Design of a Multi-band FSK Transmitter in 0.18-um CMOS Process

A fully integrated low-power transmitter suitable for high data rate wireless telemetry that can operate in the license-free ISM frequency bands mainly include 400 MHz, 900 MHz, and 2.4 GHz. The three bands include ISM 433/868/915 MHz, 2.4GHz, and MICS 402-405 MHz. Frequency-shift keying (FSK) modulation format is supported with multideviation frequency ranges from 714 kHz to 3.2 MHz. The main analog building blocks of the transmitter include an analog modulator, an analog polyphase filter, a wide-band mixer, a frequency synthesizer with inductorless VCO, and a power amplifier driver. In these blocks, the mixer and VCO architectures are newly proposed. There is no inductor used for the purpose of saving chip area.n actual measurement, when operating in the 400 MHz band, the transmitter consumes.9 mA with 1.5-V power supply, the output power is -12 dBm, and the FSK errors 13.88%. The P1dB of the mixer is -3.9 dBm, the IMRR is -33.3 dBc, and the LO leakages -28.5 dBc. Also, when operating in the 900 MHz band, the transmitter consumes1.7 mA with 1.8-V supply voltage, the output power is -14.5 dBm, and the FSK error is4.68%. The P1dB of the mixer is -2.8 dBm, the IMRR is -40 dBc, and the LO leakages -33.8 dBc. In the 2.4 GHz band, the transmitter consumes 12 mA with 1.8-V supplyoltage, the output power is -19.5 dBm, and the FSK error is 15.38%. The P1dB of theixer is -3.1 dBm, the IMRR is -36.2 dBc, and the LO leakage is -37.4 dBc. The chip wasmplemented in a 0.18-um TSMC CMOS 1P6M process and occupies 1:6 £ 1:9 mm^2.