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TPS27081A: TPS27081A crossing part

Jeff YANG
Mastermind 6740 points
Part Number: TPS27081A
Other Parts Discussed in Thread: TPS27082L,

Hi,

We are trying to use TPS27082L as an alternative source for the TPS27081A.

In the characteristic and peripheral circuit of components portion, does there any concerns we need to pay attention to?

Do we can install TPS27082L on the location U15 directly and keep the peripheral circuit setting?

The TPS27082L internal block diagram as following table's right side.

If we want to achieve maximize the ON-state Vgs-q1 and minimizes Vin to Vout voltage drop.

The better R1 value is 10 times as R2, Right? 

So, base on our peripheral circuit of U15

TPS27081A equation:

Vgs-q1 = -3.3V*(100K / (100K+0)) = -3.3V, Rds(on) around < 44m ohm

TPS27082L equation:

Vgs-q1 = -3.3V*(100K / (100K+12.5K)) = -2.93V, Rds(on) around > 44m ohm

Thanks!

Jeff

  • 0
    TI__Genius 15725 points

    Hi Jeff,

    With regards to placing the TPS27081L in the circuit originally made for the TPS27081A, 

    • The only changes I would recommend to be made to the original schematic is changing R1 > 125kΩ and select a closest standard valued capacitor C1 to put between Vout and R1/C1 as shown in the following schematic and after selecting a C1 that satisfies the following equation: 

    • The ON pulldown R109 should stay to ensure ON/OFF is not left floating.

    Best Regards, 

    Elizabeth