Universal LVDS ribbon cable Marc Defossez 12 th
Universal LVDS ribbon cable Marc Defossez 12 th December 2005
Generic Schematic Symbol IO IO IO PCB mounted QSE part IO IO IO IO IO IO CLK / Sync / IO 2 CLK / Sync / IO QSE / QTE – 028 -01 -L-D-DP-A CLK / Sync / IO
Schematic Symbol This represents a ground connection. • These pins are physically not available on a differential pair QSE / QTE Samtec connector. • They are available when using the standard type QSE or QTE connectors. • Represented with the ground connections is the middle-connector ground plane. • 3
N P 15 N P 13 N P 11 N P 9 N P 7 N P 5 N P 3 N P 1 N P nc nc 4 Tranmitter PCB N P Syncside. N P 14 N P 12 N P 10 N P 8 N P 6 N P 4 N P 2 N P 0 nc nc Due to the symmetry of the cable, both connectors can not be placed the same way. The receiver side of the connector can be found on next page. PCB mounted QSE part CLK QSE / QTE – 028 -01 -L-D-DP-A- XLVDS Schematic Symbol
XLVDS Schematic Symbol Sync Receiver PCB N P 15 N P 14 13 N P 12 11 N P 10 9 N P 8 7 N P 6 5 N P 4 3 N P 2 1 N P 0 nc nc nc 5 nc nc nc side. Due to the symmetry of the cable, both connectors can not be placed the same way. The transmitter side of the connector can be found on previous page. PCB mounted QSE part N P QSE / QTE – 028 -01 -L-D-DP-A- CLK
XVam. Pire Schematic Symbol CLK N P Sync 25 N P 24 On the XVam. Pire Board there are 64 LVDS channels. This connector shows only part of them. 23 N P 22 21 N P 20 19 N P 18 17 N P 16 15 N P 14 13 N P 12 11 N P 10 9 N P 8 7 N P 6 5 N P 4 3 N P 2 1 N P 0 The differential IO are spread over two banks (2*TX and 2*RX). When taking two fully occupied connectors, a third one can be used to share the remaining signals or two not completely occupied connectors can be used only Clk, sync populated with the remaining 63: 38 pins of the bank. 37: 26 25: 0 Clk, sync 6 QSE / QTE 028 -01 -L-D-DP-A- Tranmitter PCB side.
XVam. Pire Schematic Symbol N P Sync 25 N P 24 23 N P 22 21 N P 20 19 N P 18 17 N P 16 15 N P 14 13 N P 12 11 N P 10 9 N P 8 7 N P 6 5 N P 4 3 N P N P 2 1 N P 0 7 QSE / QTE – 028 -01 -L-D-DP-A- CLK Receiver PCB side. On the XVam. Pire Board there are 64 LVDS channels. This connector shows only part of them. The differential IO are spread over two banks (2*TX and 2*RX). When taking two fully occupied connectors, a third one can be used to share the remaining signals or two not completely occupied connectors can be used only Clk, sync populated with the remaining 63: 39 pins of the bank. 37: 26 25: 0 Clk, sync
0. 80 8 0. 46 2. 87 2. 27 0. 43 1. 02 DIA 20. 00 16. 13 4. 70 2. 79 01 0. 19 Number of banks x 20. 00 + 0. 13 20. 00 6. 35 5. 74 Courtesy of SAMTEC 5. 02 0. 41 PCB Layout QSE-028 -xx part
PCB Layout QSE-040 -xx or QSE-028 -xx part If termination resistors need to be placed close to the connector, this can be the lay-out otherwise these pads can be used as test connection points for of Ground differential probes. the middle-connector ground shield. A ground shield has been placed on the PCB layer under the connector. The differential connector does not have the ground connections between the signal pins ! We decided to design them in to get optimal signal shielding (creation of a guard ring). 9 If termination resistor need to be placed clo to the connector, this can be the lay-out. Ground connection o the middle-connecto ground shield.
Connector details Single v Differential Two different style connectors are available from SAMTEC for the QSE/QTE series, that can share the same PCB layout, shown earlier. QSE-028 -01 -x-D-DP-A is a Differential Pair connector and QSE-040 -01 -x-D-A – a Single ended connector. The differential pair connector has a pin pair arrangement. surrounded by gaps/or unpopulated pins in the body. One out of three pins is missing. The single ended version of the connector can be seen as universal connector since all pins are populated. The connector can thus be used in single ended and differential pair applications. 10
Cable details Cables are available from Samtec. The order numbers - please see page on cable spec 50 Ohm Single ended EQCD-040 -11. 81 -TEU 100 Ohm Differential EQDP-028 -11. 81 -TEU-T The connectors are SAMTEC QSE and QTE. Specifications are available at: http: //www. samtec. com/suddenspecs/techspec. asp? series=QSE Technical specifications can be found at: http: //www. samtec. com/suddenspecs/techspec_test. asp? series=QSE 11
Cable Specification READ THIS! Customers should be aware that cables can be specified as wired straight through or twisted, additionally - connector mechanical polarization must be considered. In terms of Cable wiring connections, because a PCB is used to mount connectors at the cable ends there are 16 different combinations that a cable wiring can be specified. The Samtec web site provides circuit diagrams of Cables which can be used to confirm the suitability of any particular cable for an application. 12
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