A multiband LTE SAW-less modulator with -160dBc/Hz RX-band noise in 40nm LP CMOS

In FDD cellular standards, the transmitter’s out of-band noise leaks into the receive band due to the finite duplexer TX to RX isolation. If this noise is not low enough, a SAW filter is needed before the Power Amplifier to preserve the RX sensitivity. Out-of-band noise is also an important concern for coexistence of cellular transmitters with standards like GPS, WLAN and/or WiMAX on the same smart phone, a very common scenario nowadays. The SAW-less RX-band noise challenge becomes even more acute in the Long-Term Evolution (LTE) standard [1] where transmitters will need to operate in multiple FDD bands, using wider channel bandwidths and higher Peak-to-Average Power Ratios (PAPR).