RF switch and attenuator core — PIN diode in SC-79
The Infineon BAR6502VH6327XTSA1 is a single PIN diode designed for RF switching, attenuation, and limiter circuits up into the low-GHz range. Its 900 mOhm series resistance at 10 mA forward current and 100 MHz sets the insertion loss floor in a shunt or series switch leg, while the 0.8 pF capacitance at 3 V reverse bias determines the off-state isolation. Rated for a peak reverse voltage of 30 V and a continuous forward current of 100 mA, the part handles the signal levels typical of 50-ohm RF front ends without compression. The 250 mW power dissipation ceiling is the thermal limit in the SC-79 body — keep the average RF power below that for reliable operation.
Parametric fit for RF front-end designs
The 900 mOhm resistance at 10 mA forward bias is the on-state loss the design sees in a series switch. For a shunt configuration, the same resistance sets the insertion loss when the diode is forward-biased to ground. The 0.8 pF capacitance at 3 V reverse bias gives an off-state impedance of about 200 ohms at 1 GHz — adequate isolation for many T/R switch and step-attenuator applications. The SC-79 (SOD-523) package fits into compact RF front-end modules where board area is tight.