5MHz to 1600MHz High Linearity Direct Quadrature Modulator

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 50Ω 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.

Applications

* Point-to-Point Microwave Link

* Military Radio

* Basestation Transmitter GSM/EDGE/CDMA2K

* 700MHz LTE Basestation Transmitter

* Satellite Communication

* CATV/Cable Broadband Modulators

* 13.56MHz/UHF RFID Modulator

* Frequency Range: 5MHz to 1600MHz

* High Output IP3:

* +27.7dBm at 140MHz

* +22.9dBm at 900MHz

* Low Output Noise Floor at 6MHz Offset:

* No Baseband AC Input: –161.2dBm/Hz

* POUT = 5.5dBm: –160dBm/Hz

* Low LO Feedthrough: –55dBm at 140MHz

* High Image Rejection: –50.4dBc at 140MHz

* Integrated LO Buffer and LO Quadrature Phase Generator

* 50Ω Single-Ended LO and RF Ports

* >400MHz Baseband Bandwidth

* 24-Lead QFN 4mm × 4mm Package

* Pin-Compatible with Industry Standard Pin-Out

* Shut-down Mode