A 250-Mb/s On-Chip Capacitive Digital Isolator With Adaptive Frequency Control

In this letter, a fully integrated capacitive-coupled digital isolator is proposed. By utilizing the adaptive carrier frequency control (AFC) scheme, the power consumption at low data rate is significantly reduced while maintaining a maximum data rate of 250 Mb/s. The on-chip isolation capacitor provides 2.5-kVRMS isolation rating with compact silicon area. The transmitter (TX) and receiver (RX) are fabricated in a 180-nm CMOS technology. Measurement results show that the transmitter consumes 0.6 and 1.15 mA at 100 kb/s and 250 Mb/s, respectively.