General Description. The AS and AS are junction isolated ultra well- matched monolithic NPN transistor pairs with an order of magnitude improvement in. LM/LM Supermatch Pair. General Description. The LM and LM are junction isolated ultra well- matched monolithic NPN transistor pairs with an. LM datasheet, LM circuit, LM data sheet: NSC – LM/LM Supermatch Pair,alldatasheet, datasheet, Datasheet search site for Electronic.
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The transistors might be on separate dies for all I know. I just get the default circuit. I don’t know what the definitive chip datasehet but there are many chips that implement the whole circuit. Octopart is not comprehensive. So Maxim doesn’t have any either. To see a list of open positions, click here. I’d rather the LOG and skip the Maxim hassle. What is the new standard log amp circuit?
It seems that this xatasheet not recommended for new designs but the replacement is the MAT I tried adjusting the Hfe of the transistors and unless it was something like it kept a very clean log output. This circuit uses the difference of two transistor currents to generate the log of the input over a pretty wide range.
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Thank you for your interest in this question. Two LMs can be stacked to get 60 dB range. TI still lists the part in their catalog, but designates it as obsolete. Would you like to answer one of these unanswered questions instead? The well-matched transistor pair Q1a and Q1b are halves of the LM “supermatch” transistor pair. Devices equivalent to the LM are now being made by another company: Maxim direct is saying 15 weeks lead time for single parts.
Intersil makes a number of transistor arrays some are certainly single die and well matched. If you modulated the reference voltage by 3dB, the output would probably average to about the right value.
This is probably not the way to go unless there is a need for an LED bargraph in the circuit already. Joseph Perkins 1 1. For example, does not search Maxim-Direct, i. Those “transistors” are identical.
Open Positions To see a list of open positions, click here.
Chris Johnson 7 That’s an interesting forum thread, especially the story about MAT For details on these services, please click the appropriate link from the menu on the left. Engineering Program is accredited by: So no cheaper than the LOG How can I cheaply make a logarithm?
However, I’m not sure how suitable it is for your application. MAT12 is still in production, but octopart. The traditional logarithmic amplifier circuit is described in National Appnote I had this idea for a quick and dirty log amp.
LM Datasheet(PDF) – National Semiconductor (TI)
As usual, Maxim dataheet do not exist. Home Questions Tags Users Unanswered. This circuit looks to be a log amplifier using two op-amps, two transistors, a few passives and a current source.