SX8650 Datasheet, PDF (18/56 Pages) Semtech Corporation – World’s Lowest Power & Smallest Footprint 4-wire Resistive Touchscreen Controller with 15kV ESD

SX8650
World’s Lowest Power & Smallest Footprint 4-wire
Resistive Touchscreen Controller with 15kV ESD
ADVANCED COMMUNICATIONS & SENSING
DATASHEET
3.2. Channel Pins
3.2.1. X+, X-, Y+. Y-
The SX8650's channel pins (X+, X-, Y+, Y-) directly connect to standard touch screen X and Y resistive layers. The
SX8650 separately biases each of these layers and converts the resistive values into (X,Y) coordinates.
The channel pins are protected to VDD and GROUND.
Figure 9 shows the simplified diagram of the X+, X-, Y+, Y- pins.
VDD
X+
X-
Y+
Y-
R_chn
Touch Screen
Interface
Figure 9. Simplified diagram of X+, X-, Y+, Y- pins
3.2.2. AUX
The SX8650 interface includes an AUX pin that serves two functions: an ADC input; and a start of conversion trigger. When
used as an ADC, the single ended input range is from GND to VDD, referred to GND. When the AUX input is configured to
start conversions, the AUX input can be further configured as a rising and / or falling edge trigger.
The AUX is protected to VDD and GROUND.
Figure 10 shows a simplified diagram of the AUX pin.
VDD
ADC
AUX
Control
Figure 10. Simplified diagram of AUX
ACS Revision V2.15/October 2009
©2009 Semtech Corp.
Page 17
www.semtech.com