AR1020T-I/SS Microchip Technology, AR1020T-I/SS Datasheet - Page 30

• Manufacturer Part Number: AR1020T-I/SS
• Description: IC TOUCH SCREEN CTRLR 20-SSOP
• Manufacturer: Microchip Technology
• Type: Resistiver

Specifications of AR1020T-I/SS

• Package / Case: 20-SSOP
• Touch Panel Interface: 4-Wire, 5-Wire, 8-Wire
• Number Of Inputs/keys: 3 Key
• Resolution (bits): 10 b
• Data Interface: I²C, Serial, SPI™
• Voltage - Supply: 3.3 V ~ 5.5 V
• Current - Supply: 17mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Voltage Supply Source: Single Supply
• Supply Voltage Range: 3.135V To 3.465V, 4.75V To 5.25V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: TSSOP
• No. Of Pins: 20
• Svhc: No SVHC (15-Dec-2010)
• Supply: RoHS Compliant
• Ic Function: Touch Screen Controller
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Sampling Rate (per Second): -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.3 4-Wire Sensor
A 4-wire resistive touch sensor consists of a Stable and Flex layer, electrically separated by spacer dots. The
layers are assembled perpendicular to each other. The touch position is determined by first applying a voltage
gradient across the flex layer and using the stable layer to measure the flex layer’s touch position voltage. The
second step is applying a voltage gradient across the stable layer and using the flex layer to measure the stable
layer’s touch position voltage.
The measured voltage at any position across a driven axis is predictable. A touch moving in the direction of the
driven axis will yield a linearly changing voltage. A touch moving perpendicular to the driven axis will yield a
relatively unchanging voltage.
Figure 14: 4-Wire Decoding
DS41393A-Page 26
© 2009 Microchip Technology, Inc.