XPT2046 Ver la hoja de datos (PDF) - Unspecified

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componentes Descripción

Fabricante

XPT2046

Touch Screen Controller

Unspecified 

XPT2046 Touch Screen Controller

Theory Of Opration

The XPT2046 is a classic successive approximation register (SAR) analog-to-digital converter (ADC). The

architecture is based on capacitive redistribution, which inherently includes a sample-and-hold function. The

converter is fabricated on a 0.6μm CMOS process. The basic operation of the XPT2046 is shown in Figure 4

The device features an internal 2.5V reference and uses an external clock. Operation is maintained from a single

supply of 2.7V to 5.25V. The internal reference can be overdriven with an external, low-impedance source

between 1V and +VCC. The value of the reference voltage directly sets the input range of the converter.

The analog input (X-, Y-, and Z-Position coordinates, auxiliary input, battery voltage, and chip temperature)

to the converter is provided via a multiplexer. A unique configuration of low on-resistance touch panel driver

switches allows an unselected ADC input channel to provide power and the accompanying pin to provide

ground for an external device, such as a touch screen. By maintaining a differential input to the converter and

a differential reference architecture, it is possible to negate the error from each touch panel driver switch’s

on-resistance (if this is a source of error for theparticular measurement).

Basic Operation of the XPT2046

Figure 4. Basic Operation

Copyright©2007, SHENZHEN XPTEK TECHNOLOGY CO.,LTD http://www.xptek.com.cn

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