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XTR116: Incorrect reference voltage and malfunctioning 4-20mA output/driver.

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Part Number: XTR116

Hello, we created an 8 channel 4-20mA output/driver based off the XTR116. We are experiencing three problems:

1. The datasheet clearly states that the XTR116 has a VREF of 4.096 volts. The chips we received are correctly labeled as XTR116, but they are outputting 2.5 volts and not 4.096.

2. No matter what current we provide on the IIN pin, we get roughly 40mA on the current loop, it doesn't change. We have a digital-to-analog converter providing voltages/currents to the XTR116 to control this.

3. We are using the VREF off the channel 1's XTR116 for the digital-to-analog converters reference voltage. If we don't have anything hooked up to this current loop, the XTR116 no longer outputs a voltage on VREF... it becomes zero.... which causes all of the other 7 channels to fail.

Here is the circuit schematic showing the 8 channel 4-20mA drivers, the digital-to-analog converter for setting IIN, and the power supply. The idea is that any device that receives a 4-20mA signal can just hook up to 2 of the 4 terminals labeled as ISOLATED_POWER, and ISOLATED_GND. The power supply is already tied into the current loop:

Any help or advice on these 3 problems would be greatly appreciated, as we already have PCB's of these made, thanks!