Dimtel LLRF4.6 Manual

Procurar online ou descarregar pdf Manual para Placa-mãe Dimtel LLRF4.6. Dimtel LLRF4.6 20 páginas.

Introduction

This document is an update of LLRF4 documentation packet, describing up-to-date in-

formation on 2013 LLRF4.6 revision of the board. The main diﬀerence between LLRF4

(last revision 4.2, dated 2009-06-28) and LLRF4.6 is the FPGA. The updated board uses

Spartan-6 FPGA in CS324 package. Normally, the boards are assembled with the largest

and fastest part ﬁtting the footprint — XC6SLX45-3CSG324. While smaller parts can be

used, there is little rationale to do so.

Besides the component changes, several new or improved features have been incorporated:

• Transition from Spartan-3 XC3S1000 to Spartan-6 XC6SLX45;

• New FPGA core supply switcher capable of 2.5 A;

• Power supply jumpers replaced by zero ohm resistors;

• Maximally ﬂat PCB backside for thermal pad mounting on cold plate;

• Reduced parasitics on RF/IF inputs

• High quality stripline LO distribution network, capable of 3 GHz;

• LO 1:8 splitter works to 3.4 GHz;

• LVDS signals routed as 100 Ω diﬀerential lines;

• LVDS termination resistors deleted;

• DS1822 thermometer in TO-92 replaced by DS18B20 in SO-8;

• Improved input channel shielding assembly.

The rest of this paper walks through these changes in detail.

FPGA

LLRF4.6 transitions to a more modern Xilinx FPGA. The part is also slightly faster

than the old Spartan-3. A short summary of diﬀerences between the two parts is shown

below. Of course, logic cells comparison is imprecise, since Spartan-6 uses new 6-input

LUT architecture. Xilinx uses some fudge factors to convert slice counts to vague "logic

cells".

Logic cells

Multipliers

BlockRAM

One quirk of LLRF4.6 FPGA setup is that two data bits on high-speed DAC interface are

driven by dual function pins R15 (IO L1P CCLK 2) and V10 (IO L30N GCLK0 USERCCLK 2).

The bitﬁle must be generated with startup clock set to CCLK (-g StartUpClk:CClk

option of bitgen) for these pins to function as user outputs.

LLRF4.6 Evaluation Board

Dmitry Teytelman

July 7, 2014

XC3S1000

XC6SLX45

17280

Notes

43661

DSP48A1 in S6

116

18kbits