TINA/Spice/LMV7219: Why it is not working while the power supply is set at 3.3V?

Hongmei,

Could you please attach the schematic file of your simulation? This will help us try to solve your problem as soon as possible. Please expect a delay in response over this weekend.

Regards,

Jonny

Hi Jonny,

I attached the simulation file (see below) using "insert file". I can't see it. I am not sure if you can see it or not. The file is same as the previous .png file but it is simulation file.

PositiveCurrentProtection.TSC

if V1=5V, then when Vi1+>Vi1-, Vo is high; Vi1+<Vi1-, Vo is low; 

if V1=3.3V, then Vo stays low at any situation.

Thanks,

Hongmei

PositiveCurrentProtectionTLV3501.TSC

Hongmei,

When using the LMV7219, the input common-voltage range is typically Vcc-1.

With a 3.3V Vcc, the input range is from 0 to 2.3 V. Since the reference voltage was set to 2.5V in your design, the comparator will not output a logic high. The 5V Vcc worked because it increased the input range of the comparator.

I suggest you use the TLV3501 high speed comparator if you would like to detect rail to rail inputs. The TLV3501 has a 4.5ns delay and should work in your design for both supply values. I have attached a TINA file with the new comparator I suggested.

Regards,

Joe

Hi Joe,

TLV3501 is very good but the footprint is different.

Can you please possibly provide me the LMV7239 model in the .TSC simulation file or another better part suggestion with footprint of SOT-23-5? I look for LMV7239  in every single folder in my TINA but can't find it.

Thanks,

Hongmei

Thank you very much, Jonny.