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LT5518 - 1.5GHz - 2.4GHz High Linearity Direct Quadrature Modulator

The LT5518 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 configured as an image reject up-converting mixer, by applying 90° phase-shifted signals to the I and Q inputs. The high impedance 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 balanced I and Q baseband input ports are intended for DC coupling from a source with a common mode voltage level of about 2.1V. 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 High Input Impedance Version of the LT5528 Direct Conversion to 1.5GHz - 2.4GHz High OIP3: 22.8dBm at 2GHz Low Output Noise Floor at 20MHz Offset: No RF: -158.2dBm/Hz POUT = 4dBm: -152.5dBm/Hz 4-Ch W-CDMA ACPR: -64dBc at 2.14GHz Integrated LO Buffer and LO Quadrature Phase Generator 50Ω AC-Coupled Single-Ended LO and RF Ports Low Carrier Leakage: -49dBm at 2GHz High Image Rejection: 40dB at 2GHz 16-Lead QFN 4mm × 4mm Package Typical Application

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

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