at42qt113b ATMEL Corporation, at42qt113b Datasheet - Page 10

• Manufacturer Part Number: at42qt113b
• Manufacturer: ATMEL Corporation

3.1.7
3.2
3.2.1
3.2.2
10
Output Features
AT42QT113B
Response Time
Introduction
DC Mode Output
Figure 3-2.
Option strap configurations are read by the QT113B only on power-up. Configurations can only
be changed by powering the QT113B down and back up again; again, a microcontroller can
directly alter most of the configurations and cycle power to put them in effect.
The QT113B‘s response time is highly dependent on burst length, which in turn is dependent on
Cs and Cx (see
slows, while increasing levels of Cs reduce response time.
typical effects of Cs and Cx on response time.
The QT113B is designed for maximum flexibility and can accommodate most popular sensing
requirements. These are selectable using strap options on pins OPT1 and OPT2. All options are
shown in
Table 3-2.
The output of the QT113B can respond in a DC mode, where the output is active-low upon
detection. The output will remain active-low for the duration of the detection, or until the Max
On-Duration expires (if not infinite), whichever occurs first. If a max on-duration timeout occurs
first, the sensor performs a full recalibration and the output becomes inactive until the next
detection.
In this mode, three Max On-Duration timeouts are available: 10 seconds, 60 seconds, and
infinite.
DC Out
DC Out
Toggle
DC Out
Table
microcontroller
Powering From a CMOS Port Pin
Output Mode Strap Options
CMOS
3-2.
Figure A-1
PORT X.m
PORT X.n
and
Tie Pin 3 To...
Figure A-2 on page
Gnd
Gnd
Vdd
Vdd
OUT
QT113B
Vdd
Vss
Tie Pin 4 To...
20). With increasing Cs, response time
0.01µF
Gnd
Gnd
Vdd
Vdd
Figure A-3 on page 20
Max On-duration
Infinite
9525B–AT42–09/10
10s
60s
10s
shows the