The ML4655 from Spectrum Control is a RF PIN Diode with Forward Current 10 to 40 mA, Reverse Current 10 uA, Breakdown Voltage 600 to 650 V, Thermal Resistance 7 to 15 Degree C/W, Forward Resistance 0.5 to 0.7 Ohms. Tags: Surface Mount. More details for ML4655 can be seen below.