Low noise transistor

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Hej

Er der nogen der kender en god og meget støjsvag transistor der kan erstatte
en BC857


--
Peteropfinder
Peter N. Petersen
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Re: Low noise transistor [ ROHM 2SA1455k, 2SC3722k, NF ca.= 0,2 dB? ]
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Hej Peter

BC857 er en PNP.

SMD udgaver af BC560 (komplementær BC550) (BC559 og BC549 har lidt
højere støjtal) - BC860:
http://www.nxp.com/#/pip/pip =[pipBC%859_BC860_5]|pp=[v=d,t=pip,iBC%859_BC860_5,fi47%295,ps=0][0]

SMD udgaver af 2SA970 (komplementær 2SC2240).

SMD udgaver af 2SB737 og 2SD786 (kan ikke huske hvilken er PNP).


Kig f.eks. på:

diyAudio Forums Archive - Low noise transistor and noise figure:
http://www.diyaudio.com/forums/showthread/t-39680.html
Citat: "...
The lowest noise audio types i have ever seen are ROHM 2SA1455k and
2SC3722k they have a noise figure of just 0,2 dB. They are suitable for
normal line level impedances like 1 - 22k.
...
If we talk about it, SSM2210 and SSM2220 from Analog Devices are also OK
but they have other unwanted properties (you can't have it all)
...
There are also leaded versions of 2SA1455k / 2SC3722k, they are called
2SA1038 + 2SC2389.
...
Rohm is dicontinuing the A1038 & C2389. They want us to buy the SM versions.
...
I am looking at MAT01 noise specs. At first they appear not so
good with around 6nV/rt Hz (P2 data sheet), but on further
inspection this appears to be at 10uA (see top of page 2).
Comparing to the super low noise MAT02, at 10uA it is pretty
similar and acheives best noise specs at a few mA.

So does anyone know what the MAT01 specs at a few mA?
Or is the data sheet wrong?
...
What do you think about low noise transistor arrays made by THAT
Corporation.
THAT300 4xNPN
THAT320 4xPNP
THAT340 2xNPN
http://www.profusionplc.com
...
mandat! thanks you very much!
I can't say anything about lownoise and fT .325Mhz is a ultra high
frequency. fT of 2sc2240,2sc2362 and 2sc1815 is about 100Mhz
That 340 is very suite for building a symmetrical amp.But Beta is a
problem, about 60-100 is very low .
..."

-

Husk at det måske så er en god idé at anvende metalfilms modstande, da
de støjer lidt mindre end kulfilm...

hilsen

Glenn

Re: Low noise transistor [ ROHM 2SA1455k, 2SC3722k, NF ca.= 0,2 dB? ]
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http://www.nxp.com/#/pip/pip =[pipBC%859_BC860_5]|pp=[v=d,t=pip,iBC%859_BC860_5,fi47%295,ps=0][0]
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737'eren er en PNP.
De er "end of life" og svære at få fat i! Kan de overhovedet fåes i SMD???
Købte for et stykke tid siden nogen leadede (dyrt) i Østen til LC Audio.

Mvh.
 Anders


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Re: Low noise transistor [ ROHM 2SA1455k, 2SC3722k, NF ca.= 0,2 dB? ]

Tak for dine foreslag.


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2SA og 2SB er PNP
2SC og 2SD er PNP


--
Peteropfinder
Peter N. Petersen
We've slightly trimmed the long signature. Click to see the full one.
Re: Low noise transistor [ PNP array THAT320? ]
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Hej Peter

Disse ser også gode ud, men er pakket ind med flere andre:

http://www.profusionplc.com/pro/gex/prodGen.html?prdtyp=transistor%20arrays
Citat: "...
When it comes to matched transistor arrays, you're not likely to find
any better than THAT Corporation's 300 series.
...
Their low base-spreading resistances and voltage noise under 1 nV/rt-Hz
make the 300 series ideal for low-noise amplifier input stages, among
other applications. Because they are fabricated in a dielectrically
isolated (DI), complementary bipolar process, each transistor is
electrically insulated from the others by a layer of insulating oxide
(and not the reverse-biased PN junctions used in conventional arrays).
*Consequently*, the THAT300 series exhibit inter-device crosstalk and DC
isolation similar to that expected from discrete transistors - *perfect*
for audio applications!
..."

når de nu selv skal skrive det...

hilsen

Glenn


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