Re: Copying Op Amps to Make Mic Amps



Jim Thompson wrote:

Eeyore wrote:
Jim Thompson wrote:
John Larkin wrote:

Some analog processes can use transistors as good as anything you can
buy as discretes. Opamps like LT1028 have noise below 1 nv/rt hz.

Oh, John! You're giving away my secrets ;-)

Where's your 500pV/sqrt Hz input device ?

In a multi-channel sonar chip I designed...

Process = PolarFAB BiCMOS... high beta and high fT NPN's AND PNP's
plus 0.8um feature-size CMOS

How much do they effectively cost ?

Graham

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