LT5571 - 620MHz - 1100MHz High Linearity Direct Quadrature Modulator

The LT5571 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 RFID, 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 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 at 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 from Baseband to RF
  • High Output: –4.2dB Conversion Gain
  • High OIP3: 21.7dBm at 900MHz
  • Low Output Noise Floor at 20MHz Offset: No RF: –159dBm/Hz POUT = 4dBm: –153.3dBm/Hz
  • Low Carrier Leakage: –42dBm at 900MHz
  • High Image Rejection: –53dBc at 900MHz
  • 3-Ch 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 DC Interface to Baseband Input with 0.5V Common Mode Voltage
  • 16-Lead QFN 4mm × 4mm Package
Typical Application
LT5571 Typical Application
LT5571 Typical Application
Applications
  • RFID Interrogators
  • GSM, CDMA, CDMA2000 Transmitters
  • Point-to-Point Wireless Infrastructure Tx
  • Image Reject Up-Converters for Cellular Bands
  • Low-Noise Variable Phase-Shifter for 620MHz to 1100MHz Local Oscillator Signals
Packaging
LT5571 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT5571EUF#PBF4x4 QFN-16E$7.05$4.95
LT5571EUF#TRPBF4x4 QFN-16E$5.01
Demo Boards
Part NumberDescriptionPrice
DC944ALT5571EUF | 900MHz I/Q Modulator w/ Hi-Z & 0.5VDC Bias$125.00
Datasheet
Application Note
Reliability Data
Press Release
CAD Symbol
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LT5571 Footprints and Symbols