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MC34063A: [MC34063ADR] Request circuit review

Part Number: MC34063A

Hi, TI support team

The customer has configured the circuit below, and we request you to review it.

When designing, the condition is as follows.

-Vin=5V

-Vout=30V

- Iout=(typical)14mA, (Max.) 56mA

When designing under the above conditions, please review the problems in the circuit configured below or the capacitance value of each part.

In particular, please review whether the values of R253 (Rsc), inductor, and Co are appropriate and what values are recommended.

Thanks.

Regards,

MJ

  • Hi MJ,

    Thank you for reaching out, regarding your query according to the application section of the datasheet here https://www.ti.com/lit/ds/symlink/mc34063a.pdf?ts=1675692125433&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FMC34063A the Lmin should be bigger than what you have in your design, but this you can calculate using the formulas given there. From my calculation the minimum inductance should be around 210-250 uH for your design specifications. As for the Cout it depends on the amount of voltage ripple at the output. 

    For the Rsc it should be around 0.72 - 0.68 ohms according to the calculation table in the datasheet section 9.2.2.2. I would suggest to use the formulas there and compare with the values in your design.

    My calculation are based on the minimum Vin taken as 5V.

    Hope this helps.

    BR,

    Haroon

  • Hello MJ

    I have not seen an update from you for the last 18 days, so I assume the questions are answered and the issue is solved.
    I close this thread now. If there is still something open, please reply and the thread will get opened again.
    If you have any other question or of the thread has been locked, please open a new one.

    Clicking the Resolved Button also helps us to maintain this forum.

    Best regards,
    Harry