LT5568-2 - GSM/EDGE Optimized, High Linearity Direct Quadrature Modulator

The LT5568-2 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. 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
  • 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
Typical Application
LT5568-2 Typical Application
LT5568-2 Typical Application
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
Packaging
LT5568-2 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT5568-2EUF#PBF4x4 QFN-16E$7.60$5.35
LT5568-2EUF#TRPBF4x4 QFN-16E$5.45
Demo Boards
Part NumberDescriptionPrice
DC1178ALT5568-2EUF | 900MHz GSM/EDGE Optimized I/Q Modulator$125.00
Datasheet
Application Note
CAD Symbol
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LT5568-2 Footprints and Symbols