TL4242 Current Accuracy at 70mA

Alexander Scheuermann

Other Parts Discussed in Thread: TL4242

We are wanting to use the TL4242 at 70mA and wanted to know how accurate the current will be at this light load condition. It looks like the datasheet only goes as low as ~170mA (top of page 4), but I am sure that at this low current the accuracy will be a little worse. I was hoping you could give me some approximate numbers for this. Thanks!

over 11 years ago

0 Avi Chami1 over 11 years ago

Mastermind 7395 points

Take a look also at the graph on page 5, it goes a bit under 100mA for a 2Ohm external resistor

Best regards

Avi

0 Alexander Scheuermann over 11 years ago in reply to Avi Chami1

TI__Genius 14890 points

The graph on page 5 just shows you the Rref resistance you need to program the output current. My question is about the accuracy of the current when it is set to 70mA, so your answer doesn't really help. I appreciate the comment anyways.

0 Avi Chami1 over 11 years ago in reply to Alexander Scheuermann

Mastermind 7395 points

Well, you weote that the datasheet low limit was over 170mA so I thought it could help by pointing another section where lower currents are shown. The formula even is said to be valid up to 10Ohm, which would be well below 70mA. Anyway, let's hope you receive a better answer.

0 Dick Stacey over 11 years ago

TI__Genius 14890 points

Alexander,

I have not been able to locate the characterization data that would answer this question precisely. Is your concern mainly the accuracy of the IQ = VREF / REF relationship or the device to device skew? I have looked at this device in the lab previously and the currents follow the equation through 10 ohms.

I will try to get the data you need, but am not sure how quickly I will be able to do it.

Regards,

Dick

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TL4242 Current Accuracy at 70mA