Questions about Transistors with high beta (hfe) up to 3000 without Darl.-Topology
 

Single transistors (i. e. without internal darlington topology) with very high hfe up to 3000 are not often to find.
Here some examples:

NEC 2SC3616
http://www.classiccmp.org/rtellason/...ta/2sc3616.pdf
NEC 2SC3622 - 2SC3624 (1000-3200)
http://www.classiccmp.org/rtellason/...ta/2sc3624.pdf
http://www.datasheetcatalog.org/data...s4d8q8si3y.pdf
http://www.datasheetcatalog.org/data...8kuyykgefy.pdf
Sanken 2SC3852
http://www.sanken-ele.co.jp/en/prod/...f/2sc3852e.pdf
Sanyo 2SC3807
http://www.datasheetcatalog.org/data..._e/2SC3807.pdf
Sanyo 2SC3689 (800-3200) / 2SA1434 (500-1200)
http://www.datasheetcatalog.org/data..._e/2SC3689.pdf
http://www.datasheetcatalog.org/data..._e/2SA1434.pdf
Sanyo 2SC3068/2SA1435
http://www.datasheetcatalog.org/data..._e/2SC3068.pdf
http://www.datasheetcatalog.org/data..._e/2SA1435.pdf
Sanyo 2SC3576
http://www.datasheetcatalog.org/data..._e/2SC3576.pdf

Which benefits are there in opposite to a darlington topology?

Are there particularly suited for certainly amplifier topologies?

Which certain applications are there, where normal darlingtons are not a good choice?

Thank you for comments.

Interesting. These are like the "super-beta" devices found in some old opamps.
They were obviously specced for switching as the current does not go below 10mA in the gain graphs. You get high beta by having a very thin base, which gives low Vceo
The ft is good compared with a darlington and saturation voltage is much lower

Ill add some to that list in a day or two.

High voltage ones are available, I use them in inputstages and in beta enhanced vas sometimes.
Great for input LTP s as it improves DC offset problems.
MPSA18 is probably the most used one, excellent for LTP.
Higher current examples are excellent for use as VBE multipliers.

I am interested in the possibility of using a super-beta driven by a tube because small signal tubes don't like to drive into the relatively low impedance of a regular BJT. So I'm wondering how do they compare with FETs (also tube friendly to drive) in terms of linearity, capacitance and reliability ?

I wouldn't call the MPSA18 a super-beta, with Hfe > 500, not that much better than the old BC549C.
With Ft of about 100MHz, gain is going to start falling at around 100KHz

At a first look you are don't right. Now I do understand the reason, why this type is often to find by LTP's in old american power amps.
MPSA18 MOT: hfe 500-1500 (DC, Ic = 10mA)
http://www.datasheetcatalog.org/data...ola/MPSA18.pdf
BC546C-BC550C NXP hfe 420-800 (DC, Ic = 2mA)
http://www.nxp.com/documents/data_sheet/BC549_550.pdf
http://www.radiotechnika.hu/images/BC546_50.pdf

go also to
http://www.diyaudio.com/forums/pass-...s-bc546bs.html

But to a closer view to the exactly curvatures you are right with your view in your previous post because it is not possible, to compare the mentioned current gain values without the conditions of measurement. Sometimes the collector currents are different, sometimes the Uce voltage. Additional this is still a frequency dependend value (compare DC-HFe and AC-HFe).

Unfortunately all the other high Hfe types from Motorola's MPS-series are darlingtons:
mps6724-6725
mpsa12-14-13-25-26-27-28-29-62-63-64-65-66-75-76-77

mpsd04-54 (only1000)
mpsu45-95
mpsw13-14-45-45a-63-64

BTW - The MPSA18 is sourced from Process 07 (according an old Fairchild Databook)
other types from this process are follow:
http://www.fairchildsemi.com/ds/2N/2N5088.pdf
http://sm0vpo.com/_pdf/BC/BC847S.pdf

more high current gain types:

2N5963 Fairchild (hfe 1200-3000, no genuine datasheet and no successor in S. M. T. resp. SOT23 outline)
http://www.datasheetcatalog.org/data...ekerhelicy.pdf

2N5962/MMBT5962 Fairchild (hfe 600-2000)
http://www.fairchildsemi.com/pf/MM/MMBT5962.html
http://www.fairchildsemi.com/ds/MM/MMBT5962.pdf

MPSA18 (Onsemi, hfe 500-1500)
http://www.onsemi.com/pub_link/Collateral/MPSA18-D.PDF

2N5088-2N5089 Onsemi hfe 450-1800
http://www.onsemi.com/pub_link/Collateral/2N5088-D.PDF
http://www.onsemi.com/pub_link/Colla...T5088LT1-D.PDF
MMBT6428LT1G + MMBT6429LT1G (Onsemi hfe 500-1250)
http://www.onsemi.com/pub_link/Colla...T6428LT1-D.PDF

2N5828A General Electric, Semiconductor Data Book 1971 hfe 200-800)
2N5828 datasheet and application note, data sheet, circuit, pdf, cross reference, pinout | Datasheet Archive

2N5526 TI (no datssheet)

2N5249 (GES = General Electric Semiconductor) hfe 40-800
2N5249 pdf, 2N5249 description, 2N5249 datasheets, 2N5249 view ::: ALLDATASHEET :::

2N5223 (Fairchild hfe 50-1600)
2N5223 pdf, 2N5223 description, 2N5223 datasheets, 2N5223 view ::: ALLDATASHEET :::

MMBT5223 (hfe 50-800), MMBT2484 (hfe 250-800)
MMBT5223 datasheet and application note, data sheet, circuit, pdf, cross reference, pinout | Datasheet Archive

2SC2545, 2SC2546 Hitachi (hfe 250-1200)
http://jm.plantefeve.pagesperso-orange.fr/2SC2547.pdf

ZXTN07045EFF (Zetex hfe 500-1500)
http://www.diodes.com/datasheets/ZXTN07045EFF.pdf
ZXTN07012EFF (Zetex hfe 500-1500)
ZXTN07012EFFTA pdf, ZXTN07012EFFTA description, ZXTN07012EFFTA datasheets, ZXTN07012EFFTA view ::: ALLDATASHEET :::
ZXTP25012EFH (Zetex hfe 500-1500)
http://www.diodes.com/datasheets/ZXTP25012EFH.pdf

Dual Transistors:
ZXTC2061E6 (Zetex Dual Transistor, hfe 500-1500)
http://www.diodes.com/datasheets/ZXTC2061E6.pdf
MBT6429DW1T1G (Onsemi Dual hfe 500-1250)
http://www.onsemi.com/pub_link/Colla...429DW1T1-D.PDF
UMZ1NT1G (Onsemi Complementary Dual Transistor hfe 200-400)
http://www.onsemi.com/pub_link/Collateral/UMZ1NT1-D.PDF

A closer look at the datasheets will give you a better answer, compare apples with apples. The bc549C has a hfe of 500 at 2ma while the mpsa18 has more than double that (1100) at the same IC. The hfe of 500 you state for the mpsa18 is at 10 ua, at this current level the bc549c only manages 150. Also the ft of mpsa18 is around 400Mhz at 10 ma and still rising while the bc549c manages max ft of 300Mhz at 10Mhz whereafter it starts declining. The mpsa18 is far superior to the bc549c series in all respects, including lower noise and lower Cob too.

More high gain examples from Japan:
2SD2159 (Rohm hfe 390-2700)
2SB1461/2SB1425 (Rohm hfe 270-1200)
2SD2172 (Rohm hfe 560-2700)
http://www.datasheetcatalog.org/data...90/90250_1.pdf
No datasheet online

2SD2356-2SD2226K (Rohm hfe 560-2700)
2SD2227S (Rohm hfe 1200-2700)
Datasheet from March 1997:
2SD2171S pdf, 2SD2171S description, 2SD2171S datasheets, 2SD2171S view ::: ALLDATASHEET :::

2SC3615/2SC3616/2SC3622/2SC3622A (NEC hfe 800-3200)
2SC3615 pdf, 2SC3615 description, 2SC3615 datasheets, 2SC3615 view ::: ALLDATASHEET :::
2SC3616 pdf, 2SC3616 description, 2SC3616 datasheets, 2SC3616 view ::: ALLDATASHEET :::
http://www.datasheetcatalog.org/data...8kuyykgefy.pdf

2SA1409, 2SA1410 (NEC no data)

Any improvement in some caracteristics will inevitably reduce the abilities
of the device in some other areas.

The Hitachi/Renesas 2SA872/2SC1775 complementary pair
has respectable gain of up to 1200 , certainly less than the super beta
devices debated above , but more certainly they have high VCE and FT ,
very low noise and are somewhat a very wise compromise in matter of global caracteristics.