5.7 Buried layer layout (2s2p PCB only)The power and ground planes embedded in the board shall be of 35 m (1 oz.) copper +0/-20%. They are to be continuous except for via isolation clearance patterns. The power and ground planes shall terminate 1.0 mm from the edges of the PCB, giving overall plane dimensions as listed in table 3. The power and ground planes must not be present in the 9.5 mm edge connector pattern location shown in figure 2.Table 3 — PCB buried plane sizesPCB Size (+/- 0.25 mm) Buried Plane Size101.5 mm x 114.5 mm 99.5 mm x 99.5 mm127.0 mm x 139.5 mm 125.0 mm x 125.0 mm152.5 mm x 165.0 mm 150.5 mm x 150.5 mm5.8 PCB metalization characteristics for 1s and 2s2p PCBsFor packages with ball pitch > 0.5 mm, the top and bottom trace metalization on the PCB shall be 70 m (2 oz) +/- 20% finished thickness after final processing. For packages with ball pitch 0.5 mm, the top and bottom trace metalization on the PCB shall be 50 m (1.5 oz) +/- 20% finished thickness after final processing. This is achieved by starting with a 1 oz copper material and plating up to the target thickness during PCB through hole plating process. This process specification should be printed on all drawings to ensure proper processing. The thickness of the copper traces shall be verified to +/- 20% after PCB fabrication because thickness variations greater than this can have an excessive influence on the performance of the PCB. JEDEC Standard No. 51-9Page 115 Trace design (cont’d)5.9 Solder masks for 1s and 2s2p PCBsSolder masking is not optional and must follow the constraints described for the ball lands in 5.3.5.10 Plated through-hole vias for 1s and 2s2p PCBsThe plated through-hole vias at the border of the trace fan-out area and beyond shall have a solder land of no less than 1.25 mm diameter with a drill hole of no less than 0.85 mm diameter. A block out area or isolation clearance of diameter no greater than 0.70 mm larger than the drill hole diameter shall exist in the buried solid planes around each plated through-hole via. Other than this isolation clearance area, the buried planes are to be unbroken. Some buried plane copper must exist between via isolation clearance regions; the clearance regions are not to merge into one another.6 Hand wiring Connection to edge connector: Connection from the through-holes to the edge connector shall be made with 22AWG copper wire or smaller if the connections are not designed as part of the trace pattern.When the board is intended for use in forced air measurement environments, interconnect wiring to the edge connector shall be on the trailing edge of the board with respect to air flow direction and back side of the board with respect to the component placement. Interconnect wiring shall be outside the fan-out area. Figure 8 shows a suggestion for wiring from the leading edge of the test board to the trailing edge before being routed to the edge connector. Connection from the edge connector to the fan-out perimeter and from the fan-out perimeter to the power dissipation structures must be made in a four-point method for force (power) and sense (measure) purposes. Wire diameters for heating force currents may need to be larger to accommodate high power tests and may require more than one edge connector pin. Use table 4 as a guide to determine the required wire diameter [5,6].Table 4 — Wire size current limitsAWG Wire Size UL Current Capacity, (80 ºC), Amperes MIL-W-5088BAmperes30 0.4 N/A28 0.6 N/A26 1.0 N/A24 1.6 N/A22 2.5 5.020 4.0 8.318 6.0 15.416 10.0 19.414 16.0 31.212 26.0 40.0 JEDEC Standard No. 51-9 Page 126 Hand wiring (cont’d)Air Flow DirectionFigure 8 — Dashed lines show hand wiring across back of test board to avoid interupting air flow on leading edge of board for air flow measurement environments. JEDEC Standard No. 51-9Page 137 Data presentation Table 5 lists parameters specified by this document. The “user” column allows the user to input actual measured values from the test boards.