IH401A

Semiconductor April 1999 T UCT ROD ACEMEN 47 P E 7 T L 7 E P 42 OL RE 00-4 m OBS ENDED 8 1 s.co MM ions ECO pplicat p@harri R O A N ral ntap Cent : ce Call or email IH401A QUAD Varafet Analog Switch Features rDS(ON) (Typ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Ω ID(OFF) (Typ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10pA Switching Times (RL = 1kΩ) - tON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25ns - tOFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75ns Built-In Overvoltage Protection . . . . . . . . . . . . . . ±25V Charge Injection Error (Typ) into 0.01µF Capacitor . . 3mV CISS (Typ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <1pF Can Be Used for Hybrid Construction Description The IH401A is made up of 4 monolithically constructed combinations of varacitor type diode and a N-Channel JFET. The JFET itself is very similar to the popular 2N4391, and the driver diode is specially designed, such that its capacitance is a strong function of the voltage across it. The driver diode is electrically in series with the gate of the N-Channel FET and simulates a back-to-back diode structure. This structure is needed to prevent forward biasing the source-to-gate or drain-to-gate junctions of the JFET when used in switching applications. Previous applications of JFETs required the addition of diodes, in series with the gate, and then perhaps a gate-tosou...