Powered by a single supply between 2.7V and 3.6V, the LTC5589 modulator uses only 29.5mA of current, consuming 50% less power than other solutions. The new modulator features excellent sideband suppression performance of -50dBc and carrier leakage of -43dBm (typical) without calibration. Sideband and carrier leakage can be further enhanced using the chip's built-in tuning functions via the SPI bus to improve suppression to over -60dBc and -60dBm, respectively. In addition, the device has a very low output noise floor of -158.8dBm/Hz, which, combined with an OIP3 of 19dBm, results in superior transmission performance.
The LTC5589 supports both narrowband and wideband transmitters. Its baseband bandwidth reaches up to 92 MHz with a flat gain of ±1 dB, providing 184 MHz of RF bandwidth up to 1.8 GHz. Combined with low power consumption and robust performance, the device is suitable for a wide range of demanding applications such as radio and wireless communications. These include broadband modems, femtocell and picocell broadband wireless access, portable audio systems and wireless microphones, portable broadband radios, unlicensed radios, train communications, software-defined radios, portable RF test equipment, low-power microwave repeaters and return systems, telemetry radios, and satellite modems.
    Previous zero-IF modulators exhibit excessive carrier leakage and very poor sideband suppression, resulting in poor error vector magnitude (EVM) and adjacent channel power ratio (ACPR). Calibration is complex and relies on the digital tuning algorithms in the FPGA baseband using external DACs. Resolution adjustment is typically limited. The LTC5589 can adjust the phase and amplitude of the I and Q channels, which affect sideband suppression. The device also offers adjustments for DC offset balance, which affects carrier leakage. With integrated calibration controlled via the serial port, the LTC5589 simplifies calibration and is cost-effective to implement.
The LTC5589's gain can be set via the chip's integrated serial port. A coarse gain control provides 1dB steps, along with a fine-tuning gain control in 0.1dB increments. The total gain ranges from -19dB to 0dB. Changing the modulator gain affects the device's current draw, which varies from 9mA to 39mA. The device can then be put into a low-power mode with slightly reduced performance and gain, as needed for specific applications. Once set, the gain can be automatically compensated by activating the chip's integrated temperature correction.    
The LTC5589 is available in 4mm x 4mm plastic QFN packages, providing a compact solution. The junction temperature range is -40°C to 105°C. The device has a pin for TDD or pulse burst transmitter operation. When disabled, the LTC5589 conserves power by consuming 0.6 μA, typical standby current. The modulator can be turned on with full quadrature accuracy in 350 ns. Its starting price is $4.45 per unit for orders of 1,000 units and is available in manufacturing quantities.

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