Analog Devices FMCOMMS1-EBZ

WINLAB – Rutgers University

Date : April 22, 2013

Authors :

Prasanthi Maddala, prasanthi.m@gmail.com

Key Features

Software tunable across wide frequency range (400MHz to 4GHz)

125MHz channel bandwidth (250MSPS ADC, 1GSPS (1230MSPS) DAC)

RF section bypass for baseband sampling

Phase and frequency synchronization on both transmit and receive paths

Supports MIMO radio, with less than 1 sample sync on both ADC and DAC

Common I2C access for all device registers

Block Diagram

Transmit Path Key Components

- AD9122 Dual, 16-Bit, 1200 MSPS, TxDAC+® Digital-to-Analog Converter with offset, phase and gain compensation.

- ADL5375 400 MHz to 6 GHz Broadband Quadrature Modulator.

- ADF4351 Wideband Synthesizer with Integrated VCO (35MHz to 4400MHz).

- ADL5602 50 MHz to 4.0 GHz RF/IF Gain (20dB) Block.

FPGA Interface

- dac_data_out[15:0] : interleaved I/Q data from the FPGA to the DAC

- dac_clk_out : DCI input to the DAC, reference bit used to generated DDR clock for data sampling in the DAC. I DAC data should correspond to DCI high and Q DAC data to DCI low.

- dac_frame_out : used for DAC FIFO reset

- dac_clk_in : clk input to the FPGA (comes from AD9523). This clock is used to send data out to the DAC and to generate dac_clk_out (same rate).

Transmit Bandwidth

Transmit bandwidth can be as high as 250 MHz, depending on the flatness of ADL5602 and ADL5375 that works for your application

With a sampling rate of 1230MSPS, AD9122 can support a bandwidth of 600MHz (300MHz ?)

Clocking Key Components

- AD9548 Quad/Octal Input Network Clock Generator/Synchronizer (1Hz to 750MHz)

- AD9523-1 Low Jitter Clock Generator (1MHz to 1GHz) with 14 Outputs.

FPGA Interface/Inputs

- ref_clk_out : reference clock from the FPGA to AD9548.

- crystal oscillators : 19.2MHz oscillator connected to AD9548

50 – 122.88MHz VC oscillator connected to AD9523

Clocking in the default reference design

- ref_clk_out = 30MHz. This is cleaned up (from a jitter standpoint) and sent to AD9523

- AD9523 takes this, and creates

491.52 MHz for the DAC sample rate

245.76 MHz for the ADC sample rate

122.88 MHz for the reference clocks for the LO PLLs.

Receive Path

Key Components

- ADL5380 400 to 6000 MHz Quadrature Demodulator, 500MHz bandwidth.

- AD8366 DC to 600 MHz, Dual-Digital Variable Gain ( 4.5dB to 20.5dB) Amplifiers.

- AD9643 14-Bit, 250 MSPS, Dual Analog-to-Digital Converter (ADC).

- ADF4351 Wideband Synthesizer with Integrated VCO (35MHz to 4400MHz).

FPGA Interface

- adc_data_in[13:0] : 14 bit interleaved I/Q samples from ADC to the FPGA

- adc_clk_in : clock from ADC to FPGA in sync with the data

- adc_or_in : overrange at the ADC input is indicated by this bit (with some latency)

Receive Bandwidth

ADL5380 baseband response shows the 3dB point at 300MHz.

Reference Design