A Wideband Transmitter for LTE-A HPUE using CIM3 Cancellation

Abstract

A wide-band direct conversion transmitter (DCT) based on a compact voltage-mode passive modulator architecture successfully fulfilling the stringent power and linearity requirements of the LTE-A Band 41 high-power user equipment (HPUE) standard is presented. The voltage-mode architecture is low noise and power efficient, but generates a harmonic-rich spectrum at the modulator output, which through inter-modulation in the PA driver, creates counter-inter-modulation (CIM) products at the transmitter output. It is demonstrated that partial cancellation of CIM3 can be achieved by careful analysis and optimization of the multiple CIM3 mechanisms. This transmitter achieves -54dBc CIM3 at 3.3dBm output power, while supporting 60MHz bandwidth LTE-A CCA and covering a wide frequency range of 2.3-3.6GHz. The die area of the HPUE transmitter is 0.33mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> in 40nm CMOS.