Microchip ATMXT2912TD Based in-car Ultra-wide Touch Screen Solution

To better meet the need for a safe, intuitive and easy-to-use in-vehicle user interface with richer entertainment systems, Microchip has introduced the maxTouch MXT2912TD-UW touchscreen controller to simplify system development for electric vehicles (EVs), advanced driver assistance systems (ADAS) and premium vehicles with commonly used ultra-wide screens.

The MXT2912TD-UW is the first touch-screen controller to be certified as an in-vehicle A-plus controller. This is the first single-chip solution for touchscreen controllers that is AEC-Q100 certified for automotive applications, supporting displays up to 45" and extremely wide aspect ratios, as well as liquid crystal display (LCD) and light-emitting diode (OLED) display technologies.

The MXT2912TD reduces the requirement for multiple touch controllers within automotive human-machine interface (HMI) displays and is not affected by display resolution, contributing to the same user experience as smartphones.

The MaxTouch series inherently has excellent signal to dry ratio (SNR) characteristics, even in wet conditions, through a variety of cover materials and thickness customers support multi-finger thick gloves and waterproof Touch. The total number of channels is 162, and the pich size is generally set at about 6mm. Can support cover thickness of 10mm Glass or 5mm PMMA, mainly to do On-lens support DITO/SITO process. And the mutual tolerance of one.

Principle introduction:

Self-capacitance is mainly to measure the capacitance of the signal line itself, the advantages of simple, small calculation. The disadvantages are: virtual two points and slow speed. So mutual capacitance is introduced: measuring the capacitance between two signals that intersect vertically. The advantages are: real multi-point and fast. The disadvantages are: complex calculation, high power consumption and high cost. Since mutual capacitance in one, they do compensation with each other.

Development design note: Microchip has a complete set of development tools that can be given to customers to save their development cycle.

1.FPC design main matters:

Generally refers to the flexible circuit board, is made of polyimide or polyester film as a substrate with a high degree of reliability, excellent flexible printed circuit boards, with high wiring density, light weight, thin thickness characteristics!

A. copper foil substrate: basically divided into two kinds of electrolytic copper and calendered copper. The thickness of the common 1oz 1/2oz and 1/3 oz!

B. substrate film: the common thickness of 1 mil and 1/2 mil two

C. Protective film: for surface insulation. Common thicknesses are 1 mil and 1/2 mil.

Note: The same type of calendered copper is stronger than electrolytic copper in bending. Production process: surface treatment: sink gold, this gold is not pure gold, but nickel gold, after sinking gold products in the anti-oxidation performance has significantly improved!

2. In the FPC mechanism design mainly involves the following aspects:

A. FPC bending to try to avoid the use of 90 ° way, in order to improve the installation yield. Figure 1 below

B. The back of the components area steel patch will do ground connection, in the whole body is recommended to increase the steel patch and the motherboard ground connection design.

C. In the FPC shielding contact line position need to consider the institution to avoid empty 0.2mm height. The following Figure II, for the ITO structure should pay particular attention.

                         Figure 1

                         Figure 2

►Scene application diagram

►Display board photo

►Scenario cube diagram

►PCB drawing

►Core technical advantages

1. Single chip supports maximum 41" touch screen controller. 2: Support thick gloves with multiple fingers 3: Support waterproof

►Program specifications

1. Package LQFP 24*24*1.4mm 2: AEC-Q100 vehicle specification certification. 3: Support VDD 3.3V power supply.