Four-transmit four-receive RF-sampling transceiver for single-band TDD

29-05-2020 | Texas Instruments | Subs & Systems

The Texas Instruments AFE79xx is a family of high performance, wide bandwidth multi-channel transceivers, combining four RF sampling transmitter chains, four RF sampling receiver chains, and up to two RF sampling digitising auxiliary chains (feedback paths). The high dynamic range of the transmitter and receiver chains assists the device to generate and receive 3G, 4G, and 5G signals from wireless base stations. In contrast, the wide bandwidth ability of the devices is intended for multi-band 4G and 5G base stations.

Each receiver chain comprises a 25dB range DSA, followed by a 3GSPS ADC (analog-to-digital converter). Each receiver channel includes an analog peak power detector and several digital power detectors to assist an external or internal autonomous automatic gain controller, and RF overload detectors for device reliability protection. The single or dual DDCs offer up to 600MHz of combined signal BW. In TDD mode, the receiver channel can be configured to dynamically switch between the traffic receiver (TDD RX) and wideband feedback receiver (TDD FB), with the ability to re-use the same analog input for both purposes.

Each transmitter chain comprises a single or dual DUCs supporting up to 1200-MHz combined signal bandwidth. The output of the DUCs drives a 12GSPS DAC with a mixed-mode output option to enhance 2nd or 3rd Nyquist operation. The DAC output incorporates a variable gain amplifier (TX DSA) with 40dB range and 1dB analog and 0.125dB digital steps.

The feedback path includes a 25dB range DSA driving a 3GSPS RF sampling ADC, followed by a DDC with up to 1200MHz bandwidth.

By Natasha Shek