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TPSM828303: Suitable for ADC input Supply

Haritha Munnangi
Intellectual 280 points
Part Number: TPSM828303
Other Parts Discussed in Thread: ADC12DL2500

Tool/software:

Hi Team,

For ADC (P/N: ADC12DL2500), we are planning to give input supply as mentioned below.

Main supply 12V to 5V, from 5V to 2.2V and from 2.2V to 1.9V (VA19),

Main supply 12V to 5V, from 5V to 1.5V and from 1.5V to 1.1V (VA11, VD11).

For generating 5V to 2.2V and 5V to 1.5V we planning to use P/N: TPSM828303ARDSR.

Will be it there any issue or can we use this above-mentioned part for our design??

Thanks in advance,

Regards,

Haritha.

  • 0
    TI__Mastermind 22150 points

    Hello Haritha,

    thanks for reaching out in E2E.

    The TPSM828303ARDSR is fulfilling the mentioned voltage range requirements and is able to deliver the required supply current. So from that perspective the TPSM828303ARDSR is suitable.

    Although the TPSM828303ARDSR is a high performance device it is unavoidable that switch regulators have some small output voltage ripple (see figure 8-34 and 8-35 in the datasheet).

    In section 7.4 of the ADC12DL2500 datasheet it is recommended to add an LDO or a second stage ripple filter after the TPSM828303ARDSR, as depicted in figure 7-10 and 7-11.

    This application note is providing additional details for second stage filter design: "Using the Filters with the DC/DC Step-Down Converter". I would like to highlight, that such filters should be damped as described in section 4 of this application note, to avoid resonance issues.

    Please be aware that for lower load the TPSM828303ARDSR is automatically transitioning into Power Safe Mode (PSM) as described in section 7.3.2 of the datasheet. This means the switching frequency and also the output voltage ripple frequency is reduced a lot, which might be an issue for the second stage filter design. For that case it would be possible to force the device not to enter the PSM by setting the MODE pin to high. This forced PWM operation comes with a tradeoff in efficiency.

    Best regards,

    Andreas.

  • 0 in reply to Andreas Mueller
    Intellectual 280 points

    Hi Andreas,

    Thanks for the quick response.

    Yes we are using second stage LDO from 2.2V to 1.9V and 1.5V to 1.1V in the design.

    In ADC reference design as shown below, For U18 and U19 they are using 3A rated IC, but instead of that can we use 2A IC??

     

    Regards

    Haitha

  • 0
    TI__Mastermind 22150 points

    Hello Haitha,

    thanks for your feedback.

    I think the 2A version TPSM828302 would be sufficient.

    Best regards,

    Andreas.