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Application Report
SNOA522A–May 2008–Revised April 2013
AN-1821 CPRI Repeater System
.....................................................................................................................................................
ABSTRACT
This application report implements the Common Public Radio Interface (CPRI) for Remote Radio Heads
(RRHs). The designer can use this application report for developing CPRI-based repeater systems in
point-to-point or multi-hop configurations. This application report consists of:
• Designs for the CPRI SerDes Repeater Boards for the Radio Equipment (RE) and Radio Equipment
Controller (REC) that include CPRI SerDes (SCAN25100) and a clock conditioner (LMK02000 or
LMK03000 family).
• CPRI framer sample code to enable up to four CPRI links. The designer can easily port this IP to
popular FPGAs.
Contents
1 System Design Overview .................................................................................................. 3
2 CPRI SerDes Repeater Boards (RE and REC) with SCAN25100 SerDes and LMK Clock Conditioners ...... 4
2.1 CPRI SerDes REC Board ......................................................................................... 4
2.2 CPRI SerDes RE Board ........................................................................................... 5
2.3 Hardware .......................................................................................................... 10
3 CPRI Framer/Deframer FPGA IP ........................................................................................ 13
4 Notes ........................................................................................................................ 14
5 Schematics and Bill Of Materials ........................................................................................ 14
5.1 REC Bill of Materials ............................................................................................. 14
5.2 RE Bill of Materials ............................................................................................... 16
5.3 REC Schematics .................................................................................................. 18
5.4 RE Schematics ................................................................................................... 24
List of Figures
1 Multi-Hop Configuration Example......................................................................................... 3
2 REC Board................................................................................................................... 5
3 Pre-LOCK Sequence ....................................................................................................... 7
4 Post-LOCK Sequence...................................................................................................... 7
5 Normal Operating Conditions.............................................................................................. 8
6 RE Board..................................................................................................................... 9
7 LMK02000 Phase Noise Plot ............................................................................................ 10
8 LMK03001D Phase Noise Plot .......................................................................................... 10
9 DS10CP154 I/O............................................................................................................ 11
10 External Clock Source/On-board Oscillator Mux Layout ............................................................. 12
11 Point-to-Point Configuration (shown with 2 CPRI links between nodes)........................................... 13
12 Loop-Through Setup (shown with 1 CPRI link between nodes)..................................................... 13
13 REC Schematic, Page 1.................................................................................................. 18
14 REC Schematic, Page 2.................................................................................................. 19
15 REC Schematic, Page 3.................................................................................................. 20
16 REC Schematic, Page 4.................................................................................................. 21
17 REC Schematic, Page 5.................................................................................................. 22
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SNOA522A–May 2008–Revised April 2013 AN-1821 CPRI Repeater System
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