• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 278 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LP38798: LP38500ATJ-ADJ/NOPB

Gajendiran A
Prodigy 225 points
Part Number: LP38798
Other Parts Discussed in Thread: TPS737, TPS7A90,

Hello,

We have requirement of LDO in our design. The design specification is input voltage is 5V(4.8V-5.2V) and output is 3.3V/0.232A(Ambient  temperature range is :-40deg to 105deg) .During the maximum load driven from the LDO. The output voltage should not be below 3.135V.

We have simulated the LP38500ATJ-ADJ/NOPB LDO in  WEBENCH® Power Designer. But the output voltage is always 0V. Please refer the attached image. And let us know the option to get output wave in the simulation.

It will be helpful if you suggest another LDOs part number with above specification.

Regards,

Gajendiran A

  • 0
    TI__Genius 14245 points

    Hi Gajendiran,

    The Webench tool is not supported for new LDOs so its not something we use and I'm not 100% sure why it may not be working but did you try short EN to Vin? I know the device has an internal pull up but perhaps the old Webench model doesn't capture that function properly.  

    As for other part suggestions the tough part is the high ambient temperature but TPS737 or TPS7A90 may also be worth considering (see spec comparison table below). For your max ambient temperature and power dissipation you need a part with a Rja (junction to ambient thermal resistance) of approximately 50C/W or less depending on your PCB layout. Note, a very good PCB layout can reduce the JEDEC standard Rja shown in the datasheet by 30%-50% as shown in our App Note which measured the Rja of three different packages on 5 PCB different layouts to see how they compared to the JEDEC standard. 

      LP38798 TPS737 TPS7A90
    AEC Q100 NO NO NO
    Output Options Adjustable Output Adjustable Output, Fixed Output Adjustable Output
    Iout (Max) (A) 0.8 1 0.5
    Vin (Max) (V) 20 5.5 6.5
    Vin (Min) (V) 3 2.2 1.4
    Vout (Max) (V) 19.8 5.4 5.7
    Vout (Min) (V) 1.2 1.2 0.8
    Fixed Output Options (V) - 1.8, 2.5, 3, 3.3, 3.4 -
    Enable YES YES YES
    Power Good NO NO YES
    Output Capacitor Type Ceramic, Non-Ceramic Ceramic Ceramic
    PSRR @ 100KHz (dB) 65 33 48
    Noise (uVrms) 5 48 4.7
    Accuracy (%) 2 3 1
    Vdo (Typ) (mV) 200 130 75
    Iq (Typ) (mA) 1.4 0.4 2.1
    Thermal Resistance θJA (°C/W) 35 50 57
    Min Package Area (mm2) 16 4 6.25
    Package Type WSON SON, SOT-223, WSON SON