The MAX2021 low-noise, high-linearity, direct upconversion/downconversion quadrature modulator/demodulator is designed for RFID handheld and portal readers, as well as single and multicarrier 650MHz to 1200MHz GSM/EDGE, cdma2000®, WCDMA, and iDEN®base-station applications. Direct conversion architectures are advantageous since they significantly reduce transmitter or receiver cost, part count, and power consumption as compared to traditional IF-based double conversion systems.In addition to offering excellent linearity and noise performance, the MAX2021 also yields a high level of component integration. This device includes two matched passive mixers for modulating or demodulating in-phase and quadrature signals, two LO mixer amplifier drivers, and an LO quadrature splitter. On-chip baluns are also integrated to allow for single-ended RF and LO connections. As an added feature, the baseband inputs have been matched to allow for direct interfacing to the transmit DAC, thereby eliminating the need for costly I/Q buffer amplifiers.The MAX2021 operates from a single +5V supply. It is available in a compact 36-pin TQFN package (6mm x 6mm) with an exposed pad. Electrical performance is guaranteed over the extended -40°C to +85°C temperature range.ApplicationsCable Modem Termination Systems (CMTS)Digital and Spread-Spectrum Communication SystemsFixed Broadband Wireless AccessGSM 850/GSM 900 EDGE Base StationsMicrowave LinksMilitary SystemsPredistortion Transmitters and ReceiversRFID Handheld and Portal ReadersSingle and Multicarrier cdmaOne™ and cdma2000® Base StationsSingle and Multicarrier WCDMA 850 Base StationsVideo-on-Demand (VOD) and DOCSIS® Compliant Edge QAM ModulationWiMAX Transmitters and Receivers