We have fabricated a single-chip coherent demodulator for MSK (minimum shift keying), i.e. FFSK (fast frequency shift keying), which is one of the most effective modulation schemes for nonlinear digital radio communication systems. Carrier and clock recovery circuits are also integrated into the same chip. The demodulator operates at a bit rate of 32 kbit/s and a carrier frequency of 455 kHz at 5 V.