Integrated MIMO Transceiver
The direct-conversion receivers have state-of-the-art noise figure and linearity and require no external components with the exception of baluns. The complete RF sub-system integrates autonomous AGC loops, DC offset corrections, and quadrature calibrations, thus eliminating the need for high-speed interaction with the BBP processor.
Two high dynamic range ADCs digitize the received signal. Decimation and channel filters produce a 12-bit output signal at a sample rate determined by the bandwidth mode. The transmit path takes 12-bit input data and interpolates before converting to the analog domain and upconverting to the carrier frequency. The highly linear transmit path has excellent spectral purity with side-band noise less than -130 dBc/Hz at 8 MHz offset and offers EVM of -38 dB at 0 dBm output power. The transmit power is detected by an accurate power detector with a range of more than 50 dB in 0.25 dB steps. A single factory measurement calibrates the detector.
The reference frequency may be provided by an external reference or via an internal digitally controlled crystal oscillator (DCXO) with a resolution of 0.012 ppm. Using the built-in state machine to control the device, the AD9356 may be easily controlled in TDD, HFDD, or, if two devices are used, FDD modes. One three-input internal auxiliary ADC and two auxiliary DACs are available for system monitoring and control. Four general purpose I/Os are also included and can be register programmed or automatically sequenced by a user-defined state machine. Mode control is via a 4-wire serial port and two control signals. A single 3.3V supply powers the AD9356 with on-chip LDOs providing all other required supplies. The AD9356 package is a 10 x 10 mm, 144-ball BGA.