Window comparators for ATE apps deliver faster throughput

The new family of window comparators from Intersil Corp. enables semiconductor device testing with automatic test equipment (ATE) in large voltage swing applications without the need for bus isolation relays, saving set-up time and cost.

The testing of devices with large input or output voltage swing requirements, such as flash memory wafers that may use tester signals up to 15V, typically requires discrete isolation relays to disconnect test cards from the test bus when they are not in use. Intersil's new single-chip window comparators help save space by eliminating the need for isolation relays, and time by removing the set-up associated with the card isolation function, streamlining the testing process.

"Users can leave the ISL55141, ISL55142 and ISL55143 comparators connected to the bus while they are not being used, even when the bus is generating wide signal voltage levels from other test cards," said Chris Ludeman, marketing manager for Intersil's switch, multiplexer and ATE product group. "This allows for reduced tester set-up time, faster throughput and lower unit test costs for customers who buy these testers."

The new products utilize a window comparator architecture on-chip rather than the single comparator architectures of competing devices. This allows significantly more circuit integration on test cards, freeing up space for other tester functionality, explained Intersil.

In the window comparators, two reference voltages can be used to establish high and low specification points for a device output signal to be tested. In this way, it is possible to perform high-speed digital performance testing of semiconductor devices under a variety of load conditions.

These comparators provide a wide input voltage range and high input signal bandwidth to enhance test coverage, while the low input offset voltage enables very accurate signal testing. High input impedance across a wide input range can eliminate test bus isolation relays, resulting in lower product cost and more free board space.

In a typical application, the comparator is connected to a test bus. It receives static or dynamic signals from a device under test, then compares these signals to pre-defined reference voltage levels and provides digital output to indicate that the reference thresholds have been crossed. These outputs are then transmitted to the test controller at signal levels that can be set by the tester designer. This allows the tester to interface with a wide range of logic families.

All three devices include a power-down mode with less than 10?A of current draw. The ISL55141 includes a single window comparator, while the ISL55142 has two, and the ISL55143 provides four. All three versions can accept input signals up to 65MHz in frequency.

The ISL55141/2/3 family is available now in QFN and TSSOP packages. The ISL55141 is priced at $1.52, the ISL55142 at $2.02, and the ISL55143 at $3.91. All prices are in 1,000-unit quantities.