CAP1293 Datasheet, PDF (14/63 Pages) Microchip Technology – 3-Channel Capacitive Touch Sensor with Proximity

CAP1293
4.0 GENERAL DESCRIPTION
The CAP1293 is a multiple channel capacitive touch sensor. It contains three (3) individual capacitive touch sensor
inputs with programmable sensitivity for use in touch sensor applications. Each sensor input is calibrated to compensate
for system parasitic capacitance and automatically recalibrated to compensate for gradual environmental changes.
In addition, the CAP1293 can be configured to detect proximity on one or more channels with an optional signal guard
to reduce noise sensitivity.
The CAP1293includes Multiple Pattern Touch recognition that allows the user to select a specific set of buttons to be
touched simultaneously. If this pattern is detected, a status bit is set and an interrupt is generated.
The CAP1293 has Active and Standby states, each with its own sensor input configuration controls. The Combo state
allows a combination of sensor input controls to be used which enables one or more sensor inputs to operate as buttons
while another sensor input is operating as a proximity detector. Power consumption in the Standby and Combo states
is dependent on the number of sensor inputs enabled as well as averaging, sampling time, and cycle time. Deep Sleep
is the lowest power state available, drawing 5µA (typical) of current. In this state, no sensor inputs are active, and com-
munications will wake the device.
The device communicates with a host controller using SMBus / I²C. The host controller may poll the device for updated
information at any time or it may configure the device to flag an interrupt whenever a touch is detected on any sensor
pad.
A typical system diagram is shown in FIGURE 4-1:.
FIGURE 4-1:
SYSTEM DIAGRAM FOR CAP1293
3.0V to 5.5V
10kOhm
resistors
Embedded
Controller
3.0V to 5.5V
Touch
Button
Proximity
Sensor
0.1uF
VDD
CS1
CAP1293
GND
CS3
SG*
* CS2 / SG is a multi-function pin. If not
using the signal guard shown here, CS2
can be another touch button.
1.0uF
4.1 Power States
The CAP1293 has 4 power states depending on the status of the STBY, COMBO, and DSLEEP bits. When the device
transitions between power states, previously detected touches (for channels that are being de-activated) are cleared
and the sensor input status bits are reset.
1. Active - The normal mode of operation. The device is monitoring capacitive sensor inputs enabled in the Active
state.
DS00001566B-page 14
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