ROHM Develops a Capacitive Sensing Multi-Touch Controller IC,"BU21018MWV"


ROHM Co., Ltd. (Kyoto-based) has developed a low-current-consumption, capacitive sensing multi-touch controller IC, "BU21018MWV," for multi-touch panels that have a growing market as input interfaces used in mobile and netbook PCs. This "BD21018MWV" has acquired the "Windows Touch AQ (Additional Qualification)" as a 10.1-inch size IC for Windows7 compatible touch panels that have become the mainstay of netbook PCs of Microsoft in U.S., and will be soon supplied to touch sensor module manufacturers. ROHM has already launched mass-production of this product on a monthly production scale of 50,000 units in September 2010 (at a sample price of 1,000 yen per unit). As for production, ROHM uses its head office (Kyoto based) for the front-end process and ROHM Integrated Systems (Thailand) Co., Ltd. (Thailand-based) for the rear-end process.

The multi-touch function that enables intuitive operations such as enlargement/reduction of photos and sliding of screens by touching the LCD with fingers has come to be commonly mounted to recent smartphones. With the adoption of the multi-touch function for the Microsoft OS "Windows7" as the "Windows Touch" function, its use is further expected for more and more applications in the future. Until now, in order to mount a touch panel controller IC used in such a touch panel, a ground shield had to be provided for the sensor panel to shut off noise in the liquid crystals. This newly developed "BU21018MWV" achieves substantial enhancement of noise resistance performance by incorporating a dedicated noise filter in the hardware in addition to micro controller software control, eliminating the need to provide a ground shield for the panel. This also makes it possible to cut the cost of the sensor panel by 20% or more. As for noise protection, conventional touch panel controller systems needed to increase the number of clocks of the micro controller and thereby provide current consumption of about 5 mA (including that of the micro controller). In contrast, since the "BU21018MWV" has a built-in noise filter in the hardware, it can minimize the load applied to the micro controller, eventually making it possible to reduce current consumption by about 30% compared to that of conventional products.
The acquisition of the "Windows Touch AQ" represents Microsoft's objective certification of compatibility with "Windows7". This gives notebook PC and other PC manufacturers a sense of security in using the "BU21018MWV."

This "BU21018MWV" incorporates an 8-bit micro controller in the CPU. In addition, ROHM is developing , under license agreement, products that have a built-in ARM-based CPU and offer further advanced processing such as acquisition of three or more coordinate points. And, ROHM is jointly developing touch sensor modules for different panel sizes. Besides the capacitive sensing controller ICs, ROHM also offers a wide range of resistive sensing multi-touch controller ICs that enable multi-touch operation via direct use of existing 4-wire resistive sensing touch panels. Going forward, ROHM will work to expand the lineup of various types of touch panel controller ICs.

Photos of Product

Gesture Function (e.g. rotating, flicking, pinching, etc.) BU21018MWV Evaluation Board / BU21018MWV Controller IC

Major Specification

Package Sensor(SIN) Reference(SREF) Host I/F Power Supply
36 pin 2 pin (Used
separately on X and Y sides)
I2C/SPI Analog: 2.7-3.6V(Built-in LDO)
Digital: 1.7-2.0V(Possible to supply
power using LDO)
Noise Filter Programmable Sensing Speed Sensitivity
  • ΔFilter
  • ΔFIR Filter
Built-in CPU
Variable algorithm
per 36 channels
32×4 steps


  • Multi-touch
    An input method with the ability to intuitively input operations such as the movement, rotation, enlargement, and reduction of an object by touching a number of positions of the object at one time. This is one of the functions included in input devices that provide instructions for position and movement by touching the panel with fingers or dedicated pins.
  • Capacitive sensing
    A technology for detecting position by measuring variations in electrode capacitance made by touching a touch panel with fingers. This technology is suited for multi-touch systems compared to the resistive sensing technology that senses variations in pressure.
Products Capacitive Sensor Control IC Series