1 Introduction

The CC1120 is a fully integrated singlechip radio transceiver designed for high performance at very low power and low voltage operation in cost effective wireless systems. The device is mainly intended for Industrial, Scientific, and Medical (ISM) applications and Short Range Device (SRD) frequency bands at 164 to 192 MHz, 274 to 320 MHz, 410 to 480 MHz, and 820 to 960 MHz. In many of these applications, radio transceiver ICs, such as the CC1120, are commonly powered by an external DC/DC converter to regulate down the input voltage of a system. While beneficial to the overall efficiency of the system and providing lower system current consumption, DC/DC converters may produce a ripple output that interferes with the frequency output to the transceiver’s antenna. This may raise issues when using the CC1120 or other radio IC's, for industrial settings, as the device must maintain a certain level of radiated emissions to pass FCC regulations. To mitigate this, it is beneficial to understand the functionalities that cause the undesirable behavior of sensitive circuitry.