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TL1431-SP: Stability - Output Capacitance requirement ?

Sean McCarthy
Prodigy 160 points
Part Number: TL1431-SP
Other Parts Discussed in Thread: TL1431, TL431,

I will be using SMD # 5962R9962001VHA.  My application is the following:

Power Supply input 3.3V (+/-4% tolerance), TL1431 configured for 3V output.

The TL431.xlsx tool calculator suggest R1 = 61.9-Ohms, R2 = 1.24-K and R3 = 6.19-K and an output capacitance to maintain stability - either less than 6200-pF or greater than 3.3-uF.

I will use the 3V reference to power TI, ADC (5962R0722701VZA) and DAC (5962R0722602VZA)...powering VA & VD pins of each with the decoupling as indicated in the DS (VA with 0.1-uF and VD with RCC from VA).  I will have another 0.5-mA of loading.  Note, both the ADC and DAC will be monitoring and setting DC levels no dynamic requirements).

Question:

The output capacitor requirement indicated in the excel tool calculator is not discussed in the datasheet.  As such I am not confident on how serious this capacitor will be in my design ?

I have limited real estate and prefer to have further feedback on the concern for stability in regard to my application.  Can you provide further feedback on this.

Regards,

Sean

regards,

Sean

  • 0
    TI__Mastermind 28845 points

    Hey Sean,

    The reason the TL1431-SP doesn't mention the capacitor is because the capacitor is needed for a specific implementation of the device.

    There are many different ways the device can be configured and the calculator is specific to yours.

    I would highly suggest using the capacitor for stability.

    Thanks,

    Daniel