LTM8074 RT pin

Hi

I'm DFAE in Japan. Our customer is evaluating LTM8074 and asked a question about RT pin to resistor.

According to Page10 of LTM8074 DS, minimize capacitance at this pin. In order to get closer to the recommended resistor value listed in DS, when connecting the E24 series resistors in series than when connecting them in parallel, the capacitance component will be smaller, so I would recommend series connection. However, since the frequency characteristic of the resistor is flat up to about 10MHz, I feel that there is no need to be so nervous about the capacitance component of the resistor. What do you think?

Regards,

Hiroyuki

  • 0
    •  Analog Employees 
    on Mar 10, 2020 4:31 PM

    Hi Hiroyuki,

    You don't need to worry about the capacitance of the resistor.  The note about reducing capacitance is to warn the user against using long traces and making too many connections to the RT pin in the layout which may cause instability on the pin.  Attempting to probe the pin with a 10pF probe can cause instability and inaccurate measurements in some cases as well.

    Regards,

    Tim Kozono