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XTR110: Recommendation for SMD external transistor

Matthew Walton
Prodigy 10 points
Part Number: XTR110

Hi all. I am planning on using the XTR110 as a simple 0-10V to 4-20mA converter, and would like to use a surface-mount external transistor. The recommended transistors in the datasheet are all through-hole, and most of them seem to be obsolete.

Apart from ensuring Vds is greater than my supply voltage, and Pd is high enough, are there any other specs that I should be looking at for the PMOS? Rds On? Vgs th?

The supply voltage will be 28VDC.

Would both the of the following be acceptable?

  • Diodes Incorporated DMP10H400SK3
  • Vishay Siliconix SUD09P10-195

Thanks!

  • +1
    Guru 281330 points

    The transistor is not integrated only because it needs to dissipate power. So the TO-252 package of your choices is a good idea. (28 V × 20 mA = 0.56 W, which isn't too bad.)

    You have to check the gate-to-source breakdown voltage (see p. 7).

    RDS(on) does not matter because the transistor will be regulated to a larger resistance, with the gate near VGS(th).
    VGS(th) does not really matter; your choices have thresholds similar to those of the datasheet recommendations.

  • 0 in reply to Clemens Ladisch
    Prodigy 10 points

    Ah gotcha, thanks! Both of the transistors I linked have a VGS of 20V, so I just need to add the 12V Zener, if I am reading the datasheet correctly.