SCDA044 January   2023 TMUX1308

 

  1.   Abstract
  2.   Trademarks
  3. 1Simplifying the Sourcing Strategy
    1. 1.1 Cost Savings and Increased Flexibility
    2. 1.2 Placement and Routing Tips
    3. 1.3 Example Secondary Footprints
    4. 1.4 Using Multiple Devices to Create Desired Multiplexer Configuration
  4. 2Summary
  5. 3References

1.3 Example Secondary Footprints

Common industry standard packages that can utilize secondary footprints are SOIC, TSSOPs, and VSSOPs. Examples are shown below.

The much smaller USON package easily fits within the VSSOP footprint. The pinout for each package match in this configuration.

GUID-BE9129CB-CA9D-4B48-9159-453F2728D08D-low.png Figure 1-1 VSSOP (DGS) – USON (DQA)

The WSON footprint is a tighter fit within the VSSOP footprint but it still has the required 4 mils of clearance between adjacent pins. The pinout for each package match in this configuration.

GUID-C30B7CA6-F971-42FE-97A4-BEB5D60A647F-low.png Figure 1-2 VSSOP (DGK) – WSON (RQX)

This example shows that with creativity, three footprints can be layered within the same space. The pinouts are the same for all three packages.

GUID-7A06F8DB-09D0-4F7B-AE60-416962B3FB74-low.png Figure 1-3 TSSOP (PW)-SOT-23-Thin (DYY)-WQFN (BQB)

The routing is more involved but the small size of the UQFN allows for the required spacing within the TSSOP footprint. The pinout for each package match in this configuration.

GUID-4D30900B-75EE-45E9-B4D0-10A96B199DAB-low.png Figure 1-4 TSSOP (PW)-UQFN (RSV)

Differences in pinout between the packages shown in this configuration. The TMUX6208 was used as the example device.

GUID-8E77EBE0-0608-4B0F-B871-82E530F1AC3E-low.png Figure 1-5 TSSOP (PW) - WQFN (RUM)