A closer look at the technology that protects your touchscreen devices from damaging ESD

Did you know that whenever you interact with the local environment, electrostatic discharges are created?

A majority of these charges go unnoticed, but the everyday use of smartphones and tablet computers has significantly increased the number of times these discharges are created. You see, whenever a touchscreen-based device is covered in a sheath or removed from a pocket, static electricity is created. While this charge might be harmless to the touch, it can discharge across the device’s screen and into the device itself. 

Still, one might think this is not really a problem. But you must consider the fact that the capacitive-touch screen display — the most common interface on touchscreen-based devices today — is most vulnerable because it provides by design a conduit to transmit wanted (control — your thumb or stylus typing) and unwanted (static electricity) signals to the most sensitive electronic elements of the device — the baseboard processor.

As a result, it is imperative that the capacitive-touch screen display be protected. Fortunately, there are circuit protection companies like Littelfuse that specialize in just this sort of technology. In fact, the company just launched a new device, called the SP1012-05WTG, which offers five times the ESD diodes in the same size footprint as a 0402-style chip. 

Specifically, it is a five-line, bidirectional, low-capacitance device designed to protect touchscreen displays from electrostatic discharge as well as the lines on SIM cards. It is the world’s smallest ESD protection array and comes with a bevy of noteworthy features:
• Most ESD protection devices per mm (2)
• Promotes high ESD immunity and superior protection 
    – ESD: IEC61000-4-2, ±15 kV
    – Lightning: IEC61000-4-5, 3 A
    – EFT: IEC61000-4-4, 40 A
• Very low dynamic resistance of 0.48 Ω
• Flexible ground connection; any I/O pad will work
• Permits back-to-back 6-V standoff

And for those looking for a list of the device’s benefits: 
• Five ESD diodes in an 0402-sized footprint (0.94 × 0.61 mm) represents a 33% space savings when compared with five discrete 0201-sized diodes, saving PCB area and cost
• ESD protection beyond the maximum rating in the IEC61000-4-2 standard gives engineers more design margin and higher end product reliability in the field
• Support for  low clamping voltages needed for protecting modern electronics filled with small-geometry ICs
• Designer friendly; permits flexible routing, connect to closest available ground
• Standoff voltages to enable protection of 95% of all interfaces

Download the SP1012 datasheet to learn more about this exciting new device, or request samples to try it out for yourself. 

If you’d like to learn more about it, or to learn more about circuit protection in general, head to Littelfuse.com