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LC717A10AR Datasheet, PDF (10/11 Pages) Sanyo Semicon Device – Capacitance-Digital-Converter LSI for Electrostatic Capacitive Touch Sensors
Continued from the previous page.
Pin Name
I/O
LC717A10AR
Pin Functions
VDD
SA0/SO
I/O
Slave address selection (I2C)
/ Data output (SPI)
Pin Type
R
VSS
Buffer
VDD
Power supply (2.6V to 5.5V) *1
VSS
Ground (Earth) *1 *2
*1) Inserting a high-valued capacitor and a low-valued capacitor in parallel between VDD and VSS is recommended.
In this case, the small-valued capacitor should be at least 0.1μF, and is mounted near the LSI.
*2) When VSS terminal is not grounded in battery-powered mobile equipment, detection sensitivity may be degraded.
Details of Pin Functions
●Cin0 to Cin15
These are the capacitance-sensor-input pins. These pins are used by connecting them to the touch switch pattern.
Cin and the Cdrv wire patterns should be close to each other. By doing so, Cdrv and Cin patterns are capacitively
coupled. Therefore, LSI can detect capacitance change near each pattern as 8bit digital data.
However, if the shape of each pattern or the capacitively coupled value of Cdrv is not appropriate, it may not be able
to detect the capacitance change correctly.
In this LSI, there is a two-stage amplifier that detects the changes in the capacitance and outputs analog-amplitude
values. Cin0 to Cin15 are connected to the inverting input of the 1st amplifier.
During measurement process, channels other than the one being measured are all in “Low” condition.
Leave the unused terminals open.
●Cref, CrefAdd
These are the reference-capacitance-input pins. These are used by connecting to the wire pattern like Cin pins or are
used by connecting any capacitance between this pin and Cdrv pin.
In this LSI, there is a two-stage amplifier that detects the changes in the capacitance and outputs analog-amplitude
values. Cref is connected to the non-inverting input of the 1st amplifier.
Due to the parasitic capacitance generated in the wire connections of Cin pins and their patterns, as well as the one
generated between the wire patterns of Cin and Cdrv pins, Cref may not detect capacitance change of each Cin pin
accurately. In this case, connect an appropriate capacitance between Cref and Cdrv to detect capacitance change
accurately.
However, if the difference between the parasitic capacitance of each Cin pin is extremely large, it may not detect
capacitance change of each Cin pin correctly.
CrefAdd can be used as additional terminal for Cref. Leave the CrefAdd open if not in used.
●Cdrv
It is the output pin for capacitance sensors drive. It outputs the pulse voltage which is needed to detect capacitance at
Cin0 to Cin15.
Cdrv and Cin wire patterns should be close to each other so that they are capacitively coupled.
●INTOUT
It is the interrupt-output pin.
It is used by connecting to a main microcomputer if necessary, and use as interrupt signal. (High Active)
Leave the terminal open if not in used.
●SCL/SCK
Clock input (I2C) / Clock input (SPI)
It is the clock input pin of the I2C compatible bus or the SPI depending on the mode of operation.
No.A2161-10/11