I need to replace a shorted TL750L05 +5V voltage regulator with a new one. The problem is I can not easily find a replacement part that has the same features. I found the LM2931M-5.0 but is rated at 100mA max output current instead of 150mA of the original TL750L05. How bad it would be for my smps (the regulator is used in the secondary circuit of the switched mode power supply as an output voltage) and how long it will last ?

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    \$\begingroup\$ Your title says "SMPS" yet the device you ask about isn't an SMPS, it's an LDO. That's confusing! You can use the LM2931M as long as you do not violate its ratings. So if the load draws less than 100 mA then you can use the LM2931M. \$\endgroup\$ – Bimpelrekkie Oct 3 '18 at 10:08

It depends on what the actual load is. If the load really draws most of the 150 mA available from the existing regulator, then you can't replace it with a 100 mA regulator. If the load only draws 100 mA or less, then a 100 mA regulator is fine.

I just looked and the TL750L05 is a linear regulator, as the name hints. It is not a SMPS (switch mode power supply). However, the answer about a replacement is the same. Either way, you have to make sure any replacement can provide the current that the load needs. You have to start with finding what that is.

  • \$\begingroup\$ Hi, yes obviously you have right. The problem is I dont know the how much current the load draws.... I was hoping to be less than 100mA but to be sure I have to search for a replacement with 150mA max load. The regulator is used to a SMPS, I am not sure I really understand your point. \$\endgroup\$ – Maverick Oct 3 '18 at 11:18
  • \$\begingroup\$ @Maverick do you mean the regulator is used to power an SMPS? The way your question is worded suggests that you are calling the TL75L05 an SMPS, that was the point Olin was making. If you meant that the linear regulator is used to power an SMPS, you may want to consider re-wording your question, or posting a schematic, otherwise that information is unclear to people reading \$\endgroup\$ – MCG Oct 3 '18 at 11:30
  • \$\begingroup\$ the regulator is used as an output voltage in a switched mode power supply in the secondary circuit \$\endgroup\$ – Maverick Oct 3 '18 at 12:34
  • \$\begingroup\$ To figure out what the load draws, use a power supply (like a CPU power supply, or bench) that you know can supply >> 150 mA. Connect to the 5V output pin of the removed LDO, and measure the current drawn by the load. \$\endgroup\$ – Jim Oct 3 '18 at 13:25

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