National Semiconductor DS25CP104 User manual - page 10

DS25CP104EVK User Manual 

Equalization Performance Testing 

In some applications, data transmits over cables or long backplanes. The equalization 

function on the DS25CP104 receivers helps to compensate for loss of certain media; 

hence the DS25CP104EVK has three lengths of stripline to test the equalization function. 

1.

Configure the test setup as shown in Figure 6; select the desired test channel, 

lengths in Table 7. 

2.

Set the desired INn to OUTn drivers by selecting S00, S01, S10, S11, S20, S21, 

S30, S31 according to Tables 1 – 4.  

3.

Select the PEn jumpers to 0 and the EQn jumpers to 1, according to Tables 5 and 

6. 

4.

Apply + supply (3.3V typical) to the VDD and – supply (ground) to the VSS 

connectors.  

5.

Connect a signal source (signal generator, data source, or an LVDS driver) to the 

desired INn inputs on the board and adjust the signal parameters (VOH, VOL, 

VCM) so that they comply with the device input recommendations. 

6.

Connect an oscilloscope to the selected OUTn outputs and view the output 

signals with an oscilloscope with a bandwidth of at least 5 GHz. 

Figure 6

. Equalization Performance Test Circuit 

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