Credence Introduces PLLBOST Capability for Volume Testing of Mixed-Signal Devices.

FREMONT, Calif.--(BUSINESS WIRE)--Sept. 21, 1999--

Credence Systems Corporation (Nasdaq:CMOS), a leading manufacturer of automatic test equipment (ATE) for the worldwide semiconductor industry, today expanded its BOST (Built-Off Self-Test) technology offerings into the mixed signal testing arena with the introduction of PLLBOST (Phase Lock Loop BOST).

The PLLBOST capability leverages Fluence Technology's VCOBIST(TM) (Voltage Controlled Oscillator Built-in Self-Test) technology into Credence's suite of digital mixed-signal test platforms to provide engineers with a robust test coverage solution for volume production testing.

PLLBOST is a method for measuring frequency and jitter that is used to test PLL clock generation blocks on complex devices, such as graphics controller devices without specialized instrumentation. The test, or built-in self-test (BIST) circuit, is implemented into an field programmable gate array (FPGA) that is placed off the chip on the test fixture, hence BOST.

The test is based upon Fluence's VCOBIST technology to enable accurate, high-speed frequency and jitter measurements. This test methodology promotes test reuse. This key component of design reuse enables designers to wrap test-functions around design intellectual property (IP) blocks, thereby making the IP easier to reuse.

"Credence's advanced PLLBOST capability provides a means to reach the requisite quality levels for today's volume production cycles at the lowest possible cost of test," said Dennis Wolf, executive vice president and CFO of Credence.

PLLBOST utilizes a patent-pending algorithm developed by Fluence Technology's Opmaxx mixed signal design for test (DFT) group, to achieve fast, accurate jitter and frequency measurements with a small number of digital circuits. The test circuit is inserted into the device, in the case of BIST, or into the FPGA, in the case of BOST, in the form of synthesizable Verilog or VHDL that makes the frequency measurements.

To improve accuracy and to evaluate the jitter these measurements are fed to a patented histogram generator to create a histogram of the number of occurrences of each value of the frequency measurements. Both processes are extremely quick and efficient -- a 1,000-measurement-point histogram is created in less than 20 milliseconds, including calibration time.

"Credence is the world's first ATE manufacturer to incorporate Mixed-Signal BIST technology into its suite of digital mixed-signal test platforms. Mixed signal tests have escalated in cost and traditionally been hand crafted for each device, a time consuming and expensive process. The advent of mixed-signal DFT is changing this and BOST allows for an even quicker pace of acceptance and change," said John DiGirolamo CEO of Fluence Technology, Inc.

The decision to use BIST must be made very early in a design cycle. With BOST, however, a design team can begin to use BIST technology later in the design cycle and can demonstrate quality of test equivalent to traditional approaches.

The new mixed signal DFT methods are gaining acceptance for testing a variety of mixed signal functions such as digital to analog converters (DAC), analog to digital converters (ADC), amplifiers and filters. The BOST approach of testing these mixed-signal blocks using BIST techniques on the test fixture will allow users to achieve the cost savings of BIST techniques much sooner.

BIST and BOST are transforming the role of test from an expensive and passive device-validation procedure into a series of solutions that can shrink development cycles, reduce costs, meet time-to-market demands and improve die yields.

PLLBOST will be featured in Credence's booth (Booth No. 433) at the International Test Conference, being held September 28-30 at the Atlantic City Convention Center in Atlantic City, NJ.

About Fluence Technology Inc.

About Fluence Technology Fluence Technology, formerly known as TSSI, is a leading provider of mixed-signal design and test automation software technology and solutions. Fluence provides an integrated development environment between ASIC, EDA and ATE suppliers. More than 250 of the world's top electronics companies reduce time-to-market by using Fluence's innovative products, services and support.

Fluence has headquarters in Beaverton, Ore., with sales offices and distributors throughout the world. Please visit the company's web site at http://www.fluence.com or contact us at: [e-mail].

About Credence

Credence Systems Corporation is a leader in the manufacture of automatic test equipment (ATE) for the global semiconductor industry. Credence offers a wide range of products with test capabilities for digital, mixed-signal, and memory semiconductors. Utilizing its patented CMOS technologies, Credence products are designed to meet the strict time-to-market and cost of ownership requirements of its customers.

Headquartered in Fremont, the company maintains advanced production and design facilities in Hillsboro, Ore. Credence, an ISO 9001 certified manufacturer, is listed on the Nasdaq National Market under the symbol CMOS. More information is available at http://www.credence.com.

Note to Editors: Credence, Credence Systems and PLLBOST are trademarks of Credence Systems Corporation. Other trademarks that maybe mentioned in this release are the intellectual property of their respective owners.