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SMU goes high power

Martin Rowe- April 4, 2011

Keithley Instruments has introduced its fourth-generation SMU (source-measure unit), the Model 2651A SourceMeter. Designed for testing high-brightness LEDs, power MOSFETs, and other power devices, the 2651A can produce 200 W continuous power or 2000 W pulsed power. Continuous power ranges from ±40 V at ±5 A to ±10V at ±20 A. In pulsed mode, the 2651A can produce at ±50-A current pulse at up to ±40 V. If you need more power, you can operate two SMUs in series for up to 80 V or in parallel for 100 A.

The 2651A can produce stimulus pulses with as short at 100 µs. Programmable pulse-timing resolution is 1 µs. The programmable duty cycle ranges from 1% to 100%, which is DC.

On the its measurement side, the Model 2651A incorporates four ADCs, two for measuring voltage and two for measuring current. You can select an 18-bit ADC pair for high-speed (1 Msample/s) voltage and current measurements, or you can use the 22-bit integrating ADC pair when you need better accuracy and resolution. In the 20-V range the 18-bit ADCs' accuracy is 0.015% of reading +8 mV. The integrating ADCs reduce the additional 8 mV to 3 mV. Display resolution for measurements is 1 pA and 1 µV. The high-speed ADCs let you capture transients in voltage and current as the instrument applies stimulus  to your device under test. For example, you can set the ADC to measure a DUT's response just before or just after you apply a rising or falling voltage or current. That lets you see the DUT's condition immediately before applying a pulse. Then, you can switch to the integrating ADCs for DC and steady-state measurements.

The Model 2651A comes with LAN, GPIB, and USB ports for remote control. If you use LAN, you can download Keithley's TPS Express software right from the Model 2651A. The software lets you configure and operate one or two instruments either independently or combined. Software support also includes LabView drivers and a scripting tool for building your own automated tests.

Price: $13,700. Keithley Instruments, www.keithley.com.