13.3 A 10mW Bluetooth Low-Energy transceiver with on-chip matching

Wireless sensor nodes present a difficult compromise at the system level between low power consumption, interference resilience and ease/size of the application. Recent low-power designs employ receiver architectures in which the LO runs at or below the received frequency (in TX at the required RF frequency). These architectures facilitate LO generation and distribution at a favorably low frequency, but cause a systematic, hard-to-circumvent susceptibility to out-of-band blockers in RX [1] and pulling in TX [1,2]. The presented Bluetooth Low-Energy (BLE) transceiver, as shown in Fig. 13.3.1, was purposely designed with a classic double-frequency VCO architecture to avoid these inherent weaknesses, but still significantly reduces the power consumption of designs of the same architecture [3,4]. In order to ease application, an on-chip DC-DC converter supports battery operation between 0.9V and 3.3V. An on-chip T/R switch, RX balun and impedance matching allow 50Ω chip antennae to be used directly on the single-ended RFIO pin, without the need for external RF filtering. This enables minimum-sized modules and a fast time-to-market.