Case Study: EMC and USB Compliance in a Tablet PC

The block diagram above shows a very typical application (Tablet PC), which supports numerous interfaces. The EMI / RFI compliance while also staying in compliance with the USB 2.0 specification is addressed by the usage of an LFC Semiconductor Active EMI reduction IC with SAϕIC™ technology (LX308) at the clock source of the ASIC (MCU). This IC is subsequently replaced by a 1st-Gen Active EMI reduction IC from a competitor, configured to achieve comparable EMI/RFI benefits and the comparative results of
1) EMI compliance testing
2) USB compliance testing
are presented below.

LX308 Settings

Vdd Input Frequency Deviation Modulation Rate Dynamic Current
3.3V 24 MHz 26.4 KHz 93.77 KHz 4.35mA

LX308 with SAϕIC™ technology.

EMC Chamber Scan