A boundary scan circuit containing a freeze circuit and a transparency circuit that provides a capability to selectively place portions of a system logic in a sleep mode and thereby conserving power. There are two transparency circuit configurations, one that connects to an input pad cell and one that connects to an output pad cell. The circuitry in the transparency circuit is controlled in such a manner as to establish at the output of transparency circuit a known logic state to control leakage current resulting from the circuitry of the various pad cell configurations, which further conserves power during sleep mode.