Other Parts Discussed in Thread: ADS1220, , OPA391, TLV9001, ADS114S06, ADS124S06
can you provide a solution for customer request I have received. The customer want to measure the TMR resistor chain and the RTD with the same ADC. Can you provide the best fitting ADC for this and a schematic how to connect the TMR Sensor to the ADC? The ADC should be connect to an MCU like MSPM0 via SPI or I2C. The sample rate can be very low. <100 SPS.
- TMR with open-drain output
- Switch between resistors and change it like a rheostat / potentiometer
- For operation 1.8-5Volt and approx. 1.5µA are needed.
- Problem: Open drain switches to GND - thus rheostat is connected to GND on one side
-> influence BIAS resistance at load by current consumption TMR
TMR are available with simple "switching function" and also with COS/SIN output or analog output.
Here a simple switching function is used: TMR1340 or comparable model of a competitor.