A testing methodology for new-generation specialty memory devices

The authors describe the new requirements placed on tester hardware and software by new-generation specialty memory devices. Examples of real devices, including video RAMs, FIFOs, cache tags and SSRAMs (synchronous static RAMs), are used to illustrate the points. It is noted that specialty memories are creating complexities which demand new approaches in both hardware and software. Multiport devices, such as the TMS44C251 video RAM, are more easily tested on synchronized dual pattern generator test systems because the device program development process is eased and true independence of expect and drive data can be obtained. A method, implemented in hardware, by which data outputs can be delayed a few cycles from the presentation of address is required to test devices such as the MCM6294 SSRAM which contains latches on its inputs and outputs. IDT´s 72103 FIFO, with its complicated timing requirements and multiple setup modes, calls for an increased number of clocks and for timing, data, and formatting capabilities to be switchable at pattern speeds. Software tools also need enhancements to manage the complexities of specialty devices