Abstract: A direct-conversion type wireless receiver includes a pair of mixers for frequency-converting a radio signal received from an antenna into a base band signal by local signals having different phases; a first amplification circuit for amplifying the base band signal up to a demodulation level; a second amplification circuit provided between the mixer and the first amplification circuit; and a variable current circuit including a multi-stage current mirror to add a current 2n times as high as a reference current. The wireless receiver further includes a control unit configured to correct a DC offset of the mixer by allowing a current to flow into the second amplification circuit from the variable current circuit, based on an output of the first amplification circuit, and a capacitor connected between a gate and a source of a PchMOSFET which allows the reference current to flow therethrough.

Abstract: A direct-conversion type wireless receiver includes a pair of mixers for frequency-converting a radio signal received from an antenna into a base band signal by local signals having different phases; a first amplification circuit for amplifying the base band signal up to a demodulation level; a second amplification circuit provided between the mixer and the first amplification circuit; and a variable current circuit including a multi-stage current mirror to add a current 2n times as high as a reference current. The wireless receiver further includes a control unit configured to correct a DC offset of the mixer by allowing a current to flow into the second amplification circuit from the variable current circuit, based on an output of the first amplification circuit, and a capacitor connected between a gate and a source of a PchMOSFET which allows the reference current to flow therethrough.

Abstract: A single or a plurality of semiconductor chips or thin film elements which are bare or passivated to a minimum extent are housed in an enclosure member formed by drawing into the shape of a tray from a laminate consisting of an insulation layer and a first and second conductive layers formed on opposite sides, respectively, of the insulation layer. The enclosure member has a concavity having a substantially flat bottom and circumferential edge. There are provided on the inner surface of the concavity as extended to the circumferential edge, wiring conductors which are destined for connecting the terminal electrodes of the semiconductor chip or the like to the terminal electrodes corresponding to electronic parts on a circuit board, while the outer surface of the concavity is held at the ground potential to form an electromagnetic shield. The semiconductor chip or the like is connected to one end of the wiring conductor by the wire bonding process and resin-molded in the concavity.