The AT42QT101x single key capacitive touch controller family provide touch key replacements for mechanical buttons. The ICs are low cost, and as such can be added to designs with minimal impact on the bill of materials.
Each Device has Different Operation: n AT42QT1010 (QT1010)
Single key with timer to reset “stuck key” condition. n AT42QT1011 (QT1011) Single key with no reset timer. n AT42QT1012 (QT1012) Single key with touch-on/touch off or “toggle” operation and power down timer
The Devices have the following Features in Common n 2.9 mm x 1.6 mm SOT-23 package n Low power consumption (17 µA at 1.8V) n Low cost n Easy to implement n Range of response speed settings n Can be configured for use as a proximity sensor
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AT42QT1010 and AT42QT1011
The AT42QT1010 and AT42QT1011 are identical apart from their behavior when the sensor is “in detect” for an extended period. The AT42QT1010 has a “maximum on” duration of ~ 60s. If there is an obstruction on the sensor, the device output will go low after the “maximum on” detection period, so that subsequent touches can be detected. The AT42QT1011 has no timer and the device will remain on whilst the sensor is activate.
Speed Settings
The AT42QT1010 and AT42QT1011 have three speed settings: n For n n
devices where a quick response is required, a fast response setting is available with a 12.2 ms maximum response time.
It is also possible to set up the device for low power consumption, at the expense of a slower response time of up to 88.6 ms. A third option is to synchronize the device to an external clock which makes it possible to synchronize several ICs in the same device. This technique can be used to enhance noise immunity by syncing to a noise source such as mains. The response time is then dependent on the external clock.
When the device is in low power mode or when the synchronisation mode is selected, a HeartBeat™ output is available. This