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SLAA709–October 2016
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Copyright © 2016, Texas Instruments Incorporated
ARF Sampling DAC with 800 MHz of IBW LTE
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Application Report
SLAA709–October 2016
RF Sampling DAC with 800 MHz of IBW LTE
Kyung-wan Nam and ByungJun Goo ...................................................................... Wireless Infrastructure
ABSTRACT
This document describes a candidate device, DAC38RF8x, for the next generation (5G) cellular systems
that shows a total of 800 MHz of Instantaneous Bandwidth (IBW) using Long Term Evolution (LTE)
patterns (40 of LTE 20 MHz) captured from spectrum analyzer.
Over the last decade, the wireless infrastructure industry has been investing large amounts of research
and equipment in 3.5G (Mobile WiMAX), 3.9G (LTE), 4G (Advanced LTE) networks to provide higher data
rates to end users by deploying advanced technologies such as multiple-input-multiple-output (MIMO) and
carrier-aggregation (CA). 5G requires microwave and mmWave frequency bands (licensed and
unlicensed) with wide bandwidth up to 2 GHz or wider. The standard body of 5G specifications such as
the Third Generation Partnership Project (3GPP) envisions 28 GHz up to 40 GHz or higher of channel
frequency with 1 GHz of instantaneous bandwidth (IBW).
DAC38RF8x is a dual-channel 14-bit digital to analog converter (DAC) and provides 9 Gsps of DAC
sample rate. This device has an 8-lane JESD204B interface with a maximum input bit rate of 12.5 Gbps.
DAC38RF8x supports subclass 1 for multi-chip synchronization. Up to x24 of interpolation enables users
to transmit 375 MHz of baseband rate from FPGA, and 4 independent Numerically Controlled Oscillator
(NCO) supports 4 different frequency bands from one DAC38RF8x device.
Contents
1 Theory of Operation ......................................................................................................... 2
1.1 Test Pattern Profile of 800 MHz .................................................................................. 2
1.2 Operation of DAC38RF8x ......................................................................................... 4
2 Performance Evaluated from DAC38RF8xEVM ......................................................................... 6
3 Conclusion .................................................................................................................. 10
List of Figures
1 200 MHz of IBW Without Gain Equalization From MATLAB........................................................... 2
2 200 MHz of IBW With Gain Equalization From MATLAB .............................................................. 3
3 9.74 dB of PAR at 0.01% from CCDF Curve ............................................................................ 3
4 Baseband Complex I/Q Patterns in the Time Domain From MATLAB ............................................... 4
5 Block Diagram of Combined 800 MHz With Different NCOs .......................................................... 4
6 ACLR of 800 MHz IBW Measured (–55.55 dBc) From Spectrum Analyzer ......................................... 6
7 Measured EVM (0.45%) at 1.4532 GHz.................................................................................. 7
8 Measured EVM (0.47%) at 1.6532 GHz.................................................................................. 8
9 Measured EVM (0.49%) at 1.8732 GHz.................................................................................. 9
10 Measured EVM (0.52%) at 2.2332 GHz................................................................................. 10
List of Tables
1 Example of DAC38RF8x Configuration Parameters.................................................................... 5
2 JESD204B Frame Format for LMF = 882 ................................................................................ 5
