MAX11802EWC+T

Overview

The MAX11802EWC+T is a low-power resistive touch-screen controller from the MAX11800–MAX11803 family, manufactured by Analog Devices Inc./Maxim Integrated. It operates on a single supply voltage ranging from 1.70V to 3.6V and features a 12-bit Successive Approximation Register (SAR) ADC with an integrated multiplexer for interfacing with 4-wire resistive touch panels. The device supports SPI serial communication at speeds up to 25MHz. Key technical capabilities include direct and autonomous operating modes, data tagging for measurement type and touch event identification, and digital preprocessing to reduce host processor load. Power consumption is specified at 343µW at 1.7V and 888µW at 3.3V, both measured at 34.4ksps.

Feature Summary

• 12-Bit SAR ADC with Multiplexer: Provides high-resolution X/Y coordinate and touch pressure (Z1/Z2) measurements for 4-wire resistive touch screens.
• Dual Operating Modes: Supports Direct Mode for host-controlled conversions and Autonomous Mode for automatic scanning with on-chip FIFO storage to minimize bus activity.
• Digital Signal Processing: Includes data filtering, aperture mode for spatial filtering, and programmable touch-detect pullup resistors to enhance noise immunity and reduce interrupt frequency.
• Data Tagging: Automatically records measurement types (X, Y, Z1, Z2) and touch events (initial, continuing, release) within the data stream.

Applications

• Mobile Communication Devices
• PDAs, GPS Receivers, and Personal Navigation Devices
• Portable Media Players and Handheld Games
• Point-of-Sale (POS) Terminals

Procurement Notes

Verify the ordering suffix '+T' indicates tape-and-reel packaging when sourcing components. Confirm the 'E' suffix corresponds to the -40°C to +85°C extended temperature range rather than the automotive '-GTC/V+' variant. Ensure the WLP package dimensions (1.6mm x 2.1mm) fit the target PCB footprint constraints.

Selection Notes

Select the MAX11802 specifically when an SPI interface is required; the MAX11803 variant uses I2C. Choose this model over the MAX11800/MAX11801 if autonomous mode operation with FIFO buffering is necessary for system power optimization. Verify that the 12-pin WLP package is compatible with the assembly process compared to the TQFN alternative.

Part Context

This component belongs to the MAX11800–MAX11803 series of ultra-small resistive touch-screen controllers. The MAX11802 is distinguished by its SPI interface capability, whereas the MAX11803 utilizes I2C. Both share identical core functionalities including the 12-bit ADC, autonomous mode, and power management features, differing primarily in communication protocol and specific application interface requirements.

Replacement Considerations

The MAX11800EWC+T serves as a functional substitute if the system design accommodates SPI but requires different configuration defaults or if inventory alignment necessitates swapping between SPI variants within the same package and temperature grade.

FAQ

Does the MAX11802 support autonomous mode?

Yes, the MAX11802 supports autonomous mode, allowing it to periodically scan the touch screen for events without host intervention, using an on-chip FIFO to store results.

What is the maximum SPI clock speed for the MAX11802?

The MAX11802 supports an SPI interface with a maximum clock speed of 25MHz.

How does the device handle touch event identification?

The device includes a data-tagging feature that records the type of measurement performed (X, Y, Z1, or Z2) and the type of touch event (initial touch, continuing touch, or touch release).