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LM3488Q-Q1: LM3488's Various Characteristics

Part Number: LM3488Q-Q1
Other Parts Discussed in Thread: LM3488

Hi, team.

In selecting this IC, I would like to investigate the fluctuation rate of the feedback voltage under the following conditions, is it possible?

Condition: Switching frequency 100kHz

Vin = 24V (± 10% or ± 5%)

Operating ambient temperature -10℃~60℃

As for data, I would like if there is temperature characteristic and Vin characteristic of VFB.

Could you help us?

Best regards,

Masumi Sekiguchi

  • Sorry for the delay: will answer you tomorrow.
  • Thank you for contacting me.
    I am waiting.
  • Thank you for your interest in the LM3488. I think you mean the VFB reference voltage stability, right? The datasheet gives the tolerance of the FB reference voltage over the temperature range from -40C to +125C: 1.24Vmin to 1.28Vmax. For your reduced temperature range, the reference voltage will be smaller. However, we do not have the data just for your -10C to +60C range. The input voltage barely affect the reference voltage: 0.001%/V. Switching frequency has no effects on the reference voltage.

    If you mean the FB pin voltage it self, it is basically proportional to the output rail voltage scaled down by a resistor divider. It equals the reference voltage when the circuit achieves output regulation. When the output rail fluctuates, the FB pin voltage will follow, just on a smaller scale determined by the resistor divider.

    If this answers your question, please reply by clicking "This resolved my issue" button.


    Thanks,
    Youhao Xi, System and Applications Engineering, APP-BMC-BCS, TI
  • That's right.
    What I care about is the accuracy of the internal reference voltage.

    Can't you be to answer from the "min/max value" in the range of -10℃~60℃, too?
    (I’m OK, even for answers of typical values.)

    Best regards,
    Masumi Sekiguchi
  • Let me check with our product engineer to see if there are such data available.
  • Thank you for contacting.
    Please check.
  • Sorry for the delay. I just got back from our product engineer and he had done a lot of search. Unfortunately the data that you requested are not available. We believe the tolerance will be smaller in your narrow temperature range but we do not now how small it could be. Please use the limits over -40C to +125C for the worst case considerations.