Simplified Access
Overcrowded Chips
Miniaturisation, power saving and cost saving are all driving higher levels of integration in electronics. For the microchip industry, this has meant putting more functional blocks on a single chip, creating complex System-on-Chip (SoC) devices. Even as the trend towards more complex SoCs continues, a new approach is emerging that puts more than one chip in a single package, called System-in-Package (SiP).
The density of SoCs has quadrupled every four years in line with Moore’s Law, but the number of connection “pads” available around the edge has changed very little.
The situation for SiP is worse still, as many of the available pads are used to connect between chips and so are not available to connect to the external pins on the package.
The Analog Test Access problem
Testing digital blocks within SoC or SiP devices is usually carried out with a single test bus (often a JTAG interface), so increasing integration does not lead to a need for more test pins.
Most SoC devices also contain mixed signal blocks for example, audio, video or sensors. The tests need analog and often some digital signals to be routed to external pins. While multiplexers can allow sharing of pads and pins, they also force tests to be run sequentially (instead of simultaneously) which slows down testing and increases costs even further.
For SIPs, it can be impossible to fully test all blocks after final assembly due to the limited number of pads and pins available, creating a substantial risk that defective parts will be shipped to customers.
LinBIST Solves Analog Test Access Problems
LinBIST integrates the test onto the chip alongside the block to be tested. This means there is no need for external connections to an analog tester, and the required digital connections can be shared with existing tests. The LinBIST IP block can be configured to share existing I2C, SPI or JTAG interfaces.
With LinBIST, analog and mixed signal blocks of complex designs can be tested...
- without the need for dedicated test pins
- in fully assembled SiP products
- in parallel with other tests