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LM74700-Q1: Why is output capacitor needed?

Part Number: LM74700-Q1

Hi team, 

LM74700-Q1 datasheet says "The output capacitor COUT is recommended to protect the immediate output voltage collapse as a result of line disturbance." and "COUT: minimum 100 nF of output capacitance" which are related to "Figure 10-1. Typical Application Circuit".

1. Does "the immediate output voltage collapse as a result of line disturbance" cause fault operation of LM74700-Q1?

2. Or is output capacitor is just for "output load or voltage regulator in figure 10-1"?
    Meaning that LM74700-Q1 operate without fault due to "the immediate output voltage collapse as a result of line disturbance", is it correct?


  • Hi Ochi,

    The main purpose of recommending a capacitance at the output is for decoupling purpose. Without a decupling cap, any noise on the output load will be immediately affect the LM74700 gate control either by turning it OFF or by enhancing the gate which may not be acceptable. So, a minimum of 100 nF is recommended at the output. 

    Based on your application you can choose to use a larger output cap and the value of the cap required is completely based on your system requirements. 

  • Hi team, 

    Thank you so much.

    I understood that LM74700-Q1 monitor anode to cathode or source to drain voltage to control gate drive, which needs output noise reduction by output capacitor.