SLAS942E November 2015 – December 2019 MSP430FR2532 , MSP430FR2533 , MSP430FR2632 , MSP430FR2633
PRODUCTION DATA.
To show sensitivity, in terms of farads, the internal reference capacitor is used as the change in capacitance. In the mutual-capacitance case, the 0.1-pF capacitor is used. In the self-capacitance case, the 1-pF reference capacitor is used. For simplicity, the results for only button 1 on both the CAPTIVATE-PHONE and CAPTIVATE-BSWP panels are reported in Table 7-1.
CONVERSION COUNT | CONVERSION GAIN | CAPTIVATE-PHONE BUTTON 1 | CAPTIVATE-BSWP BUTTON 1 | ||
---|---|---|---|---|---|
CONVERSION TIME (µs) | COUNTS FOR 0.1-pF CHANGE | CONVERSION TIME (µs) | COUNTS FOR 1-pF CHANGE | ||
100 | 100 | 25 | 6 | 50 | 8 |
200 | 200 | 50 | 10 | 100 | 16 |
200 | 100 | 50 | 21 | 100 | 31 |
800 | 400 | 200 | 70 | 400 | 112 |
800 | 200 | 200 | 140 | 400 | 202 |
800 | 100 | 200 | 257 | 400 | 333 |
An alternative measure in sensitivity is the ability to resolve capacitance change over a wide range of base capacitance. Table 7-2 shows example conversion times (for a self-mode measurement of discrete capacitors) that can be used to achieve the desired resolution for a given parasitic load capacitance.
CAPACITANCE, Cp (pF)(1) | CONVERSION COUNT/GAIN | CONVERSION TIME (µs) | COUNTS FOR 0.130-pF CHANGE | COUNTS FOR 0.260-pF CHANGE | COUNTS FOR 0.520-pF CHANGE |
---|---|---|---|---|---|
23 | 400/100 | 200 | 10 | 23 | 35 |
50 | 550/100 | 275 | 11 | 24 | 37 |
78 | 650/100 | 325 | 11 | 23 | 36 |
150 | 850/100 | 425 | 11 | 22 | 35 |
150(2) | 1200/200 | 600 | 11 | 23 | 37 |
200(2) | 1200/150 | 600 | 13 | 26 | 41 |