ZSSC3122 Datasheet, PDF (57/64 Pages) List of Unclassifed Manufacturers – Low Voltage Capacitive Sensor Signal Conditioner

ZSSC3122 Datasheet
7.4 Differential Input Capacitance
This example shows that the full functionality of the ZSSC3122 including the applications illustrated in examples 1,
2, and 3, can be implemented with a differential input capacitance. The capacitor C_CC allows a non-galvanic con-
nection (e.g., to the moving part of a motion sensor as part of the sensor construction), but it is not needed for
sensor types with existing galvanic connections.
The configuration settings are shown in Table 7.4.
The differential bit is set to select differential input
capacitance. In this example, SPI has been selected
in Update Mode at the fastest update rate. The SPI
phase is set to 1 so that the master samples MISO
on the negative edge of SCLK. The EEPROM has
been locked.
The AFE configuration registers select 14-bit reso-
lution for capacitance and 10-bit resolution for internal
temperature. Because this is the differential config-
uration, both the internal reference and offset capaci-
tors are set to zero.
V_{SUPPLY (+1.8V to 5.5V)}
0.1µF 0.1µF
GND
VDD
Vcore
VSS
C0
CC
C1
cLite^™
ZSSC3122
Ready
SDA/MISO
SCL/SCLK
SS
Alarm_High
Alarm_Low
Figure 7.4 Differential Input Capacitance Example
Table 7.4 Example 4: Configuration Settings
Configuration Register 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
ZMDI_Config (Table 5.2) 0^† 0
0
1
1
0 00 0 1 1XX0 0 0
Cust_Config (Table 5.5) 0^† 0^† 0
0
1
0 0000101000
C_Config (Table 5.3)
0^†
1
0
0
1
1 0^† 0^† 0^† 0^† 0 0 0 0 0 0
T_Config (Table 5.4)
1^†
0^†
0^†
0^†
0
1 0^† 1* 1* 0* 0* 1* 0* 0* 1* 0*
* The factory settings are set for a full span temperature range from -20°C to +125°C. Do not change this setting unless a different temperature range is needed.
† Reserved setting – do not change factory settings.
© 2016 Integrated Device Technology, Inc.
57
January 25, 2016