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MC33063A: Design Clarification & Components Ranges

Part Number: MC33063A

Hai Sir,

Based on Customer recommendation we are using MC33063A for voltage conversion.

End application- Controlling & Analog outputs driving.

Can you please give me the clarification about my queries posted below...

1) Designing Vin= 5V and Vout=  -12V, Iout= 100mA to 150mA  (Voltage-Inverting application)

 -> As per the Datasheet reference 9.2.1 Voltage-Inverting Converter Application , page no.9. Downloaded the Pspice model from TI, Simulated and Verified the Results as per the design.

->  Can we use this design for further process 

-> Here external components used Cin- 100uF, Cout- 1000uF, Ct- 1500pF . Can we use these capacitor values with Ceramic capacitors.

-> Inductor used L-88uH, If 88uH is not available in stock, What is the range of this inductor for Iout-100mA ?

-> Rsc- 0.24ohm used, What is the range of this resistor for Iout-100mA ?

2) Designing Vin= 5V and Vout=  12V, Iout= 500mA  (Step-Up converter application)

 -> As per the Datasheet reference 9.2.2 Step-Up Converter Application , page no.13. Downloaded the Pspice model from TI, Simulated and Verified the Results as per the design for Vin-5V & Vout-12V.

-> As per the Boost converter external components calculator we designed & simulated the 5V to 12V converter with below mentioned external components

 /cfs-file/__key/communityserver-discussions-components-files/196/1462.MC33063A-External-Components-Design_5F00_New.xlsx

-> Here external components used Cin- 100uF & 10uF, Cout- 100uF & 10uF, Ct- 1500pF . Can we use these capacitor values with Ceramic capacitors.

-> Inductor used L-12uH, If 12uH is not available in stock, What is the range of this inductor for Iout-500mA

-> Rsc- 0.1ohm used, What is the range of this resistor for Iout-500mA ? 

-> And also for Vout-12V the selected Resistors are R18-8.2k, R16- 953R. pls verify once

-> And also can we use this IC for 5V to 12V conversion with Iout-500mA to 1A current Range ? if not what is the Iout range for 5V to 12V boost conversion?

  • Hello Sandeep,

    Thanks for reaching out to us via e2e.

    I am a bit busy today, so I could not yet have a closer look at your questions.

    I will come back to you before the end of the week.

    Best regards,

    Harry

  • Sorry sir,

     I have accidentally  pressed "Resolved" button. But i have still queries regarding this thread.

    I am a bit busy today, so I could not yet have a closer look at your questions.

    ok sir

  • Hello Sandeep,

    I understand. And I am sorry to keep you waiting that long.
    I need to make myself familiar with this part, so it may take until the beginning of next week.

    Best regards,
    Harry

  • Hai sir,

    Is there any update regarding this query

  • Hello Sandeep,

    Finally I will find some time to look into your design.
    I am sorry for the long delay.

    Upfront I have a few questions:

    ->  Can we use this design for further process
    I do not really understand this question. Can you please explain?

    -> Here external components used Cin- 100uF, Cout- 1000uF, Ct- 1500pF . Can we use these capacitor values with Ceramic capacitors.
    How would you want to achieve 1000uF with ceramic capacitors?


    I will look into the questions about tolerances of the components now.

    Best regards,
    Harry

  • I do not really understand this question. Can you please explain?

    It means if the design is ok. can we go for production of this design.

    How would you want to achieve 1000uF with ceramic capacitors?

    Actually with 2 or three parallel capacitance. but now we are using the Electrolytic capacitors only.

    Can you please give clarity about the remaining queries as early as possible.

  • Hi Sandeep,

    I have some comments, which might be helpful in answering your questions:

    Q1) Using the PSpice Designs
    The simulation models are meant to be a reference for circuit design. They are designed to fulfill all device specifications and propose a great starting point for custom designs. However, before going into production with these exact values, I would recommend to check if the design fits with your desired parameters (e.g. input voltage range, output voltage, max. load, external components specs of inductor and diode, etc.).

    For additional reference, I would recommend to take a look at the reference designs provided on the product page.
    https://www.ti.com/product/MC33063A#design-development
    The given design show schematic that have been physically build and not just simulated, which might give further insights.

    Q2) Input/Output caps
    A common approach is to use a combination of both ceramic and electrolytic caps for a design. However, the given values and components are only recommendations. If the design performs best with only using ceramic caps, it is a valid option.

    Q3) indcutor selection
    The datasheet provides some formula on calculating the minimum inductance for each topology. I would recommend to run these calculations and select an inductor that fits the given specifications.
    This also counts for Rsc.

    When it comes to maximum input voltage ranges and output current, it is important to stay within the abs max ratings given in the datasheet of the device.

    Please let me know if there are additional questions.

    Best regards,
    Niklas

  • Thank you for your reply sir,

    I have one more query sir.

    I designed the Step up converter for 5V to 12V, iout-150mA as per the datasheet calculations.

    Can you please verify once & let me know if any modification to be done. And also can you please verify the R19-8.2k, R17-953R for 5V to 12V conversion are suitable or not

  • Hi Sandeep,

    Thanks for sending your design.
    All parameters and components seem to be within spec.
    I also run the feedback resistor calculations with R17 & R19 from my side as well and got a theoretical Vout of 12.00V, which is exactly what you are want to have. Therefore, I would say these resistors are indeed suitable.

    Please let me know if any additional questions come up.

    Best regards,
    Niklas