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LT5528 - 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator

The LT5528 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 PHS, GSM, EDGE, TD-SCDMA, CDMA, CDMA2000, W-CDMA and other systems. It may also be confi gured as an image reject up-converting 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 an on-chip RF transformer, which converts the differential mixer signals to a 50Ω single-ended 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 input, and precision quadrature generators that produce the LO drive for the mixers. The supply voltage range is 4.5V to 5.25V.

Features Direct Conversion to 1.5GHz to 2.4GHz High OIP3: 21.8dBm at 2GHz Low Output Noise Floor at 5MHz Offset: No RF: –159.3dBm/Hz POUT = 4dBm: –151.8dBm/Hz 4-Ch W-CDMA ACPR: –66dBc at 2.14GHz Integrated LO Buffer and LO Quadrature Phase Generator 50Ω AC-Coupled Single-Ended LO and RF Ports 50Ω DC Interface to Baseband Inputs Low Carrier Leakage: –42dBm at 2GHz High Image Rejection: 45dB at 2GHz 16-Lead QFN 4mm × 4mm Package Typical Application

Applications Infrastructure Tx for DCS, PCS and UMTS Bands Image Reject Up-Converters for PCS and UMTS Bands Low-Noise Variable Phase-Shifter for 1.5GHz to 2.4GHz Local Oscillator Signals Packaging

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