The MAX11800–MAX11803 low-power touch-screen controllers operate from a single supply of 1.70V to 3.6V, targeting power-sensitive applications such as handheld equipment. The devices contain a 12-bit SAR ADC and a multiplexer to interface with a resistive touch-screen panel. A digital serial interface provides communications.
The MAX11800–MAX11803 include digital preprocessing of the touch-screen measurements, reducing bus loading and application-processor resource requirements. The included smart interrupt function generator greatly reduces the frequency of interrupt servicing to the devices. The MAX11800–MAX11803 enter low-power modes automatically between conversions to save power, making the devices ideal for portable applications.
The MAX11800/MAX11801 offer two modes of operation: direct and autonomous. Direct mode allows the application processor to control all touch-screen controller activity. Autonomous mode allows the MAX11800/MAX11801 to control touch-screen activity, thereby freeing the application processor to perform other functions. In autonomous mode, the devices periodically scan the touch screen for touch events without requiring host-processor intervention. This can be used to reduce system power consumption. An on-chip FIFO is used during autonomous mode to store results and increase effective data throughput and lower system power.
The MAX11800–MAX11803 support data-tagging, which records the type of measurement performed; X, Y, Z1, or Z2, and the type of touch event; initial touch, continuing touch, or touch release.
The MAX11800/MAX11802 support the SPI™ serial bus. The MAX11801/MAX11803 support the I²C serial bus. The MAX11800–MAX11803 are available in 12-pin TQFN and 12-pin WLP packages, and are specified over the -40°C to +85°C (extended) and -40°C to +105°C (automotive) temperature ranges.
Key Features
Applications/Uses
34-Wire Touch-Screen Interface
X/Y Coordinate and Touch Pressure Measurement
Ratiometric Measurement
12-Bit SAR ADC
Single 1.7V to 3.6V Supply
Two Operating Modes—Direct and Autonomous
Data Tagging Provides Measurement and Touch Event Information
Data Filtering Provides Noise Reduction
Aperture Mode† Provides Spatial Filtering
Digital Processing Reduces Bus Activity and Interrupt Generation
Programmable Touch-Detect Pullup Resistors
Auto Power-Down Control for Low-Power Operation
25MHz SPI Interface (MAX11800/MAX11802)
400kHz I²C Interface (MAX11801/MAX11803)
1.6mm x 2.1mm, 12-Pin WLP and 4mm x 4mm, 12-Pin TQFN
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