This application note introduces the application of LC filters for mobile phone LCD and camera links. The mobile phone is a compact, small device, which radiates high power, and needs to have a very good sensitivity for signal reception. This functional conflict generates an EMI issue, which can be addressed by filtering.
Mobile phones face a functional conflict between high-power radiation and the need for high sensitivity, leading to Electromagnetic Interference (EMI) issues. This document explains how digital signals from baseband processors can act as noise sources or victims of EMI, particularly affecting the reception of GSM and W-CDMA bands.
To address these interference problems on noisy digital links like LCD and camera buses, STMicroelectronics developed specific LC filters. The note details three filter types (EMIF10-LCD02F3, EMIFO8-LCD04M16, and EMIF10-LCDO3F3) that offer high bandwidth to maintain signal integrity while providing significant attenuation at mobile phone reception frequencies.
The filter needs a bandwidth in the range of 200 MHz.
The filter must attenuate frequencies from 869 MHz to 2.17 GHz.
This LC filter provides an attenuation of -35 dB or more on the RX band.