LM2705: The limit for the LM2705 FB pin upper resistance

Rock Shao

Part Number: LM2705
Other Parts Discussed in Thread: TLV61048, LM27313

Is there has a limit for the LM2705 FB pin upper resistance?

For TLV61048 as an example, the upper limit of voltage divider R2 must not exceed 150K ohm.
Because this parameter will affect the power consumption.

Besides, can you help confirm whether the power chock can use 4.7uH, and the overall power consumption is about 5mA? Did LM2705 has the calculation file? I can't found this part in the WEBENCH, thanks.

over 3 years ago

0 Zack Liu over 3 years ago

TI__Mastermind 34201 points

Hi Rock,

Just curious, why does you use a so old device? There are lots of new boost converter available.

For your questions.

1. When selecting the FB resistors, make sure the feedback resistor current won't be higher than 100*FB pin bias current (120nA)

2. I would suggest use the recommended inductor 68uH.

0 Rock Shao over 3 years ago in reply to Zack Liu

Expert 2945 points

Hi Zack,

Did you have the recommend IC for a micropower solution? The P2P LM2705 is better, thanks

0 Zack Liu over 3 years ago in reply to Rock Shao

TI__Mastermind 34201 points

Hi Rock,

LM27313 is P2P with LM2705. Please take a look at it.

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LM2705: The limit for the LM2705 FB pin upper resistance