Q. Data loss degree according to LT1328 mode

Hi,

I have contacted the responsible Apps Engr of this part and we'll provide feedback the soonest.

Thanks and regards!

Hi Leo:

Unfortunately I don't have any rigorous analysis of data loss with various setups.  I do know that the LT1328 performs quite well with SIR and FIR data.  The Mode switch really just sets the low frequency block rate.   In environments with a lot of low frequency background, it can help to set the block frequency higher.  For better SNR, you can use a more directional (and lower capacitance) photodiode such as SFH213, and/or blast more power into the transmitting LEDs.  In extreme cases, I have found that the JFET bootstrap method shown in DN399 (link below) can improve results in high frequency applications such as 4ppm where the incident power is varying a lot.  

https://www.analog.com/media/en/reference-design-documentation/design-notes/dn399f.pdf

I should add that the LT1328 is very sensitive.  It can even become too attentive to its own input noise.  In order to reject that excessive degree of sensitivity, a 3Meg pullup from the Bias pin to 5V works well.

Hi Glen.

Thank you for answer.

I will ask again if I have further questions.

Best regards, Leo