TPS3702-Q1: current into Vsense Pin

Hans

Part Number: TPS3702-Q1

Hello Team,

according to the data sheet the max current into Vsense-Pin is specified with 1.5uA at Vsense = 5V. This is valid for TPS3702CX50, correct?

Question:
Will the Vsense current be proportional to Vsense voltage or will is stay constant for the different versions (TPS3702CX12, TPS3702CX18, TPS3702CX33)
In other words: Is the resistance of the 3 resisistors the same for all versions or does it change with the version?

If the current stays at 1.5µA for all variants at Vsense = 5V will TPS3702CX12 Isense,max be proportional lower: Isense(max) = 0.36uA @ 1.2V?

Is the sum of all 3 resisitors constant over all variants?

Thanks and Best Regards,

Hans

over 5 years ago

0 Ethan T over 5 years ago

TI__Expert 3835 points

Hi Hans,

Yes 1.5uA max is spec for all voltage options. The resistor are trimmed to trigger at different voltage thresholds option. The resistors are different which means that I_sense maximum current should be lower at lower voltages, but we can't guarantee. The sum of all 3 resistors is not constant over variants.

Hope this helps,
Ethan

0 Hans over 5 years ago in reply to Ethan T

TI__Genius 12865 points

Hi Ethan,

thank you.

Just one question:

If the current stays at 1.5µA for all variants at Vsense = 5V will TPS3702CX12 Isense,max be proportional lower: Isense(max) = 0.36uA @ 1.2V?

Is this calculation correct or wrong?

Thanks and Best Regards,

Hans

0 Ethan T over 5 years ago in reply to Hans

TI__Expert 3835 points

Hi Hans,

This is a correct calculation, assuming 1.5 uA at 5 V and a linear relationship between the I_sense current and voltage.

Regards,

Ethan

0 Adrian Helwig over 5 years ago in reply to Ethan T

TI__Expert 3840 points

Team,

the customer did some measurements with our samples (see attachment), but the input current seems to higher then 1.5uA.

They used the application schematic from the datasheet.

Could You please comment on that?

Regards

Adrian

TPS3702_sense_current_data.xlsx

0 Adrian Helwig over 5 years ago in reply to Adrian Helwig

TI__Expert 3840 points

Team,

any news on that?

regards

Adrian

0 Ethan T over 5 years ago in reply to Adrian Helwig

TI__Expert 3835 points

Hi Adrian,

I apologize, I was out office. The new E2E power management forum also turned off my notifications.

I have looked at the excel and noticed they used a series resistance in order to calculate the input current. I would be a little skeptic since this is not how we test our devices for sense current. I would recommend a separate supply to SENSE and calculate the current with an amp meter.

If the customer believe they have defected devices then have them contact their local TI CQE to provide customer return units.

Thanks,

Ethan

Power management

Power management forum

TPS3702-Q1: current into Vsense Pin