DESCRIPTION
The LT®5568-2 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 GSM, EDGE, CDMA, CDMA2000 and other systems that operate in the 850MHz to 965MHz band. It may 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.

FEATURES
■ Optimized Image Rejection for 850MHz to 965MHz
■ High OIP3: +22.9dBm at 900MHz
■ Low Output Noise Floor at 5MHz Offset:
   No RF: –159.4dBm/Hz
   POUT = 4dBm: –153dBm/Hz
■ 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: –43dBm at 900MHz
■ High Image Rejection: –52dBc at 900MHz
■ 16-Lead 4mm × 4mm QFN Package

APPLICATIONS
■ Infrastructure Tx for GSM/Cellular Bands
■ Image Reject Up-Converters for Cellular Bands
■ Low-Noise Variable Phase-Shifter for 700MHz to 1050MHz Local Oscillator Signals
■ RFID Reader