This paper presents various low power, compact, low insertion-loss sensors with digitized ADC output and digitally controlled actuation methods for on-chip characterization and healing of a mm-Wave power amplifier. We demonstrate low insertion loss (0.4dB) RF sensors which measure true input and output power in presence of load variations and very lowheadroom (10-30mV) DC sensors with built-in regulators and thermal sensors as methods for measuring PA efficiency. All sensor outputs are digitized by a SAR-based ADC for communication with a central digital core. The paper also presents digitally controlled combiner tuning and PA bias actuation. The circuits are implemented in 45 nm SOI CMOS and enable full on-chip digitally controlled characterization and actuation of the PA with a power overhead of less than 6%.