A Sub-100 μW RF Transmitter with 41% Global Efficiency Using Third-Harmonic Edge-Combining Technique and Class-E PA for Low-Power Biomedical Applications

In this paper, a high global efficiency OOK transmitter (TX) working at 400-460 MHz is proposed by utilizing third-harmonic edge-combining technique for low power biomedical applications. The operation frequency of the proposed TX before the third-harmonic edge-combiner (THEC) is 1/15 of the output RF frequency and 1/3 of the traditional edgecombiner-based TX. The multi-phase signals used for edge combiner (EC) are generated by a delay-locked loop (DLL) at a relative low frequency, which significantly reduces the overall TX power consumption. The TX is designed in 55-nm CMOS process with a core area of 0.02 mm2, the proposed TX consumes a DC power of 98.75 mu W under a 0.8 V supply voltage. The simulated output power is -14 dBm with 20 Mbps OOK data. The TX achieves a 41% global efficiency and a 4.94 pJ/bit energy efficiency, respectively.