MAX1441
Automotive, Two-Channel Proximity and
Touch Sensor
5
Typical Operating Characteristics (continued)
(VBATT = 14V, VAA = VDD = 3.4V, TA = +25NC, unless otherwise noted.)
CAPACITANCE ERROR
vs. INTERFERENCE FREQUENCY OFFSET
MAX1441
toc10
INTERFERENCE FREQUENCY OFFSET (kHz)
CAPACITANCE
ERROR
(%
FULL
SCALE)
450
400
350
300
250
200
150
0
10
20
30
40
50
60
-10
100
500
10pF RANGE,
CO_ = 8,
300kHz
EXCITATION
FREQUENCY,
500mVP-P
INTERFERENCE
FREQUENCY
CAPACITANCE ERROR
vs. EXCITATION BANDWIDTH
(WITH IN-BAND INTERFERENCE)
MAX1441
toc11
EXCITATION BANDWIDTH (kHz)
CAPACITANCE
ERROR
(%
FULL
SCALE)
150
100
50
0
10
20
30
40
50
60
-10
0
200
10pF RANGE,
CO_ = 8,
300kHz EXCITATION FREQUENCY,
300kHz, 500mVP-P
INTERFERENCE FREQUENCY
OUTPUT POWER
vs. EXCITATION FREQUENCY SPECTRUM
MAX1441
toc12
EXCITATION FREQUENCY SPECTRUM (kHz)
OUTPUT
POWER
(dBm)
800
600
400
200
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
-100
0
1000
MAX1441
toc13
EXCITATION BANDWIDTH (kHz)
CAPACITANCE
ERROR
(%
FULL
SCALE)
130
110
70
90
30
50
10
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
-0.5
-10
150
CAPACITANCE ERROR
vs. EXCITATION BANDWIDTH
5pF RANGE,
CO_ = 0,
3.6pF INPUT CAPACITANCE
DETECTION DISTANCE
vs. ATxH REGISTER SETTING
MAX1441
toc14
ATxH REGISTER SETTING
DETECTION
DISTANCE
(mm)
30
25
15
20
10
5
0
35
10
20
30
40
50
60
70
80
90
100
0
25cm x 2cm TOUCH PAD
5pF RANGE
20pF RANGE
10pF RANGE
FULL-SCALE CAPACITANCE CHANGE
vs. TEMPERATURE
MAX1441
toc15
TEMPERATURE (°C)
FULL-SCALE
CAPACITANCE
CHANGE
(%FS)
100
75
25
50
0
-25
-1.0
-0.5
0
0.5
1.0
1.5
2.0
2.5
3.0
-1.5
-50
125
5pF RANGE
20pF RANGE
10pF RANGE