at42qt100a ATMEL Corporation, at42qt100a Datasheet - Page 3

• Manufacturer Part Number: at42qt100a
• Description: Qtouch? Charge Transfer Ic
• Manufacturer: ATMEL Corporation

1.3
2. Overview of the QT100A
2.1
9531A–AT42–02/09
Schematic
Introduction
Figure 1-1.
The QT100A charge-transfer (QT
detecting near-proximity or touch. It will project a touch or proximity field through any dielectric
like glass, plastic, stone, ceramic, and even most kinds of wood. It can also turn small metal-
bearing objects into intrinsic sensors, making them responsive to proximity or touch. This
capability, coupled with its ability to self-calibrate, can lead to entirely new product concepts.
The QT100A is designed specifically for human interfaces, like control panels, appliances, toys,
lighting controls, or anywhere a mechanical switch or button may be found. It includes all
hardware and signal processing functions necessary to provide stable sensing under a wide
variety of changing conditions. Only a single low cost, noncritical capacitor is required for
operation.
The QT100A can also project a proximity field to several centimeters with the proper electrode
and circuit design.
Two package types are offered, one of which can directly replace the QT100’s SOT-23-6
package but with a reduced thickness.
These devices are intended to replace the QT100.
Refer to the following application note for more information on migrating from QT100:
• QTAN0028 – Sensitivity Differences When Migrating from QT100 to QT100A
2 ~ 5V
Basic Circuit Configuration for 6-pin WSON Package
*Cb
*Note: Bypass capacitor Cb should be tightly wired
between Vdd and Vss
OUT
VDD
VSS
™
) touch sensor is a self-contained digital IC capable of
QT100A, 6-WSON Pkg.
SNSK
SYNC
SNS
3
4
Cs
Rs
ELECTRODE
AT42QT100A
SENSE
Cx
3