2 Smart Routing and Tiny IC Packages

A proper pinout assignment is critical to make sure a simple component placement and a small design size. It is also important to provide an easy access to all available pins on the package of the device. To integrate an I²C communication interface, two additional logic pins, SDA and SCL, need to be added. To allow easy routing without expensive microvias, the I²C pins should be added on the outside of the device.

The TPS62861 combines a flexible design and a small design size. The TPS62861 is housed in a 8-pin tiny 0.7x1.4mm wafer chip scale package (WCSP). Figure 3-2 shows the PCB layout of the TPS62861 which is optimized for the design size of 12 mm² and has all pins accessible from the outside of the package. No vias are required for connecting to the IC.

Figure 2-1 TPS62861 Layout Connecting all Pins Without Vias

Layout Matters: Solving Pinout Assignment Issues for DC/DC Converters in WCSP Packages is a technical article describing how a good pinout assignment can help for a small and simple implementation of a DC/DC converter with an I²C communication interface.