• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 64 subscribers
  • Views 1021 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS3700-Q1. Sheet 15, Figure 20. What's the best resistor or Pot for Low TCR?

Phil Blake
Prodigy 20 points
Other Parts Discussed in Thread: TPS3700-Q1

Because of the very odd values of resistance required for R1 and R2 in my application circuit, I am going to require low TCR potentiometers. Might anyone have a suitable pot for a temperature range of 25C to 50C? Thanks in advance.

  • 0
    TI__Guru 71536 points

    Hi Phil,

      I moved this to the Supervisor Forum.  What values do you have for R1/R2?

    ~Leonard

  • 0 in reply to LeonardEllis
    Prodigy 20 points

    Thanks, Leonard.  My R1 and R2 are quite large. R1 = 420k, R2= 4.5k.  For another detector I am using in the same circuit, R1=128k and R2=15.5k.

    One thing that I have noticed in PSpice, is that I can vary R1 and R2 over quite a range, and the window detector keeps on working. For example, I can vary R1 = 420k between 435k to 340k and the circuit still works.  I hope I'm not misunderstanding something.

    Phil

  • 0 in reply to Phil Blake
    TI__Guru 55940 points

    Hi Phil,

    TPS3700-Q1 uses the Resistor divider ratios to set the over and under voltage thresholds for the application.  Please refer to the design procedure as described in section 9.2.2 of the datasheet for the proper method of setting resistor dividers.

    We would recommend that you contact a resistor/pot manufacturer for information regarding the temperature coefficient of resistors.

    Very Respectfully,

    Ryan