TI’s single-chip direct down conversion architecture reduces component count by 75%
( 01 Jan 2008 )
Texas Instruments has introduced a monolithic, high-linearity quadrature demodulator for direct down conversion applications. This device reduces the component count of the receive signal chain in 3G base stations by at least 75%, compared to superheterodyne architectures. The TRF3710 demodulator improves the RF receive signal chain by integrating all the devices required to go directly from RF to baseband onto one chip.
The TRF3710 is optimized for use in direct down-conversion architectures where space and cost savings are key requirements. It is said to be the first RF device in the industry to integrate a baseband filter that is software-programmable with 1-dB corner frequency, which can continuously cover signal bandwidths of 615 kHz (single carrier CDMA2000) to 1.92 MHz (single WCDMA carrier).
The device also includes a programmable gain amplifier with 24-dB of gain range in 1-dB increments, and an ADC driver that allows for direct connection to the ADC. When compared to two-stage superheterodyne architectures, the TRF3710 significantly reduces overall complexity in the system by eliminating many of the receive signal chain components, including filters, mixers, a phase-locked loop (PLL) or voltage-controlled oscillator (VCO), RF and baseband amplifiers.
