Can I use the LT3092 with negative voltages?

Question

I have a question regarding the operation of the LT3092. To demo its functionality as a programmable current source, I was able to simulate it in LTspice with the LT317A Positive Voltage Regulator to give the regulator a current limiting functionality. However, I was wondering if it could also work for negative voltages as well? For example, in the example image below, I would have the LT3092 in series with the LT337 negative voltage regulator to limit the current from the voltage regulator. Would this be okay as long as the voltages are within spec of the part (i.e., below 40 volts)?

charlyelkhoury · Accepted Answer

I don't think you are looking at this the correct way. 
 Please take a look at the simulation attached. 
 LT3092_Negative.asc 
 Although the LT3092 might operate in a negative supply at I show in the simulation, 
 The voltage that the IN pin will not be sitting at -35V as you are referenced to ground and your resistive load and load current will determine where the IN pin voltage. 
 Let me know what you think after looking at the Ltspice simulation. 
 Charly)

charlyelkhoury · Answer

I think you conclusion is correct; this will not act the way you want it to for this application. 
 As far as will this part work in negative environment like we used it in LTspice, the answer is yes, but for specific applications. 
 As long as we don't violate the parts limits it will be fine. 
 Charly

charlyelkhoury · Answer

the way you did it in this latest simulation is better, as your negative LDO is setting the negative voltage you need, and you are only using the LT3092 to limit the current, 
 If this looks good for your application, I would try it with the eval board just to make sure the voltage regulation is acceptable for your application before building your own board. 
 Charly.

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Can I use the LT3092 with negative voltages?

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