Cypress’s Gen4 TrueTouch touchscreen controllers were worth the wait

9/27/2011 11:43 PM EDT

Cypress's Dhwani Vyas put it best, "Finally [we] have the part I have been waiting for!" He was referring to the company's new Gen4 family of touchscreen controllers that are the first to feature an ARM 32-bit core, along with proprietary LCD noise cancellation technology called DisplayArmor that eliminates the need for an extra shield layer of glass and its associated air gap, thereby reducing display thickness by up to 1 mm and lowering overall cost and weight.

Other key features of the new Gen4 TrueTouch include a fast refresh rate of 400 Hz, a 1-kHz scan frequency, and accuracy of 0.2 mm (useful for Asian characters), a low active power consumption of 2 mW and a deep sleep mode that pulls only 1.8 microwatts. Wake-up is provided via an address match on the COM port.

To address charger noise, Gen4 relies upon Cypress's established 10V S8 process technology to give a signal-to-noise ratio of 10V Tx.

While the overall performance figures rank high, one of the interesting angles to the Gen4 is the mentality behind its derivation. According to Vyas, who's vice president of Cypress's User Interface Business Unit, the device display ecosystem is fraught with challenges.

OEMs want thinner displays for their systems, but thinner displays means putting the touch sensor closer to the ITO layers of the LCD, making the sensor more susceptible to noise. The touch sensor could ask the LCD maker to reduce the noise, or the LCD maker could ask the display glass maker to put in an extra shield layer, but this costs an extra $1.

So, what to do? Cypress decided to cut all the back and forth and just take noise out of the equation. "We [as an ecosystem] can't keep complaining about display noise," said Vyas, "instead we just fixed it." With proprietary noise cancellation algorithms, which Vyas would not describe beyond hinting at techniques used in noise-cancelling headphones, Cypress's Gen4 eliminates the need for a 0.5-to 0.7-mm glass layer, as well as the associated 0.3-mm air gap to reduce the display thickness, without compromising noise performance.

Figure: Cypress's Gen4 TrueTouch's Display Armor LCD noise cancellation technology allows removal of a glass shield and associated airgap, saving up to 1 mm in display thickness.

For more on display noise the associated topic of charger noise, Cypress has produced an interesting paper called, "Investigating display and charger noise: Projected capacitance evolving," that goes into more detail.

Back to the Gen4. Other key features of the new lineup include:
Small size: Up to 40 I/Os for mobile phone applications, with support for up to four standalone CapSense button. IP-67 waterproofing support and dynamic switching between self- and mutual-capacitance sensing methods.

How soon can you get hold of one?
You'll have to get in line: The Gen4 controllers are available now only to lead customers, to which Cypress expects to deliver volume production by the end of 2011.

Packaging: The family will be available in a 44-pin 5x5 QFN with 31 sense I/Os, a 48-lead 6x6 QFN package with 35 sense I/Os, a 49-ball WLCSP package with 36 sense I/Os, and a 60-ball WLCSP package with 40 sense I/Os. The WLCSP (Wafer-Level Chip-Scale Packages) devices have a footprint of only 3.8 mm x 3.8 mm.
For more on the new Gen4 devices, go to touch.cypress.com.

Given that Cypress believes figures from DisplaySearch that the touchscreen market will grow 200% to $23 billion by 2017, they think you shouldn't mind waiting a few weeks to jump on the touchscreen bandwagon with a really good device. I'm inclined go agree with them.

What do you think?

For the latest on sensors, see:

Modern sensors greatly enhance consumer-elecronics-system performance

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