An embedded rectifier-based Built-in-Test (BIT) detection circuit for the RF integrated circuits is proposed, and charge pump rectifier is adopted to transform the RF output signal into DC signal. In this BIT circuit, low threshold voltage MOS transistor with positive substrate bias is used to act as diode to further improve the detecting sensitivity. With this BIT circuit, the minimum input testing sensitivity can be improved to -50dBm. Also, this circuit doesn't consume current and has very high operating frequency scalability. As an example 2.4GHz low noise amplifier has been verified by using this BIT detection circuit, and gain and linearity are extracted. Â© 2006 IEEE.