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LM26484: LDO Vout

nirg
Prodigy 50 points
Part Number: LM26484
Other Parts Discussed in Thread: LM26480

Hi,

I want to use LM26484 in new design.

I need to know is there possibility to achive 1.8V as LDO output voltage, with AVDD = AVIN = PVIN = 3.3V conditions?

In DS there is only information, that Vout_max = 1.5V, but with PVIN supplied with 1.8V.

Thanks for your help.

Kamil

  • 0
    TI__Genius 9310 points
    Kamil,
    I have forwarded your question to the product specialist for this part. Thank you for using E2E.
  • 0
    TI__Mastermind 30280 points
    No, the LDO cannot generate voltages higher than 1.5V because the AVIN LDO circuitry is powered from 3.0V minimum and the LDO FET is specified as an NMOS type. This implies that the LM26484 LDO controller's gate drive is not a charge pump and the minimum overdrive voltage of the gate should be approximately 2*Vt threshold voltages. Therefore, it is unlikely that the LDO would be able to drive the maximum load if the output voltage is set to 1.8V

    Would you consider using the LM26480, which has 2x 300-mA integrated LDOs that can be externally configured to output a voltage from 1V to 3.5V?
  • 0 in reply to Brian Berner
    Prodigy 50 points
    Brian, thanks for your reply and that you showed me an alternative part.
    I think that LM26480 should fit into my design(I have only some doubts regarding max. output peak current which can be 1.45A @ 1V, but I need to investigate it deeper with DS).

    Only for our information:
    If we would need about <100mA from LM26484 LDO @1.8V, should it work?

    Thanks,
    Kamil
  • 0 in reply to nirg
    TI__Mastermind 30280 points

    Kamil,

    The LM26480 BUCK1 and BUCK2 are rated for 1.5A DC current, and I guarantee they will work with a current of 1.45A peak because on page 8 of the LM26480 datasheet there is a spec titled IPEAK for BUCK1 and BUCK2 which has a value of 2A typical and 2.4A max.

    I cannot guarantee the LDO of the LM26484 will work, because the performance is heavily dependent on the external FET and TI does not choose the FET used in the final design. You would need to test this performance but the LM26484 does not have an EVM available for purchase.