IEEE 370-2020 pdf free download – IEEE Standard for Electrical Characterization of Printed Circuit Board and Related Interconnects at Frequencies up to 50 GHz.
3.2.2.4 MIxed-mode S-parameter labeling
When characterizing ditfrrential interconnects, the measured single-ended S-parameters are ofien converted to inixed-nsude S-pansnsetems. using the equations in Annex C. Characteristics of ditTerential interconnects may he described using mixed-mode ports composed of pairs of single-ended port’- as follows:
Mixed-mode port I. which ts composed of single-ended ports I and 3 (see Figure I) Mixed-mode port 2, which is composed of single-ended port’. 2 and 4
The name of the S-parameter indwates the eonfigunttion: Sptszp (or 5010’) is the S-parameter associated with the signal ineasutvd at tnixed-nxsde ütt 2 due to a stimulus at mixed-mode poll I. The teturn loss of differential port I would he contained in S-parameter Sonti (or Snim). Likewise. Srcii is the S-parameter associated with the signal measured at differential port 2 due to a common stimulus at port I. If the alternate port numhenng ‘eheme of Figure 2 is usert, mixed-mode port I would he composed of single. ended porta I and 2, *lule rnixeitl-mode port 2 would be composed of single-ended ports 3 and 4
323 Labeling fixtures with two or four ports
12.31 Introduction
In this document the fixture name’. are based on the index number of the OUT port to which they attach.
12.3,2 Labeling and Idenlifying the fixture names
This standard recommends a specific labcling nictlsisl list each tisturc connected to the OUT. referred to as FIX-I. FIX-2. etc., and the port indices attached to each FIX. This is only a teconusteadation, as theme are alternative approaches in wide use that are also correct. There is iso industry-accepted method, and the user must serify in each application how the tixtute is connected to the OUT and the port indices.
A OUT may hase more than one fixture attached to it. On every 0111 port that has a tixture to dc-embed. the fixture is labeled based on the OUT port index number to wttich it connects
lit the cate of a two-port OUT, for example. the fixture attached to the single-ended OUT port I is labeled as FIX-I. The fixture attached to the single-ended OUT port 2 is labeled as FIX-2.
In the ease of differential ports with ditTerenttal fixtures. FIX-fl I is connected to the differential OUT port Dl. and FIX-D2 is cotusectcd to the difkrential OUT port 02.
323.3 Labeling and Identifying the ports of the fixture
This standard recommends labeling the fixture’s higher number port index as the one attached to the OUT and the lower number port index connected to the outside.
For example, in a 2X-Thru, composite structure. FIX-I port 2 is connected to 1)111 port I and FIX-2 port 2 is connected to OUT port 2.
On each fixture, port 2 of the fixture is connected to the OUT and pon I of each fixture is connected to the outside. These labels are illustrated in Figure 3.
It is very’ important thai the port labeling of the lixture assigned by the dc-embedding tool is checked to verify that it is consistent with expectations. Not all tools may autotnatically Label fixture potts the sante way
3.2.3.4 Naming of the fixture.DUT4Ixture
The nanse of the fixture may be shortened to FIX. For example, the composite slructtre could be referred to as the FIX-IKJi-FIX structure
The combination of the PITT and fixtures on either end is rekrtrd to as the compostte structure or the FIX- PUT-FIX structure. The combination of just the two fixtures, such as a FIX-I connected to a FIX-2. is refined to as a FIX-FIX structure or a 2X.Thru,
In the case of a xtngle port OUT, the composite structure ix rekrred to as a FIX-PITT, This labeling scheme tcmoves some of the ambiguity of the specific structure. In this standard, a FIX-OUT structure is described, hat not recommended,
3.2.3.5 Labeling fixtures for DUTs with multiple ports
When a fixture connects to the PUT with more than one port, the tiame of the fixture should contain the multiple 1)1ST ports connected, separated by underscores For example, the specific differential tixture connected to ports I and 3 of the DITT should be labeled as FIX-I_3. The fixture connected to the other end of thc OUT should be labeled as FIX-2 4.
If the differential port scheme were used to identify the PUT, the two fixture’. should he identified as FIX-DI and FIX-P2.
A fixture connected to two differential OUT ports slsould itself base four poets. These should he labeled
with port I as an outside port on one fixture and port I as an outside port on the other fixture, In a
differential fixture, the same consention is recommended, in which poet I is connected to port 2 and port 3
ix connected to port 4.
Wtth this recommendation, the differential fixture ports should be labeled:
FIX-Dl_l. FIX-Dl_2, FIX 013 and FIX-Ol_4
If a differential port labeling were used for the fixture, the ports should he labeled.IEEE 370 pdf download.