LinBIST FAQs
Is LinBIST suitable for embedded ADCs?
Yes, LinBIST is ideally suited to testing embedded ADCs, especially in SoCs.
What tester capabilities are needed for LinBIST?
LinBIST needs only a digital tester. Either a pass/fail signal or a serial interface is used to communicate with the tester.
What ADC architectures does LinBIST work with?
LinBIST tests are not in any way dependent on the architecture of the ADC, so LinBIST can work with any ADC architecture.
How long do LinBIST tests take to run?
Since LinBIST runs in the less noisy on-chip environment, it is faster than conventional test. The ADC resolution, sample rate, tests selected, test specification and level of noise will affect test times.
Is LinBIST as good as my current tests?
Yes, LinBIST is better than standard external test techniques.
Don’t test circuits need at least 2 bits better performance than the convertor under test?
Yes, LinBIST uses standard CMOS components and a patented algorithm and architecture to give an effective performance in excess of the convertor under test. LinBIST does not require any special or high tolerance on-chip components or external calibration.
What other on-chip components are needed for LinBIST?
The LinBIST IP needs very little in the way of on-chip support. The block requires power, a voltage reference, a clock, the ADC data output signals, and means of providing an input to the ADC (usually via a multiplexer). These resources are already available on most SoC devices, and are needed for other test approaches too.
How does noise affect LinBIST?
LinBIST benefits from the fact that there is typically less noise on-chip than on external connections to a tester. In any case, LinBIST’s algorithms are extremely robust even in the presence of substantial noise.
What parameters can LinBIST Test, and what specification of convertors?
Please see the LinBIST datasheet for details.
Can LinBIST test dynamic parameters such as THD and SINAD?
The current version of LinBIST tests static ADC parameters with limited dynamic testing. Full dynamic tests will be available shortly. Please contact ATEEDA for more information.
How does the pass/fail signal come out to the tester?
The LinBIST IP can provides a pass / fail through a signal pin and or a serial interface (I2C/SPI/JTAG)
What interfaces are supported for complex testing and device characterisation?
The LinBIST IP supports I2C, SPI or JTAG for communications.
Does LinBIST support characterisation as well as test?
ATEEDA can supply characterisation software which communicates with the LinBIST IP to provide characterisation of the parameters under test.
Does LinBIST need input signals, such as a high quality ramp or sine waves, from the tester?
The analog portion of the LinBIST IP generates all the signals needed for testing, so no signals are required from the tester. LinBIST tests can be run on digital testers.
Does LinBIST need a lot of memory, for example to store a histogram or calculate FFTs?
No, LinBIST needs only a small memory on-chip, the size of which depends on the resolution of the ADC and the test limits. The memory can be shared with other functions in most cases.
Does LinBIST require additional components on the load board, such as resistors or capacitors?
No, the LinBIST IP is fully integrated on the chip with patented techniques to minimise its size.
Can I simulate LinBIST tests?
Customers can efficiently simulate the full LinBIST IP with a mixed-signal simulator. ATEEDA can also supply a variety of analog and digital models to enable fast system-level simulations, including ADC models with parameterisable faults.
Can I verify the tests and IP along with the rest of my design?
Yes, the built in self test can be fully verified at design time along with the rest of the design.
Does LinBIST affect my yield?
Yes, LinBIST improves final test yield by catching faulty devices at wafer probe. The LinBIST IP is very small and no special tolerances are required so it does not negatively impact the SoC yield.
What happens if the LinBIST circuit isn’t working – do we have to test it too?
The LinBIST IP is small and unlikely to fail, but in the event of a manufacturing defect a fail is reported by the test. LinBIST’s digital IP is synthesized with the customer’s digital design, and can be included in the scan chain.