MSP430F6736: MSP430F6736 internal 24 bit ADC

What pressure sensor?

The one I use is a bridge that would requires a bipolar input which the MCU does not have, or has a common mode voltage too high for the MCU.

Below are the specification of two sensor - 1. normal piezo resistive and 2. differential pressure sensor. For Differential pressure sensor- Bridge resistance 10kΩ@25°C Power supply 3…8VDC (Recommend 4.5…5.5VDC) Response time 10ms Long-term stability ≤0.03%FS/Yeas Output mV signal Operating temperature -40…+85°C Body material 316SS Piezoresistive pressure sensor- Zero output ±2 mV / VS = 1.5 mA Full scale output 90 mV(typ.) , 150 mV(max.) / VS = 1.5 mA Excitation 1 mA~2 mA Bridge resistance 2~8 kΩ Insulation resistance 100 MΩ@100VDC Kindly let me know whether we can directly give the output of these sensor to internal 24 bit ADC (sigma-delta) or not?

What is your supply voltage to the sensor? What is the supply voltage to the MCU?

If you use a 5 V supply for the sensor, the common mode voltage is probably 2.5 V, which is fine for a 3.3 V supply to the MCU, but not fine for 1.8 V.

Hi

Yes we will use +5V excitation voltage for sensor and +3.3V Vcc for microcontroller. So no any problem related to voltage.

Kindly let me confirm:

1. Can we directly give the output of these sensor to internal 24 bit ADC (sigma-delta) of microcontroller MSP430F6736?

2. Is there any need of external signal conditioning?

3. Can we get pressure transmitter response time <10ms using this internal 24bit ADC of controller?

4. We want to use HART modem DAC8740 with the design, kindly guide how to isolate the HART modem.

1 &2 It should be fine, it does not look like you need signal conditioning. However, a buffer might allow for more speed, depending on the internal impedance of the sensor.

Someone else will have to answer 3&4