The LTC5598 is a direct I/Q modulator designed for high performance wireless applications, including wireless infrastructure. It allows direct modulation of an RF signal using differential baseband I and Q signals. It supports point-to-point microwave link, GSM, EDGE, CDMA, 700MHz band LTE, CDMA2000, CATV applications and other systems. It may also be configured as an image reject upconverting mixer, by applying 90 phase-shifted signals to the I and Q inputs.
The I/Q baseband inputs consist of voltage-to-current converters that in turn drive double-balanced mixers. The outputs of these mixers are summed and applied to a buffer, which converts the differential mixer signals to a 50 Ohm single-ended buffered RF output. The four balanced I and Q baseband input ports are intended for DC coupling from a source with a common-mode voltage level of about 0.5V. The LO path consists of an LO buffer with single-ended or differential inputs, and precision quadrature generators that produce the LO drive for the mixers. The supply voltage range is 4.5V to 5.25V, with about 168mA current.