The TRF3702 is an ultralow-noise direct quadrature modulator that is capable of converting complex input signals from baseband or IF directly up to RF. An internal analog combiner sums the real and imaginary components of the RF outputs. This combined output can feed the RF preamp at frequencies of up to 2.5 GHz. The modulator is implemented as a double-balanced mixer. An internal local oscillator (LO) phase splitter accommodates a single-ended LO input, eliminating the need for a costly external balun.