Does anybody have experience with both Fairchild KSA992 and Zetex (now Diodes Inc.) ZTX795A as input dif pairs? Any experience comparing the two is appreciated.

The ZTX supposedly have a little more bandwidth — but I'm not fluent enough in data sheets to discern if there are other benefits from one or other other. ZTX seem to be easier to match—but I don't know about their linearity or noise.

FWIW, I have ZTX pairs with Vbe identical to within ∆Vbe=2±2µV and beta identical to within 0.002% (my measurement precision). Best I can do on the Fairchilds is about ∆Vbe~100µV.

I'm not sure it's a meaningful parameter, but I've also computed ∂(∆Vbe)/∂Ic at my operating point of Ic=1.2mA, and the ZTX have a factor of 10 smaller slope.

For people looking to match their own in the future: Distribution of Betas (hFE) on my ZTX sample has mean of 380 and standard deviation of 19. Distribution on the Fairchild's (FB gain grade) has mean of 429 and standard deviation of 17.

The ZTX supposedly have a little more bandwidth — but I'm not fluent enough in data sheets to discern if there are other benefits from one or other other. ZTX seem to be easier to match—but I don't know about their linearity or noise.

FWIW, I have ZTX pairs with Vbe identical to within ∆Vbe=2±2µV and beta identical to within 0.002% (my measurement precision). Best I can do on the Fairchilds is about ∆Vbe~100µV.

I'm not sure it's a meaningful parameter, but I've also computed ∂(∆Vbe)/∂Ic at my operating point of Ic=1.2mA, and the ZTX have a factor of 10 smaller slope.

For people looking to match their own in the future: Distribution of Betas (hFE) on my ZTX sample has mean of 380 and standard deviation of 19. Distribution on the Fairchild's (FB gain grade) has mean of 429 and standard deviation of 17.

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