Basestations keep getting smaller and more efficient thanks to products like the Texas Instruments TRF37017, which puts a direct up-conversion IQ modulator on the same chip with a phase-locked loop (PLL) and a wide-band voltage-controlled oscillator (VCO). This chip simplifies the local oscillator (LO) design, limits bill-of-materials (BOM) costs, and reduces board space as well as costs for new transmitter designs for basestations, point-to-point microwave transceivers, or software-defined radios. It suits any wireless technology, including GSM/EDGE, UTMS WCDMA, cdma2000, TD-SCDMA, Long-Term Evolution (LTE), and WiMAX.

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The modulator itself has a frequency range from 300 MHz to 4.8 GHz. The VCO range is similar, of course. Other critical specs include a 76-dBc adjacent-channel power ratio (ACPR) at –8 dBm for single-carrier WCDMA, an output third-order intercept point  (OIP3) of 26 dB, a 1-dB gain compression measurement (P1dB) of 11.5 dBm, a phase noise of –132 dBc/Hz, and a low noise floor of –160 dBm/Hz. The baseband inputs may be biased either internally or externally.

The PLL can be fractional or integer. The internal VCO uses internal 1/2/4/8 frequency dividers to set the desired frequency in the 300-MHz to 4.8-GHz range. Frequency control is by a three-wire serial peripheral interface (SPI). A separate control pin invokes a power-save mode to reduce power consumption while keeping the VCO locked for fast startup. The device also accepts an LO input from an external source.

The Texas Instruments TRF372017 is the first chip to integrate an IQ modulator, a PLL synthesizer, and a wideband VCO into a single package. With a frequency range of 300 MHz to 4.8 GHz, it targets basestations and other wireless infrastructure equipment.

The TRF372017 comes in a 7- by 7-mm, 48-pin quad flat no-lead (QFN) package. It costs $5.50 in 1000-unit quantities. The TRF372017EVM standalone evaluation module is available for $299. The modulator chip is also included on the DAC3283EVM evaluation module for $499.

Texas Instruments