LT5558 - 600MHz to 1100MHz High Linearity Direct Quadrature Modulator

The LT5558 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. It may also be confi gured as an image reject upconverting 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 doublebalanced 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 which produce the LO drive for the mixers. The supply voltage range is 4.5V to 5.25V.

Features
  • Direct Conversion from Baseband to RF
  • High OIP3: + 22.4dBm at 900MHz
  • Low Output Noise Floor at 20MHz Offset:   No RF: –158dBm/Hz   POUT = 4dBm: –152.7dBm/Hz
  • Low Carrier Leakage: –43.7dBm at 900MHz
  • High Image Rejection: –49dBc at 900MHz
  • 3 Channel CDMA2000 ACPR: –70.4dBc at 900MHz
  • Integrated LO Buffer and LO Quadrature Phase Generator
  • 50Ω AC-Coupled Single-ended LO and RF Ports
  • High Impedance Interface to Baseband Inputs with 2.1V Common Mode Voltage
  • 16-Lead QFN 4mm × 4mm Package
Typical Application
LT5558 Typical Application
LT5558 Typical Application
Applications
  • RFID Single-Sideband Transmitters
  • Infrastructure TX for Cellular and ISM Bands
  • Image Reject Up-Converters for Cellular Bands
  • Low-Noise Variable Phase-Shifter for 600MHz to 1100MHz Local Oscillator Signals
  • Microwave Links
Packaging
LT5558 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT5558EUF#PBF4x4 QFN-16E$7.60$5.35
LT5558EUF#TRPBF4x4 QFN-16E$5.40
Demo Boards
Part NumberDescriptionPrice
DC1017ALT5558EUF | 600-1100MHz I-Q Modulator w/ Hi-Z BB Rin, Vcm = 2.1V$125.00
Datasheet
Application Note
Reliability Data
Press Release
CAD Symbol
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LT5558 Footprints and Symbols