Noise Measurement Amplifier

[1audio]

The ztxp2027 looks interesting. The datasheet did not mention noise. A measurement of current noise would be important for bipolar parts since its may become dominant.

 

[MarcelvdG]

The white current noise is just base shot noise, sqrt(2qI_BB) over a bandwidth B. The 1/f part is hard to predict.

 

[jackinnj]

Table 8.1a, AoE3 shows I(noise) as 4.93pA/RtHz

 

[1audio]

Must be indifferent datasheet. Diodes.inc datasheet has no noise info.

 

[MarcelvdG]

AoE is short for Art of Electronics, which is not a databook.

Table 8.1a, AoE3 shows I(noise) as 4.93pA/RtHz

Under what conditions (collector current, frequency)?

 

[gerhard]

I think one page is fair use. You want that book anyway. (page 501)
Gerhard

 

[Hearinspace]

What is that book?

 

[gerhard]

< https://www.amazon.de/s?k=art+of+el...fix=Art+of+,aps,100&ref=nb_sb_ss_ts-doa-p_3_7 >

Be sure to get ed. 3, and maybe the X chapters (the stuff that did not fit into the
first 1192 pages)

Gerhard

 

[1audio]

A different caution, since that part is not made as low noise, process variations may cause noise problems but the part will still be a fine switch. You will need to test.

 

[Mark Tillotson]

The low Rbb is what makes it a fine switch though - in particular the very low Vsat (45mV at Ic=1A, Ib=100mA). More base spreading resistance will increase Vsat

The ZXTP2027 is basically the ZTX951 in surface mount (the device marking is "951" even!), same for the ZXTN2018 and ZTX851