AD7143ACPZ Analog Devices Inc, AD7143ACPZ Datasheet - Page 23
![IC, CDC, 16BIT, SMD, LFCSP-16, 7143](/photos/18/98/189849/ge16lfcsp05-40_sml.jpg)
AD7143ACPZ
Manufacturer Part Number
AD7143ACPZ
Description
IC, CDC, 16BIT, SMD, LFCSP-16, 7143
Manufacturer
Analog Devices Inc
Datasheet
1.AD7143ACPZ.pdf
(56 pages)
Specifications of AD7143ACPZ
Supply Voltage Range
2.6V To 3.6V
Operating Temperature Range
-40°C To +85°C
Digital Ic Case Style
LFCSP
No. Of Pins
16
Svhc
No SVHC (18-Jun-2010)
Package / Case
LFCSP
Base Number
7143
Ic Function
Programmable Controller For Capacitance Touch Sensors
Rohs Compliant
Yes
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD7143ACPZ-1
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Company:
Part Number:
AD7143ACPZ-1500RL7
Manufacturer:
NSC
Quantity:
654
Part Number:
AD7143ACPZ-1500RL7
Manufacturer:
ADI/亚德诺
Quantity:
20 000
CAPACITANCE SENSOR BEHAVIOR WITH
CALIBRATION
The AD7143 on-chip adaptive calibration algorithm prevents
sensor detection errors, such as the one shown in Figure 34.
This is achieved by monitoring the CDC ambient levels and
readjusting the initial STAGE_OFFSET_HIGH and
STAGE_OFFSET_LOW values according to the amount of
ambient drift measured on each sensor.
The internal STAGE_HIGH_THRESHOLD and
STAGE_LOW_THRESHOLD values, shown in Equation 1 and
Equation 2, are automatically updated based on the new
STAGE_OFFSET_HIGH and STAGE_OFFSET_LOW values.
This closed-loop routine ensures the reliability and repeatable
operation of every sensor connected to the AD7143 under
dynamic environmental conditions. Figure 35 shows a
simplified example of how the AD7143 applies the adaptive
calibration process resulting in no interrupt errors under
changing CDC ambient levels due to environmental conditions.
On-Chip Logic Stage High Threshold Calculation
On-Chip Logic Stage Low Threshold Calculation
⎛
⎜
⎜
⎜
⎜
⎝
⎛
⎜
⎜
⎜
⎜
⎝
STAGE
STAGE
⎛
⎜
⎝
⎛
⎜
⎝
STAGE
STAGE
_
_
HIGH
LOW
_
_
OFFSET
OFFSET
_
_
THRESHOLD
THRESHOLD
_
_
HIGH
LOW
16
−
16
−
=
=
STAGE
STAGE
STAGE
STAGE
_
_
_
OFFSET
OFFSET
_
SF
SF
4
Rev. 0 | Page 23 of 56
4
_
_
AMBIENT
AMBIENT
_
_
LOW
HIGH
⎞
⎟
⎠
+
⎞
⎟
⎠
+
⎞
⎟
⎟
⎟
⎟
⎠
⎛
⎜
⎝
⎞
⎟
⎟
⎟
⎟
⎠
⎛
⎜
⎝
×
STAGE
×
STAGE
NEG
Figure 35. Typical Sensor Behavior with Calibration Applied on the Data Path
POS
1
2
3
4
5
6
INITIAL STAGE_OFFSET_HIGH REGISTER VALUE.
POST CALIBRATED REGISTER STAGE_HIGH_THRESHOLD.
POST CALIBRATED REGISTER STAGE_HIGH_THRESHOLD.
INITIAL STAGE_LOW_THRESHOLD.
POST CALIBRATED REGISTER STAGE_LOW_THRESHOLD.
POST CALIBRATED REGISTER STAGE_LOW_THRESHOLD.
_
_
THRESHOLD
CHANGING ENVIRONMENTAL CONDITIONS
_
_
THRESHOLD
1
4
OFFSET
OFFSET
4
4
_
_
LOW
SENSOR 2 INT
HIGH
_
ASSERTED
_
SENSITIVIT
SENSITIVIT
⎞
⎟
⎠
⎞
⎟
⎠
+
SENSOR 1 INT
2
5
+
ASSERTED
Y
Y
(1)
(2)
3
6
t
STAGE_HIGH_THRESHOLD
(POST CALIBRATED
REGISTER VALUE)
CDC AMBIENT
VALUE DRIFTING
STAGE_LOW_THRESHOLD
(POST CALIBRATED
REGISTER VALUE)
AD7143