XTR110: Recommendation for SMD external transistor

Matthew Walton

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!

over 1 year ago

+1 Clemens Ladisch over 1 year ago

Guru 310880 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).

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

0 Matthew Walton over 1 year ago in reply to Clemens Ladisch

Prodigy 10 points

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

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XTR110: Recommendation for SMD external transistor