MPR121

Sensors

Freescale Semiconductor

25

Figure 23. Average Supply Current

The output data is the Filtered Data High and Low is the data coming out of the second stage filter. This means that the

response time of the output is the SFI times the ESI. This usually results in 16 ms and 4 iterations being used to get 64 ms

response time while still optimizing the power consumption. At each 64 ms, a decision would be made regarding touch by com-

paring the Baseline with the filtered data output, resulting in a a worst case of the full 64 ms plus half the previous cycle, equalling

96 ms.

SAMPLE RATE (ms)

1

10

29

μA

17

μA

100

400

300

200

2

4

8

16

32

64

128

102

μA

54

μA

393

μA

199

μA

11

μA

8

μA