Texas Instruments FPD- Link LVDS to FPD-Link II Embedded Clock LVDS Converter DS99R421 Evaluation Kit FPDXSDUR-43USB/NOP FPDXSDUR-43USB/NOPB Datenbogen

 

 

National Semiconductor Corporation 

 

Date: 5/12/2008 
Page 23 of 39 

 

 
If the demo boards are not performing properly, use the following as a guide for quick 
solutions to potential problems.  If the problem persists, please contact the local Sales 
Representative for assistance. 
 
QUICK CHECKS: 
1.  Check that Power and Ground are connected to both Tx AND Rx boards. 
2.  Check the supply voltage (typical 3.3V) and also current draw with both Tx and Rx 

boards.  The Serializer board should draw about 55-65mA with clock and all data 
bits switching at 43MHz, (R

PRE

=9K

Ω).  The De-serializer board should draw about 

75-85mA with clock and all data bits switching at 43MHz, (minimum ROUT loading). 

3.  Verify input clock and input data signals meet requirements for VILmin, VILmax, 

VIHmin, VIHmax, tset, thold), also verify that data is strobed on the selected 
rising/falling (RFB pin) edge of the clock. 

4.  Check that the Jumpers and Switches are set correctly. 
5.  Check that the cable is properly connected. 
 
TROUBLESHOOTING CHART 
Problem… 

  Solution… 

There is only the output clock.  
There is no output data. 

 
 

 

 

Make sure the data is applied to the correct input pin. 
 
Make sure data is valid at the input. 

No output data and clock. 

  Make sure Power is on.  Input data and clock are 

active and connected correctly. 
 

 

  Make sure that the cable is secured to both demo 

boards. 

Power, ground, input data and 
input clock are connected 
correctly, but no outputs. 

  Check the Power Down pins of both Translator and 

De-serializer boards to make sure that the devices 
are enabled (/PD=Vcc) for operation.  Also check 
DEN on the Serializer board and REN on the 
Deserializer board is set HIGH. 

The devices are pulling more 
than 1A of current. 

  Check for shorts in the cables connecting the 

Translator and RX boards. 

After powering up the demo 
boards, the power supply 
reads less than 3V when it is 
set to 3.3V. 

  Use a larger power supply that will provide enough 

current for the demo boards, a 500mA minimum 
power supply is recommended.