Design of wide band OOK transmitter for biomedical applications

This paper presents a low power high data rate telemetry system for biomedical applications, such as neural recording systems for freely moving animals or wireless capsular endoscopy. Presented system operates in 4 GHz frequency band. It makes use of OOK modulation and offers a very high data rate, well above 100 Mbits/s. Presented wideband transmitter was implemented in 180 nm CMOS process with an area of 0.42×0.8 mm² and consumes 1.2 mW of power when operating with 20 Mbits/s data rate at a distance of 10 m. All of the inductors were integrated on the transmitter´s silicon die, so the only external components are the power supply bypass capacitors. Presented transmitter uses a complementary Colpitts oscillator, what enables it to operate on a single 1.5 V battery. The RF Class E power amplifiers makes use of cascode topology to avoid MOS transistor gate oxide breakdown and the performance degradation due to hot carrier effects. The control logic of the transmitter includes FEC encoder, bit interleaver and scrambler. It was implemented in an ulta-low power 65 nm FPGA.