[time-nuts] 5>10 doubler

[Charles Steinmetz]

I had forgotten about one quite promising candidate -- the THAT300 
matched monolithic quad.  I have some of those, too.  I'll put it on 
the to-do list.  To the best of my knowledge, they do not have 
reverse protection diodes across the B-E junctions (I've never had 
any reason to check).

Best regards,

Charles



>I wrote:
>
>>>Once upon a time, Motorola made monolithic quad BJTs -- but I'm 
>>>not aware of any matched quads similar to 2N2222s at this time.
>
>Gerhard replied:
>
>>There still are
>>MAT04
>>HFA3046-3096-3127-3128
>>
>>if duals are enough:
>>SSM2220
>>MAT12
>>also mat02, mat03, maybe SSM2110 [probably meant SSM2210?  also, 
>>there is SSM2212]
>
>I had thought of these, but unfortunately, all of the AD parts (MAT 
>and SSM) -- which otherwise look promising -- have reverse diodes 
>across the B-E junctions, which rules them out as diode substitutes.
>
>The HFA parts are small-geometry, ultra-high frequency devices (Ft = 
>8GHz for the NPNs), not at all like 2N2222s.  It is doubtful they 
>would have the low flicker noise of 2222s.  They are monolithic, so 
>they should be pretty well matched, but only the differential pair 
>in the 3046 is actually specified for matching -- and you couldn't 
>use both of the diff pair in a ring structure because of the common 
>cathodes.  The 3127 would be the part to try.  I have some, so maybe 
>I'll try them (but I'm not hopeful).
>
>Best regards,
>
>Charles