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LM74722-Q1: LM74722QDRRRQ1

Ilan Hazi
Prodigy 60 points
Part Number: LM74722-Q1
Other Parts Discussed in Thread: LM74800-Q1,

Hi,

Today I'm using the LM74800-Q1/LM74801-Q1 in my product.

Since those components aren't in the stock I want to replace them with the LM74722-Q1.

Since the  LM74800-Q1/LM74801-Q1 and LM74722-Q1 almost pin to pin compatible. does Pin 9(N.C) on LM74722-Q1 be connected to VOUT?

  • 0
    TI__Guru 57737 points

    Hi Ilan,

    LM74722-Q1 has a boost based gate drive circuit compared to that of a charge pump in Lm7480x-Q1.

    The integrated boost controller in LM74722-Q1 needs an inductor,L1 to operate as shown in figure below. In case you want to co-layout LM74722-Q1 with LM7480x-Q1, then you will need to have a placeholder for resistor/ inductor to change between LM7480x-Q1/ LM74722-Q1.

    Is your layout already done ? If yes, do you have a provision for R1 as shown in image below for LM7480x-Q1 ?

  • 0 in reply to Praveen GD
    TI__Guru 57737 points

    Hi Ilan,

    to answer your question, Pin 9(N.C) of LM74722-Q1 can be connected to VOUT as the N.C pin is not connected to the die internally. 

  • 0 in reply to Praveen GD
    Prodigy 60 points

    Hi Praveen,

    Thanks for your answer, will do layout and insert the R1 as optional to L1.

    Does the LM74722-Q1 is prefer than LM7480x-Q1?

  • 0 in reply to Ilan Hazi
    TI__Guru 57737 points

    Hi Ilan,

    LM774722-Q1 has boost converter based gate drive circuit compared to that of Charge pump based gate drive in LM74800-Q1.  Boost converter based architecture has advantages of very low Iq and Higher boost load capacity.

    Higher boost load capacity enables Active rectification for higher frequencies (200 kHz) even for high gate capacitance/ parallel  Mosfets.

     

    LM74810-Q1

    LM74722-Q1

    Quiescent Current, I(Q) Max

    480 µA

    35 µA

    Charge Pump source current / Boost load capacity

    3.8 mA

    29 mA

    tGATE_ON(DLY)

    1.6 µs

    1.25 µs

    If the above features are important for your system, you can prefer using LM74722-Q1 over LM74800-Q1. Otherwise the performance of both the devices is similar

  • 0 in reply to Praveen GD
    Prodigy 60 points

    Hi Praveen,

    Thanks for your answers.