Формула для тока шума, Поясните, пожалуйста

РЇ:
Good afternoon. That300 arrays is very fine product, but I did
not see the current input noise specifications in datasheet. As you now,
this spec. is very important for low noise amp design - alongside input
voltage noise. Please, what input current noise of 300 series arrays, for 1
mA collector current? Best regards Urij

Ответ:
Hi Urij,

We do not measure current noise in our production tests. However, bench
characterization has shown that the spot current noise at 1 kHz follows the
formula for shot noise (in = sqrt[2qib]) very well. So, for a 1 mA
collector current and a beta of 200 the spot current noise would be: in =
sqrt(2*1.6e-19* (1mA/200) = 1.26 pA/rtHz.

At low frequencies there will also be a 1/f contribution. The 1/f corner
for the 300-series devices is typically a few hundred Hz. Since both of
these noise sources are a function of the magnitude of the base current you
should consider the high-beta versions of the 300 array if current noise is
a primary concern.

Regards,
Gary


Gary K. Hebert
Chief Technology Officer


45 Sumner Street
Milford, MA 01757 USA
+1-508-478-9200
www.thatcorp.com

Гмм.. не слышал я про такую формулу . Ткните носом, пожалуйста.

https://books.google.de/books?id=OAHW03OixH...20noise&f=false

не задирать сопротивление источника выше 1к - и пофиг на него...
Если оно выше - уменьшатъ ток и/или выбирать hFE повыше

Это сообщение отредактировал ДмитрийЗл - 2.10.2015 - 21:34