The MC33169 is a support IC for GaAs Power Amplifier Enhanced FETs used in handheld telephones such as GSM and PCS. This device provides negative voltages for full depletion of Enhanced MESFETs as well as a priority management system of drain switching, ensuring that the negative voltage is always present before turning "on" the Power Amplifier. Additional features include an idle mode input and a direct drive of the NChannel drain switch transistor. This product is available in a 4.0 V version intended for control of the RF Power Amplifier in GSM, DCS1800 and PCS applications.