QT118H 查看數據表（PDF） - Quantum Research Group

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QT118H

CHARGE-TRANSFER TOUCH SENSOR

Quantum Research Group 

lQ

QProx™ QT118H

CHARGE-TRANSFER TOUCH SENSOR

Less expensive than many mechanical switches

Projects a ‘touch button’ through any dielectric

Turns small objects into intrinsic touch sensors

100% autocal for life - no adjustments required

Only one external part required - a 1¢ capacitor

Piezo sounder direct drive for ‘tactile’ click feedback

LED drive for visual feedback

3V 20µA single supply operation

Toggle mode for on/off control (strap option)

10s or 60s auto-recalibration timeout (strap option)

Pulse output mode (strap option)

Gain settings in 3 discrete levels

Simple 2-wire operation possible

HeartBeat™ health indicator on output

Vdd

1

Out

2

O pt1

3

O pt2

4

8

Vss

7

Sns2

6

Sns1

5

Gain

APPLICATIONS -

Light switches

Industrial panels

Appliance control

Security systems

Access systems

Pointing devices

Elevator buttons

Toys & games

The QT118H charge-transfer (“QT’”) touch sensor is a self-contained digital IC capable of detecting near-proximity or touch. It will

project a sense field through almost any dielectric, like glass, plastic, stone, ceramic, and most kinds of wood. It can also turn

small metal-bearing objects into intrinsic sensors, making them respond to proximity or touch. This capability coupled with its

ability to self calibrate continuously can lead to entirely new product concepts.

It is designed specifically for human interfaces, like control panels, appliances, toys, lighting controls, or anywhere a mechanical

switch or button may be found; it may also be used for some material sensing and control applications provided that the presence

duration of objects does not exceed the recalibration timeout interval.

The IC requires only a common inexpensive capacitor in order to function. A bare piezo beeper can be connected to create a

‘tactile’ feedback clicking sound; the beeper itself then doubles as the required external capacitor, and it can also become the

sensing electrode. An LED can also be added to provide visual sensing indication. With a second inexpensive capacitor the device

can operated in 2-wire mode, where both power and signal traverse the same wire pair to a host. This mode allows the sensor to

be wired to a controller with only a twisted pair over a long distances.

Power consumption is under 20µA in most applications, allowing operation from Lithium cells for many years. In most cases the

power supply need only be minimally regulated.

The IC’s RISC core employs signal processing techniques pioneered by Quantum; these are specifically designed to make the

device survive real-world challenges, such as ‘stuck sensor’ conditions and signal drift. Even sensitivity is digitally determined and

remains constant in the face of large variations in sample capacitor Cs and electrode Cx. No external switches, opamps, or other

analog components aside from Cs are usually required.

The device includes several user-selectable built in features. One, toggle mode, permits on/off touch control, for example for light

switch replacement. Another makes the sensor output a pulse instead of a DC level, which allows the device to 'talk' over the

power rail, permitting a simple 2-wire interface. The Quantum-pioneered HeartBeat™ signal is also included, allowing a host

controller to monitor the health of the QT118H continuously if desired. By using the charge transfer principle, the IC delivers a

level of performance clearly superior to older technologies in a highly cost-effective package.

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AVAILABLE OPTIONS

TA

00C to +700C

-400C to +850C

SOIC

QT118H-S

QT118H-IS

8-PIN DIP

QT118H-D

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©1999-2000 Quantum Research Group

R1.03 / 0302

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