Low noise transistor

Hej Peter

BC857 er en PNP.

SMD udgaver af BC560 (komplementær BC550) (BC559 og BC549 har lidt højere støjtal) - BC860:

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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:

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

... 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 . ..."

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

hilsen

Glenn

Hej Peter

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

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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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

"Glenn Møller-Holst" skrev i en meddelelse news:fjlbev$24u$ snipped-for-privacy@news.net.uni-c.dk...

Tak for dine foreslag.

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

--
Peteropfinder
Peter N. Petersen
http://Peteropfinder.dk