A K-band on-off keying (OOK) receiver implemented in tsmcTM90 nm CMOS process is proposed. The proposed OOK receiver consists of a two-stage wideband low-noise amplifier, a single-to-differential envelop detector with RC lowpass filter and a 62.6 dB three-stage variable gain amplifier and DC offset compensation circuit. The OOK receiver achieved a sensitivity of -47.6 dBm at 600 Mbit/s data rate under a pseudo-random binary sequence 29-1 pattern. The receiver consumes a low power of 9.5 mW, which minimum average power is only 15.86 nW at the input power of -47.6 dBm. The chip area including test pads is 1 × 0.81 mm2.