The MB54609 is an intermediate-frequency (IF) quadrature modulator IC incorporating a 1.0-GHz up-converter optimized for use in digital mobile telecommunication systems such as GSM and PDC (Personal Digital Cellular). The MB54609 incorporates a quadrature modulator for IF modulation, a transmission up-convert mixer, and a F/F type phase shifter as well, capable of handing IFs in a broad band. In addition, the MB54609 operates at a low power supply voltage of 3.0 V and a low power supply current of 18 mA (both as typical values), contributing to saving the power consumption of the device.