LT5572 - 1.5GHz to 2.5GHz High Linearity Direct Quadrature Modulator

The LT5572 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 confi gured 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 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
  • Direct Conversion from Baseband to RF
  • High Output: –2.5dB Conversion Gain
  • High OIP3: +21.6dBm at 2GHz
  • Low Output Noise Floor at 20MHz Offset:   No RF: –158.6dBm/Hz   POUT = 4dBm: –152.5dBm/Hz
  • Low Carrier Leakage: –39.4dBm at 2GHz
  • High Image Rejection: –41.2dBc at 2GHz
  • 4-Channel W-CDMA ACPR: –67.7dBc at 2.14GHz
  • Integrated LO Buffer and LO Quadrature Phase Generator
  • 50Ω AC-Coupled Single-Ended LO and RF Ports
  • High Impedance DC Interface to Baseband Inputs with 0.5V Common Mode Voltage
  • 16-Lead QFN 4mm × 4mm Package
Typical Application
LT5572 Typical Application
LT5572 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 2.5GHz Local Oscillator Signals
Packaging
LT5572 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT5572EUF#PBF4x4 QFN-16E$7.05$4.95
LT5572EUF#TRPBF4x4 QFN-16E$5.05
Demo Boards
Part NumberDescriptionPrice
DC945ALT5572EUF | 2GHz I/Q Modulator w/ HiZ + 0.5VDC Bias Demo Bd.$125.00
Datasheet
Application Note
Reliability Data
CAD Symbol
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AN99 - LT5528 WCDMA ACPR, AltCPR and Noise Measurements
R409 - Reliability Data
LT5572 Footprints and Symbols