Under the Compound Semiconductor Materials on Silicon (COSMOS) DARPA program, Northrop Grumman Aerospace Systems (NGAS) has developed an advanced heterogeneous integration technology to intimately integrate compound semiconductor (CS) devices and circuits on CMOS/SiGeBiCMOS wafers. The integration approach is based on a direct face-to-face bonding between pre-fabricated InP chiplets and Si wafers. The heterogeneous integration process is compatible with any semiconductor technology. This integration enables significant improvement in dynamic range and bandwidth of high performance mixed signal circuits. In this paper we describe the integration approach and present two demonstration circuits.