AT42QT2161-MMU Atmel, AT42QT2161-MMU Datasheet - Page 12

• Manufacturer Part Number: AT42QT2161-MMU
• Description: IC TOUCH SENSOR 16KEY QFN M-MOD
• Manufacturer: Atmel
• Type: Capacitiver

Specifications of AT42QT2161-MMU

• Touch Panel Interface: 8, 2-Wire
• Number Of Inputs/keys: 16 Key, Slider
• Resolution (bits): 10 b
• Data Interface: I²C, Serial
• Voltage Reference: Internal
• Voltage - Supply: 1.8 V ~ 5.5 V
• Current - Supply: 1.14mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3.9
3.9.1
12
Setting the Slider
AT42QT2161
Introduction
For better surface moisture suppression, the outer perimeter of X should be as wide as possible,
and there should be no ground planes near the keys. The variable “T” in this drawing represents
the total thickness of all materials that the keys must penetrate.
Figure 3-6.
Note:
Groups of keys can be configured as a slider, in addition to their use as keys. The slider uses the
Y0 line of the matrix and must start at X0, with the keys placed in consecutive numerical order.
The slider can take up a programmable number of keys on the Y0 line. The remaining keys on
that Y line behave as normal.
Positional data is calculated in a customizable range of 2 bits (0 – 3) to 8 bits (0 – 255).
Geometric constraints may mean that the data will not reach the full range. Thinner dielectric or
the use of more keys in a slider will increase the data range towards the ends.
Stability of the reported position will be dependent on the amount of signal on the slider keys.
Running at higher resolutions, with a thick panel might produce a fluctuating reported position.
“T” should ideally be similar to the complete thickness the fields need to penetrate to the touch
surface. Smaller dimensions will also work but will give less signal strength. If in doubt, make the
pattern coarser. The lower figure shows a simpler structure used for compact key layouts, for
example for mobile phones. A layout with a common X drive and two receive electrodes is
depicted
Recommended Key Structure
X0
Y0
Y1
9614A–AT42–08/10