[time-nuts] ULN regulator with more current capability than LT3042?

Charles Steinmetz csteinmetz at yandex.com
Sun Mar 18 18:43:41 EDT 2018


Tom wrote:

> Run two in parallel for twice the current and less noise?

This is actually a better solution than using an LT3045, for two 
reasons.  First, as Tom noted, by paralleling two devices, the noise is 
reduced by sqrt 2 = ~1.4:

"Designed as a precision current reference followed by a high 
performance voltage buffer, the LT3042 is easily paralleled to increase 
output current, spread heat on the PCB and further reduce noise -- 
output noise decreases by the square-root of the number of devices in 
parallel."  [LT Journal of Analog Innovation, v25 n1 Apr 2015]. 
<http://www.linear.com/docs/46398>

Second, it reduces the dissipation of each regulator, so they run 
cooler.  And as LT says, it allows spreading the heat on the board (but 
it is not advisable to put them too far apart).

The primary disadvantage is that two 3042s cost about half again more 
than one 3045.  Also, board space may be a factor in some applications.

So, unless you are extremely tight on board space or the ~1.5x cost 
increase is prohibitive, two 3042s in parallel are a better solution 
than one 3045 if you are seeking the lowest noise possible.

Best regards,

Charles




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