MAX1441 Datasheet, PDF (5/41 Pages) Maxim Integrated Products – Automotive, Two-Channel Proximity and Touch Sensor

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