QT113 QProx 8-pin Sensor

The QT113 is a variant of the QT110 having variable sensitivity and faster response time in most cases. Unlike

the QT110, it has a variable threshold which can be modified by simply altering the value of the sample

capacitor Cs, which acts to modify gain. In addition, it also includes an 'infinite' max on-duration timeout, so that

it is possible to prevent a recalibration during prolonged detections.

The QT113 is designed for contact sensing applications where faster speed and high sensitivity are paramount,

for example when sensing through thick panels or windows in machine tool applications or certain types of

security monitoring. The QT113 trades off power consumption for speed and sensing range. Also, note that the

device has a consensus filter count of 3 instead of 4, and does not have the drive capability for a piezo 'beeper'.

The QT113 IC is exactly the same in all respects to the QT110 with the following exceptions (refer to Tables

4.2, 4.3, 4.4, and 4.5 in the QT110 datasheet).

Cx Load Capacitance

................................................................. 0 to 100pF

Cs .............................................................................. 10nF to 500nF

Note 1

ms

300

8

Response time

Cs = 10nf to 500nf, Cx = 0

ms

75

0.5

Burst length

Cs = 10nf to 500nf, Cx = 0

ms

80

2.1

Burst spacing interval

Note 1: Lengthens with increasing Cs but decreases with increasing Cx; see Chart 3.

ms/level

100

Negative drift compensation rate

ms/level

1,000

Positive drift compensation rate

samples

3

Consensus filter length

w.r.t. threshold cts.

%

17

Hysteresis

Note 1

counts

12

6

Threshold differential, fixed

Note 1

%

-

Threshold differential, low gain

Note 1

%

-

Threshold differential, medium gain

Note 1

%

-

Threshold differential, high gain

Note 1: All percentage thresholds have been eliminated and replaced with fixed thresholds (high, low gains) w.r.t. the reference level

Typical, see figs 1, 2; Note 1, 2

fF

28

-

1,000

Sensitivity range

S

Note 1

pF

-

Sensitivity - low gain

S[3]

Note 1

pF

-

Sensitivity - medium gain

S[2]

Note 1

pF

-

Sensitivity - high gain

S[1]

Cs = 10nF to 100nF

A

700

Supply current

Note 1: All percentage thresholds have been eliminated and replaced with a fixed threshold w.r.t. reference level

Note 2: Sensitivity depends on value of Cx and Cs. Refer to Charts 1, 2.