Manufacturers of automatic test equipment (ATE) face two constant and opposing challenges. First, they have to make test and measurement systems that match the faster, higher-frequency circuits of new system-on-a-chip (SoC) ICs and leading-edge boards. Second, they have to do so while cutting test time and costs. The solution to both problems lies in better pin electronics.
Pin electronics interface the devices under test (DUTs) to the rest of the system. These circuits apply the test signals and acquire the test results. Great pin electronics separates the best ATE systems from the rest of the pack. For example, Semtech’s Cobalt platform offers lower power, a small footprint, high timing accuracy, small-swing capability, higher throughput, and cost savings.
Cobalt consists of the parametric measurement unit (PMU), which is programmable through the 16-bit digital-to-analog converters (DACs) on each input pin (see the figure). A 16-bit analog-to-digital converter (ADC) for each PMU connected to the IVMON eliminates the bottleneck that often occurs in some test systems where multiple pin channels must share a single ADC. The tri-level driver forces two levels (high and low) to the DUT as well as a third voltage for a termination level. It also can be configured to a high impedance state.
The diode bridge represents the active load with ranges of 4 and 40 mA. The driver, comparator, and PMU voltage levels feature an 8-V span over a –2- to +7-V range. Users program the unit by loading the digital-to-analog converter (DAC) and other registers with SET commands in the Semtech PinCast software. A 50-Mbyte/s serial peripheral interface sends programming data to the pin chip.
Settling time is less than 12 µs. The newest Cobalt ICs offer a small voltage swing capability with programmable levels of 25, 50, 100, and 250 mV. They can be configured as single-ended or differential. The programmer driver has variable fall times. All pin electronics circuit elements can be powered on of off individually via the serial interface to optimize system power dissipation, which ranges from 0.8 to 1.55 W per channel, depending upon the model. The super-thin (1 mm), 96-pin quad-flat no lead (QFN) package measures 11 by 11 mm with very low inductance to minimize parasitic loss. All models are pin-compatible.
The Cobalt line consists of six dual-channel devices with differential-mode capability and 16-bit programming DACs. Some models have the PMU with ADC, and some do not. Some models feature the active load, while others do not. The E8400, E8403, E8404, and E8405 are 500-MHz devices, while the E8410 and E8415 are 1-GHz devices. All are suitable for logic testers, mixed-signal test equipment, memory testers, flash testers, ASIC verifiers, and other ATE test heads. Available now, prices range from $46.66 to $64.66 in 1000-unit quantities.