I'm working on an altimeter that reads the MPX4115 or MPX6115 pressure into the ADS1100 AD converter.
Has anyone here tried to do this?
My questions:
1. Did you avoid using an opamp to resolve the different voltage ranges between the two units? The ADS1100 is low impedance input so a classic resistor voltage divider seems unworkable.
2. Motorola Applications Note AN1646 suggests a low pass RC filter consisting of a 750 ohm resistor bypassed with a 0.33uf cap for the MPX4115 output. The MPX6115 manual suggests bypassing the output with a 47pf cap and a 51 kohm resistor, both to ground. Why the two different output schemes?
Has anyone here tried to do this?
My questions:
1. Did you avoid using an opamp to resolve the different voltage ranges between the two units? The ADS1100 is low impedance input so a classic resistor voltage divider seems unworkable.
2. Motorola Applications Note AN1646 suggests a low pass RC filter consisting of a 750 ohm resistor bypassed with a 0.33uf cap for the MPX4115 output. The MPX6115 manual suggests bypassing the output with a 47pf cap and a 51 kohm resistor, both to ground. Why the two different output schemes?