1000BASE-T/100BASE-TX/10BASE-T Physical Layer Compliance Tests Manual
Intel Confidential
15
1000BASE-T Maximum Output Droop
3
1000BASE-T Maximum Output Droop
IEEE Standard 40.6.1.2.2
3.1
Test Purpose
To ensure that the LAN analog front end (AFE) is capable of handling DC bias. This test uses “Test
Mode 1" as defined by the IEEE 802.3 Specification, section 40.6.1.1.2. An example of the test
mode 1 waveform is shown below.
3.2
Specification
•
Point G amplitude > 73.1% of point F amplitude; point G is exactly 500 ns after F.
•
Point J amplitude > 73.1% of point H amplitude; point J is exactly 500 ns after H.
•
The above is true for all four MDI channels.
If the LAN design does not meet the output droop requirement, the open circuit inductance (OCL)
for all four channels of the magnetics module should be verified and equal at least 350 µH with an
8 mA DC bias. (The OCL requirement is explained in more detail in the ANSI TP-PMD,
100BASE-TX physical layer specification.)
Figure 3-1. Example of Test Mode 1 Waveform
