Quantum Research Group Ltd.
4 August 2004
QT111-I / QT111H-I QProx™ 8-pin Sensor
See QT110 datasheet for primary information. This sheet only lists differences with the QT110.
This part is only available in -I suffix (-40..+85C)
Description
The QT111 is a touch sensor IC having recalibration timeouts (“max on-duration”) of 5 minutes and infinity. This
allows the device to be used in situations where recalibration timeouts are not desired, for example in certain
consumer, machine tool and process control applications where continuous touch over long periods is desired,
like hand-on-joystick sensors, dead-man switches, etc. Although the primary application of the device is still as a
‘touch sensor’, longer timeouts also aknowledge alternate uses for the QT110 family, for example in process
controls.
Differences with QT110
The QT111 sensor is exactly the same in all respects to the QT110 with the following exceptions shown in bold
(refer to Table 2-1 in the QT110 datasheet):
Table 2-1 Output Mode Strap Options
Tie
Pin 3 to:
DC Out
DC Out
Toggle
Pulse
Vdd
Vdd
Gnd
Gnd
Tie
Pin 4 to:
Vdd
Gnd
Gnd
Vdd
Max On-
Duration
300s
infinite
300s
300s
All other operating modes, specifications, and wiring should be read from the QT110 data sheet.
QT111H Version
The QT111H version is the same as the QT111 except has an active-high output.
Cautionary Notes
Care should be taken in infinite timeout mode that the Cs and Cx capacitances and the Vcc supply do
not drift substantially over the course of a detection; if any of these parameters change sufficiently
during the course of an active detection (remember: drift compensation is never performed during a
detection event) the sensor can either ‘stick on’ after the detected object is removed, or, the QT110’s
apparent sensitivity will be substantially reduced for a period of time until drift compensation can
recover the proper reference level. If possible, uses the lowest gain setting when using with long
timeouts.
If the sensor ‘sticks on’ after the detected object or substance is removed from the sense element, the
only way to clear the sensor may be to remove power momentarily in order to induce a full
recalibration.
Package Marking - QT111-I
DIP Package:
DIP devices are marked 'QT111'
SO8 Package:
Marked 'QT1 Y'
Package Marking - QT111H-I
DIP Package:
Not offered
SO8 Package:
Marked 'QT1 C'
QT111 QProx™ 8-pin Sensor
© 1999 QRG Ltd.
QUANTUM [ QUANTUM RESEARCH GROUP ]
