Features

• Frequency Range: 700MHz to 6GHz
• Low Power: 2.7V to 3.6V Supply; 29.5mA
• Low LO Carrier Leakage: –43dBm at 1.8GHz
• Side-Band Suppression: –50dBc at 1.8GHz
• Output IP3: 19dBm at 1.8GHz
• Low RF Output Noise Floor: –157dBm/Hz at 30MHz Offset, P_RF = 1.8dBm, f_RF = 2.17GHz
• Sine Wave or Square Wave LO Drive
• SPI Control:
  Adjustable Gain: 19dB in 1dB Steps
  Effecting Supply Current from 9mA to 39mA
  I/Q Offset Adjust: –64dBm LO Carrier Leakage
  I/Q Gain/Phase Adjust: –61dBc Side-Band Suppressed
• 24-Lead 4mm × 4mm Plastic QFN Package

Typical Application

Description

The LTC®5589 is a direct conversion I/Q modulator designed for low power wireless applications that enables direct modulation of differential baseband I and Q signals on an RF carrier. Single side-band modulation or side-band suppressed upconversion can be achieved by applying 90° phase-shifted signals to the I and Q inputs. The I/Q baseband input ports can be either AC or DC coupled to a source with a common mode voltage level of about 1.4V. The SPI interface controls the supply current, modulator gain, and allows adjustments of I and Q gain and phase imbalance to optimize the LO carrier feedthrough and side-band suppression. The LO port can be driven with sine wave or square wave LO drive. A fixed LC network on the LO and RF ports covers 700MHz to 6GHz operating range. An on-chip thermometer can be activated to compensate for gain-temperature variations. More accurate temperature measurements can be made using an on-chip diode. In addition, a continuous analog gain control (V_CTRL) pin can be used for fast power control.