The ML4668 from Spectrum Control is a RF PIN Diode with Insertion Loss 0.5 to 0.7 dB, Isolation 20 to 25 dB, Reverse Current 10 uA, Breakdown Voltage 150 to 180 V, Thermal Resistance 15 to 25 Degree C/W. Tags: Chip. More details for ML4668 can be seen below.