The ML4674 from Spectrum Control is a RF PIN Diode with Insertion Loss 0.7 to 1 dB, Isolation 20 to 25 dB, Reverse Current 10 uA, Breakdown Voltage 600 to 650 V, Thermal Resistance 15 to 25 Degree C/W. Tags: Chip. More details for ML4674 can be seen below.