Semtech today announced the EClamp 2340C, a protection device designed specifically to safeguard high resolution colour LCD screens in cell phones from damage or upset caused by electromagnetic interference (EMI), radio-frequency interference (RFI) and electrostatic discharge (ESD).
In many designs, especially clamshell-style flip phones, the colour LCD connects to the baseband controller via a ribbon-like PCB that can act as an antenna for radiating EMI/RFI or for conducting ESD events, all of which can disrupt or damage the baseband controller circuitry. To comply with international protection regulatory standards, a typical design will incorporate low pass RC filters to suppress EMI while TVS diodes are used for ESD protection. The EClamp2340C provides these functions for up to 10 data lines — replacing up to 40 discrete components.
The EClamp2340C is the newest member of the EMIClamp family of protection products. It is packaged in a 25-bump 2.6 x 2.6 x 0.75 mm flip chip package for smallest possible size and height, reduced weight, and improved electrical performance.
“Adding a color screen to a device has always meant a high component count was necessary to meet EMI protection standards, but the EClamp2340C gives designers a new tool to dramatically reduce the space needed for this protection,” said Tom Dugan, Semtech marketing manager for protection products. “The flip chip package enhances the board-space advantage of the EClamp2340C and allows us to showcase a Semtech process advantage that makes this packaging better suited for PCB assembly.”
The EClamp2340C features a breakthrough Semtech-designed back coating that improves flip chip durability. A proprietary, non-conductive coating reduces the potential for chipping during wafer sawing, and prevents micro-cracks that can occur during automated pick and place operations. The coating can also be marked, making it easier for optical pick and place equipment to orient the device.
The EClamp2340C supports 10 data lines with each data line containing a low pass RC filter network flanked by TVS diodes at either end. A series resistor value of 100 Ohms and a capacitance value of 18pF are used to achieve 25dB minimum attenuation from 800MHz to 3GHz for each pi-configured filter. The device’s low capacitance means the EClamp2340C can be used on next-generation LCD displays with clock frequencies in excess of 12MHz. The TVS diodes are designed to suppress ESD surges in excess of the IEC 61000-4-2, Level 4 requirements of +/-8kV contact and +/-15kV air discharge.
Key Features of the EClamp2340C
– Low capacitance: can be used on next-generation, high resolution color LCD screens
– Integrated solution: replaces up to 40 discrete components
– Back coat: increases durability of flip chip during manufacturing process
– Small size: easy to use when PCB space is limited
– Low clamping voltage: higher reliability; less stress on protected IC during ESD events
– High (greater than 25dB) attenuation of EMI signals in the cellular bands
– Higher reliability: exceeds IEC 61000-4-2, Level 4 ESD standards (+/- 8kV contact, +/-15kV air)
– Flexibility: the EClamp2340C can be used in all high-speed I/O port applications, including keypads, signal control lines, and chip-to-chip data lines.
Pricing and Availability
The EClamp2340C.WC is available immediately in production quantities and is priced at $0.68 each in 3,000-piece reels. Semtech offers comprehensive design assistance, including field- and factory-based support.