• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 3 answers
  • Subscribers 63 subscribers
  • Views 305 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TPS53315: Schematics Review

Shifali N
Expert 2040 points
Part Number: TPS53315

Hi,

I am using TPS53315RGFT in my design. I would like to have my design review by an expert and provide their feedbacks. I am using TPS53315 to provide power to SATA devices.

Vin=12V

Vout=5V

Iout=7A

I have attached my schematics below:

TI_Regulator_review.pdf

  • 0
    TI__Genius 11315 points

    4073.TI_Regulator_review.pdf

    Here is the schematic with my feedback.

    Let me know if you have any further questions. Make sure to follow the layout recommendation on the datasheet. 

    Thanks,
    Caleb

  • 0 in reply to Caleb Perez
    Expert 2040 points

    Hi Caleb,

    Thankyou for sharing your feedbacks. I have few queries which are as below.

    1. I calculated the RTRIP using the formula 13 mentioned in datasheet. I have considered L=3uH, fsw=400kHz,IOCP=15A. Depending on the calculation 77.7k looks like more appropriate value. RTRIP value of 68.1K gives IOCP of 13.37A.

    2. Calculated R1 value using the formula 18 present in datasheet. R1=73.2K gives me Vout of 4.9V and R1=69.8K gives me Vout of 4.7V. Hence I have considered R1=73.2K.

    3.  Also in application circuit diagram Figure 22,they have connected RF,VFB and trip to AGND. But AGND they have connected to PGND. So whether its okay to connected these pins to PGND.

    Thanks

  • 0 in reply to Shifali N
    TI__Genius 16660 points

    1.   The Rtrip of 77.7k is okay.  A standard 1% resistor of 78.7kOhm or 76.8kOhm may cost less. 

    2.  The RCC circuit injects ripple and will offset the output voltage,  If you change R118, C302 orC299, you may need to adjust the 73.2k. 

    Using eq 18 you should calculate 4.992V with 73.2kOhm without the RCC circuit.   With 69.8k it will be 4.79V.

    If you include the RCC injection Vinj_out  from 17,  I think caleb's is closer to 5V

    3.     The  R2, R8 and R4 are sensitive to noise and should be connected to AGND.    Then AGND should connect to one location on PGND.   Some designers use 0 ohm resistors to define the location where AGND connect to PGND to prevent the autopour of the pcb software connecting anywhere. 

    See Figure 38 for pcb layout example

  • 0 in reply to David_Daniels
    Expert 2040 points

    Hi David,

    1. To calculate Vinj_out from Equation 17, may I know Whether Vinj_out was derived using Equation 16. If equation 16 was used I would like to know what was the IND(ripple) ,ESR and Cout values used to calculate Vinj_Out.

    Also whether I have to change R118,C302 and C299 values? Or can I retain the same values.

    2. Also I would like to know to which pin of IC should RF, TRIP, Mode and VFB should be connected. Pin 1 or Pin4 of IC.

  • 0 in reply to Shifali N
    TI__Genius 11315 points

    David will be out of office for Christmas and New Years holiday. 

    To answer your questions, I recommend following the WEBENCH designer to meet the goals of your design. 

    For question 2, please connect RF, TRIP, MODE, and VFB to pin 1. Pin 1 should be the analog ground plane.