7.6 A +8dBm BLE/BT transceiver with automatically calibrated integrated RF bandpass filter and −58dBc TX HD2

• Published in: 2017 IEEE International Solid-State Circuits Conference (ISSCC) pp. 136 - 137
• Main Authors: Yang, Wei, Hu, De Yong, Lam, Chun Kit, Cui, Ji Qing, Soh, Lip Kai, Song, De Cheng, Zhong, Xiao Wei, Hor, Hon Cheong, Heng, Chee Lee
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-02-2017
• Subjects: Band-pass filters; Discrete cosine transforms; Internet of Things; Radio frequency; Sensitivity; Transceivers; Voltage-controlled oscillators
• ISSN: 2376-8606
• DOI: 10.1109/ISSCC.2017.7870298

To facilitate the ubiquitous deployment of wireless sensors for Internet-of-Things (IoT) applications, highly integrated ultra-low-power (ULP) RF transceivers are essential, and numerous solutions have been proposed. These architectures address the less-stringent Bluetooth Low-Energy (BLE) standard, which depends on long intervals between advertising events to shorten the duty cycle of active operation, and have sacrificed RF performance like TX output level, sensitivity and blocking margins for ULP. Poorer sensitivity and low TX output level will decrease the coverage of IoT devices, and increased susceptibility to interferences will reduce the effectiveness of duty-cycling in BLE. Both cases will increase overall power consumption. On the other hand, conventional BT transceivers [1,2] rely on external RF components or large integrated passive devices (IPD) to deliver high RF performances at the expense of significantly higher DC power. This paper discloses a BT/BLE transceiver in a system-on-chip (SoC) to overcome these restrictions. The transceiver integrates a tunable RF bandpass filter (BPF) and co-matching network to help the RX achieve large blocking margins while withstanding +8dBm TX output level. The RX utilizes a current-reuse RF front-end to increase sensitivity and ACI margins with ULP. The direct-conversion transmitter (DCT) implements a Class-AB push-pull PA that reduces its 2 nd -harmonic (HD2) component to <;-58dBc without any calibration, thus reducing the overall SX current consumption and simplifying the RF BPF design.