XTR115: Schematic review

Atsushi Takahashi

Expert 1405 points

Part Number: XTR115
Other Parts Discussed in Thread: XTR111

Tool/software:

Hi Team,

Could you review the attached schematic?

My customer designed it according to the data sheet, however, it is not working properly.

The output is terminated at 250 Ω and the voltage at both ends is measured, but even if the input current is changed from 4 to 20 mA while keeping the output at about 3 V, there is no change.

Best Regards,

6 months ago

0 Clemens Ladisch 6 months ago

Guru 316440 points

The XTR115 is designed for a 2-wire system. In such a system, the entire transmitter is powered from the loop current, and the transmitter's ground must be floating.

Where does +5VA_DA come from? Is AGND_IDA used by both transmitter and receiver?

0 Atsushi Takahashi 6 months ago in reply to Clemens Ladisch

Expert 1405 points

Hi Clemens-san,

+5VA_DA and GND come from the system power supply.

Is this a problem?

0 Ashley Kang 6 months ago in reply to Atsushi Takahashi

TI__Genius 15250 points

Hi Takahashi-san,

Could you clarify what you are using VREG and VREF for? These are voltage output pins.

Regards,
Ashley

0 Clemens Ladisch 6 months ago in reply to Atsushi Takahashi

Guru 316440 points

You must not connect IRET to the system ground. With separate power supply connections, you have a 3-wire system and must use a 3-wire transmitter like the XTR111.

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XTR115: Schematic review