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Programmable from 1µA to 10mA. □ ±3% initial accuracy. Description. The LM/LM/LM are 3-terminal adjustable current sources characterized by . LMM Texas Instruments Current & Power Monitors & Regulators NRND, alternate is LMM/NOPB datasheet, inventory, & pricing. LMM/NOPB Texas Instruments Current & Power Monitors & Regulators 3- TERM ADJ CURRENT SOURCE datasheet, inventory, & pricing.

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So if you monitor the voltage across the LM perhaps with a comparator you can have a good idea of whether it is working or not. All satasheet that is true.

This will lm334m over temperature and from unit to unit, that’s what they mean by ‘typical’. Furthermore, I think it’s rather crazy that you allow such high ground impedance 10k. The divider produces about 0. Email Required, but never shown. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

If it’s less than that it may or may not be working there is no minimum voltage below which is it is guaranteed to not work. If the load impedance is high, then the current will be much lower than the limit. When the 1 mA of current is reached, it should begin to increase its resistance, thus increasing the voltage drop across it. If anyone else has an idea of how to light an LED when an LM is actually limiting the current through it, that would work too.

It belongs in the question.

LMM/NOPB – Texas Instruments – PCB Footprint & Symbol Download

The typical performance is shown in the eatasheet in this graph: The load has a variable impedance. It’s not possible to give a good answer without much more information such as a complete schematic and accuracy requirements. If the load impedance is low, then the current will hit the limit. I’d expect it to be minimal, however, since the should be trying to pass as much current dtaasheet it possibly can. Sign up or log in Sign up using Google.


The detection threshold would be something like 1V.

The circuit in this case is a Ground Continuity Monitor. My goal is to make an alarm of sorts when that dqtasheet exceeds a threshold, and the way I want to do that is to detect when the is in current limiting mode.

The current limiter is intended to limit the amount of ground leakage. At least, that’s my thinking at the present.

Tyler Think of it rather as a current limiter. A couple of resistors and a comparator with built-in reference would do the job in a much simpler fashion.

Sign ratasheet using Email and Password. The intent now is to connect the output to ground and measure the voltage drop across it instead. So what you do is connect R2 directly between L and PE terminals.

Remember that this circuit must act appropriately during faults – and then the LM is a short. It’s also intended to at least attempt to desensitize the circuit to the tolerance variation of the k resistor and the supply voltage.

The actual earth is on the far side of R1. In the case of the LM, it is rated with a fatasheet drop of 2. The question at hand is how best to detect when the voltage across the LM exceeds a threshold.

LM from Texas Instruments

If it is a “constant” current source, why is the current “variable”? I’d like to measure the voltage drop and light an LED really an optoisolator when it exceeds a threshold.

The LM in this case does not have an infinite voltage with which to overcome the datashee impedance. Please edit your question and delete the comment. At 25C, the LM has a minimal drop-out voltage of about 0.

  DIN 69901 5 PDF

So for low currents, it might be delivering more-or-less constant current at 0. So if the LM xatasheet connected low side and sinking 1mA, and you want to know when the forward voltage drops below 1V you can use a comparator with a 1V reference. You can increase the resistance of the divider if you can use a larger load resistor R3 or a higher-gain transistor.

In the schematic, I1 represents the LM When it’s passing less than 1 mA of current, I would expect it to be acting like a very low-value resistor, meaning that the voltage drop across it should be low. It depends on GREATLY on how the Lm334mm is connected high side or low side, for example and how much your current is and how much error you can tolerate any monitor circuit will lower the output impedance.

The reference could be derived from a datashwet supply voltage such as 5V with a voltage divider.

Datasheet «LM334»

The comparator could be something like half an LM You need a different design, and I question the need for a current source. R2 completely determines the behavior of the system, when looked at from outside, and sets the leakage current.

Sign up using Facebook. Spehro Pefhany k 4 Nope, it won’t dxtasheet. From there, it’s just a matter of tuning either the set resistor of the LM or the voltage threshold to trim to the setpoint. Any real current source will have a voltage limit beyond which it will not deliver a constant current. I don’t see a way in circuitlab to represent an actual LM, so the simulation likely won’t operate datashet.