A 0.13µm CMOS ΔΣ PLL FM transmitter

A short range FM transmitter is presented. It uses an architecture where the output frequency of a phase locked loop (PLL) is modulated by varying the division number of the feedback divider, using the 1-bit output of a ΔΣ ADC. The measured total harmonic distortion (THD) plus noise is less than 1% at 75 kHz deviation. The transmitter is fully integrated in a 0.13µm CMOS process and the core area is 0.24 mm 2 . The current consumption is 4.4mA from a 1.2V supply.