MPR031EPR2 Freescale Semiconductor, MPR031EPR2 Datasheet - Page 18

• Manufacturer Part Number: MPR031EPR2
• Description: IC CTLR TOUCH SENSOR 8-DFN
• Manufacturer: Freescale Semiconductor
• Type: Capacitiver

Specifications of MPR031EPR2

• Touch Panel Interface: 2-Wire
• Data Interface: I²C, Serial
• Data Rate/sampling Rate (sps, Bps): 400k
• Voltage - Supply: 1.71 V ~ 2.75 V
• Current - Supply: 43µA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-UDFN
• Output Type: Logic
• Interface: I²C
• Input Type: Logic
• Supply Voltage: 1.8 V
• Output Voltage: 0.5 V
• Supply Current: 8µA
• Ic Interface Type: I2C
• Supply Voltage Range: 1.71V To 2.75V
• Sensor Case Style: µDFN
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +85°C
• Interface Type: I2C
• Rohs Compliant: Yes
• For Use With: KITMPR03XEVM - KIT EVAL FOR MPR03XDEMOMPR031 - BOARD DEMO FOR MPR031 CTLR
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MPR031EPR2TR

MPR03X
18
Smaller amounts of change indicate increased sensitivity for the capacitance sensor. Some sample values are shown in
In the above cases, the capacitance is assumed to be in the middle of the range for specific settings. Within the capacitance
range the equation is nonlinear, thus the sensitivity is best with the lowest capacitance. This graph shows the sensitivity derivative
reading across the valid range of capacitances for a set I, T, and V
21 pF) and a nominal 1.8V supply the following graph is representative of this effect.
-0.5
-1.5
-2.5
-3.5
-4.5
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
-1
-2
-3
-4
-5
0
0.1
0
0
10
12
Sensitivity vs. Capacitance for V DD = 1.8 V and I =36 μA and T = .5 μS
500
Sensitivity vs. Midpoint Capacitance for V DD = 1.8 V
Table 11.
14
100
pF
10
16
dC/dADC @cmid (pF/1 ADC Count)
Minimum
Midpoint Capacitance (pF)
1000
Sensitivity (pF/ADC count)
18
Figure 23.
Figure 24.
C/ADC
Capacitance
-0.01953
-0.19531
20
DD
. For simple small electrodes (that are approximately
1500
22
24
2000
26
Maximum
28
Freescale Semiconductor
2500
30
Sensors
Table
11.