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TPS7A20: LDO recommendation for #1 3.3V to 0.9V/280mA and #2 3.3V to 1.8V/320mA

Shawn_Wang
Expert 3811 points
Part Number: TPS7A20
Other Parts Discussed in Thread: LP5912, TLV755P, TLV702, TLV743P, TLV740P, TPS62912

 Hi team

Could you help recommend the correct devices for the following applications?

  1. 3.3V to 0.9V/280mA, TA=65°C, PSRR @1khz>60dB
  2. 3.3V to 1.8V/320mA, TA=65°C, PSRR @1khz>60dB
  3. Cost-sensitive

Thank you.

  • 0
    TI__Expert 6560 points

    Hi Shawn,

    Are you looking for the devices to have fixed output voltage options within the ranges provided?

  • 0 in reply to Andres Sagredo
    TI__Expert 3811 points

    Hi

    Fixed and adjustable both are okay for my customer, and could you help give your recommendation?

  • 0 in reply to Shawn_Wang
    TI__Expert 6560 points

    Hi Shawn,

    For the first application (0.9V to 3.3V) the devices that have the best fit are TLV755P and LP5912, I placed a table to compare with TPS7A20 since it would be a great solution.

      TPS7A20 TLV755P LP5912
    Output Options Fixed Output Fixed Output Fixed Output
    Iout (Max) (A) 0.3 0.5 0.5
    Vin (Max) (V) 6 5.5 6.5
    Vin (Min) (V) 1.6 1.45 1.6
    Fixed Output Options (V) 0.9, 1.05, 1.2, 1.5, 1.8, 1.825, 1.85, 2.2, 2.4, 2.5, 2.7, 2.8, 2.85, 2.9, 3, 3.1, 3.2, 3.3, 3.6, 4, 4.2, 4.5, 5, 5.5 0.7, 0.9, 1, 1.1, 1.2, 1.5, 1.8, 1.85, 1.9, 2.5, 2.8, 2.9, 3, 3.3 0.9, 1, 1.1, 1.2, 1.5, 1.8, 2.5, 2.8, 3, 3.3, 5
    PSRR @ 1KHz (dB) 70 55 65
    Noise (uVrms) 7 60 12
    Accuracy (%) 1.5 1.5 3
    Vdo (Typ) (mV) 110 220 150
    Iq (Typ) (mA) 0.0065 0.025 0.03
    Package Type DSBGA, SOT-23, X2SON SOT-23, WSON, X2SON WSON

    For the second application some great picks would be TLV740P, TLV743P, and TLV702. Below is a table comparing these to TPS7A20 as well.

      TPS7A20 TLV740P TLV743P TLV702
    Output Options Fixed Output Fixed Output Fixed Output Fixed Output
    Iout (Max) (A) 0.3 0.3 0.3 0.3
    Vin (Max) (V) 6 5.5 5.5 5.5
    Vin (Min) (V) 1.6 1.4 1.4 2
    Fixed Output Options (V) 0.9, 1.05, 1.2, 1.5, 1.8, 1.825, 1.85, 2.2, 2.4, 2.5, 2.7, 2.8, 2.85, 2.9, 3, 3.1, 3.2, 3.3, 3.6, 4, 4.2, 4.5, 5, 5.5 1, 1.2, 1.8, 2.8, 3.3 1, 1.05, 1.1, 1.2, 1.5, 1.8, 2.5, 2.8, 2.85, 3, 3.3 1.2, 1.5, 1.8, 2.5, 2.8, 2.9, 3, 3.1, 3.3, 3.5, 3.6, 3.7, 4.3, 4.5, 4.75
    PSRR @ 1KHz (dB) 70 60 55 68
    Noise (uVrms) 7 65 120 48
    Accuracy (%) 1.5 1 1.4 2
    Vdo (Typ) (mV) 110 460 122 220
    Iq (Typ) (mA) 0.0065 0.05 0.034 0.03
    Package Type DSBGA, SOT-23, X2SON SOT-23, X2SON SOT-23, X2SON SOT-23, WSON
  • 0 in reply to Andres Sagredo
    TI__Expert 3811 points

    Hi Andres

    For TPS7A20, could you help chekc if it is working well for 3.3V to 0.9V/280mA, TA=65°C? I have the concern on the thermal performance.

  • 0 in reply to Shawn_Wang
    TI__Expert 6560 points

    Hey Shawn,

    For TPS7A20 at this ambient temperature it is important to keep your (Vin-Vout) difference small enough to make sure the foldback current circuit doesn't begin lowering your output current. For the lower Vout values you will want to use a lower value of Vin to keep the junction temperature (TJ) of the device within the limit of 150°C. Below is the formula to calculate the junction temperature for reference.

    I have below a table with the different values of Vin and Vout which will keep your TJ right below the limit given a constant current of 280mA and TA=65°C, divided by the different packages available.

    Note that the difference between input and output can be lowered to achieve a lower TJ.

    Vin(V) Vout(V) TJ(°C)
    DBV
    2.4 0.9 144.4801
    2.7 1.2 144.5923
    3.3 1.8 144.8169
    4 2.5 145.0788
    4.8 3.3 145.3782
    YCK
    2.3 0.9 144.8752
    2.6 1.2 144.9961
    3.2 1.8 145.2378
    3.9 2.5 145.5197
    4.7 3.3 145.842
    DQN
    2.6 0.9 144.9273
    2.9 1.2 145.027
    3.5 1.8 145.2263
    4.2 2.5 145.4588
    5 3.3 145.7246
  • 0 in reply to Andres Sagredo
    TI__Expert 3811 points

    Hi Andres

    Thanks for your information.

    It seems LDO is not a good option for 3.3V to 0.9V/280mA, TA=65°C. I am considering to promote TPS62912/3 to my customer. Thank you again.