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TPS704: TPS70402PWP

Veena Kajava
Prodigy 40 points
Part Number: TPS704

We are using TPS70402PWP regulator in one of our design. I have uploaded the schematic, kindly verify the schematic and let me know if any changes are required.

  • 0
    TI__Genius 12345 points

    Hi Veena, 

    Thank you for reaching out and sharing this with us. 

    I am having trouble reading some of the values, can you share the schematic in a different format. You can also email it to me, and I will review it. 

    Best, 

    Edgar Acosta

  • 0 in reply to Edgar Acosta1
    Prodigy 40 points

    TPS70402PWP.pdf

    Kindly review and let me know if any changes are required.

  • 0 in reply to Veena Kajava
    TI__Genius 12345 points

    Hi Veena, 

    I revised the Schematic, and here are some of my comments: 

    For the output capacitor, make sure that the ESR is within the recommended values, 50 mΩ and 800 mΩ for Vout1 and a 22uF cap, and 50 mΩ and 2 Ω for Vout2 and the 47uF. There is a region of stability shown in page 21 of the DS.

    I see that the Second channel is set to Vout2=5V, however, the input supply is already 5V -some drop due to the LC filter. Having said that, Vout2 will follow the input voltage at Vin2-Vdo, please make sure that this is intended or make sure that Vin2 is greater than 5V+Vdo. 

    Best, 

    Edgar Acosta

  • 0 in reply to Edgar Acosta1
    Prodigy 40 points

    Is it possible for me to get 5.5V at the Vout2 by giving 5V input to the Vin2? Datasheet says adjustable output can be from 1.22V to 5.5V.

  • 0 in reply to Veena Kajava
    TI__Genius 12345 points

    Hi Veena, 

    Unfortunately, it is not possible.

    Linear regulators are more of a step down, where you regulate from a higher Vin to a lower Vout. Therefore, Vin needs to be higher than your set Vout.

    You will find that data sheets describe drop out voltage, which is commonly known as Headroom voltage. When looking at our EC tables, you will also find a condition like "VIN = VOUT(nom) + 1 V", and also you will commonly see Vin= Vout(nom) + Vdo, where Vdo is the dropout voltage and normally it is the minimum voltage difference needed for the LDO to regulate. 

    From the TPS704 DS: 

    The majority of the EC table specs use VIN = VOUT(nom) + 1 V, unless otherwise noted. Therefore, the device is capable of regulating 5.5V, but you would need a higher voltage, in this case probably Vin=6V would be the best level of operation. 

    Best, 

    Edgar Acosta

  • +1 in reply to Edgar Acosta1
    Prodigy 40 points

    Thank you so much.