2N5458

[janeecko]

PLs could anybody help me. I cant buy 2N5458 in my country. Who does know the alternate transistor for 2N5458
THNX

[Ge_Whiz]

2N5457 is a higher-performance (and therefore slightly more expensive) alternative. What circuit are you building?

[janeecko]

I´m building Rat from tonepad.com. I´ve bought everythings except this transistot. 5457 is not in my country too.
I think that i´m going to buy another transistor with the same parameters, but i don´t know which

[MartyMart]

MPF102 and J201 fets will do the same job as a 5457, J201 is slightly "hotter" so MPF102
would be my choice.

MM.

[janeecko]

thanx a lot

[Gus]

download PDFs of the devices and note the specs a 2n5458 is different than a j201 different dies IIRC the IDSS spec is different and some other specs are different.   

What are you building with it? sometimes you can change fets and sometimes you want a certain fet.

Can you get 5457s or 5459s the dies are the same.  The number difference is the sorting, they do overlap a little.

http://www.fairchildsemi.com/pf/2N/2N5458.html

google the j201 to see the difference in specs

BIG HINT vishay web site.

FETS are kind of like CPU speed ratings

[stm]

Ge_Whiz wrote:2N5457 is a higher-performance (and therefore slightly more expensive) alternative. What circuit are you building?

The 2N5457 is not a higher performance with respect to the 2N5458.  There are three members in this family, which are 2N5457, 2N5458 and 2N5459.  When these devices are manufactured, they are sorted based on the pinch-off voltages (Vp), so they roughly have average Vp's of 1.5V, 2.5V and 3.5V, respectively.

Depending on the particular application you may prefer one or the other.  In general, the lower Vp devices may allow higher gain in simple amplifier stages.  On the other hand, devices with higher Vp's such as the 2N5459 will tolerate hotter signals and introduce less distortion when used as a voltage-controlled resistor (i.e. phasers).

The MPF102 is a decent substitute for the 2N5458 and eventually for the 2N5459.  The J201 is way too different (much smaller Vp and Idss than the 2N5457).

In summary, for amplifiers or gain boxes I would reccommend the J201 and the 2N5457.  For phasers I'd rather use the 2N5459, 2N5458 and MPF102.

There are other FETs out there that are not suitable for the above applications because they have very low resistance and eat too much current.  However these devices are best suited as analog switches.  Examples of such are the J111 and the PN4392.

[WGTP]

Since it is being used for a Rat, I assume it is the buffer stage at the output.  I used a MPF102 that seems to work fine.  I know others have used something different.

[nordine]

since we're talking about FETs right now,

i'd like to know why i can't get any distortion with 2sk30's?
to get any distortion of them would it be as easy as to drive them with a previous mosfet booster stage?

[Gus]

what suffix 30's 

look around the vishay fet site, work out the math and you might find your answer.

[mac]

Both 2N545X and J201 are unavailable in my country.
I use MPF102, BF245C to replace high Vgsoff fets, and for any buffer.
BF245A, 2SK117 to replace J201. 2SK117 has very low Vgsoff and a lot of gain.


mac

[jimbob]

Mpf102 worked great in mine.

[SolderBoy]

janeecko, the pinouts vary from transistor to transistor also...