Moved] LT1037 Replacement - Wien-Bridge Oscillator

@LvW - I am planning on using a close tolerance dual potentiometer to very the freq and the dual 4 position rotary switch to select different capacitors for the freq range. I am using Linears Application Note 5 - Page 8 as it is the highest quality oscillator I have seen.

I would consider other circuits but only if the meet my goal of <0.05% THD and a noise floor of -100dB. Do you know of any other solutions?
 

LvW

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Re: [Moved] LT1037 Replacement - Wien-Bridge Oscillator

@LvW - I am planning on using a close tolerance dual potentiometer to very the freq and the dual 4 position rotary switch to select different capacitors for the freq range. I am using Linears Application Note 5 - Page 8 as it is the highest quality oscillator I have seen.

I would consider other circuits but only if the meet my goal of <0.05% THD and a noise floor of -100dB. Do you know of any other solutions?
OK, no general objections. However, the THD value is determined by the amplitude stabilizing network - and the noise floor mainly by the op-amp and the associated resistors. That means, for my opinion, these requirements do not necessarily lead to the WIEN type oscillator. My only concern was the necessity of a dual potentiometer.
Another comment: If you dislike the proposed stabilization principle (PTC, lamps) you could apply also a thermistor with negative temperature characteristics in replacement of (or in combination with) the feedback resistor. I think this could simplify the parts selection (a broader variety of parts, types and time constants).
Good luck
LvW
 

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