What is a precision source measure unit (SMU)?

A precision source measure unit (SMU) is a highly accurate electronic instrument that integrates the functionalities of a power supply, digital multimeter (DMM), electronic load, and current/voltage source into a single device. Unlike conventional power supplies, source measurement units operate in four quadrants, allowing them to source and sink both voltage and current with exceptional precision. This makes them ideal for characterizing electronic components, semiconductor devices, batteries, and materials that require highly stable and low-noise power delivery along with precise measurement capabilities. Source measure unit offer high-resolution sourcing and measuring capabilities, often down to femtoampere (fA) and nanovolt (nV) levels, making them essential for applications like IV curve tracing, leakage current testing, and power device characterization. Advanced models feature programmable sweeps, graphical displays, and automation interfaces for streamlined testing in research, production, and quality control environments. Their ability to provide highly accurate and stable measurements while dynamically adjusting voltage and current levels makes SMUs a critical tool for engineers and scientists working in semiconductors, nanotechnology, power electronics, and battery testing.

How does an SMU differ from a standard power supply or a multimeter?

A source measure unit (SMU) differs from a standard power supply and digital multimeter (DMM) by integrating both precise sourcing and measurement capabilities into a single instrument, allowing for highly controlled and accurate electrical testing. Unlike a standard power supply, which can only source voltage or current with limited precision and lacks high-accuracy measurement capabilities, a source measure unit operates in four quadrants. This means it can both source and sink voltage and current with precise control, enabling it to function as a power supply, an electronic load, or even a constant voltage/current source. Compared to a digital multimeter, which is designed solely for passive measurement and cannot supply power, a source measure unit provides active sourcing capabilities while simultaneously measuring voltage and current with exceptional accuracy, often reaching femtoampere (fA) and nanovolt (nV) levels. Additionally, source measure unit offer programmable sweeps, compliance (limit) settings, and advanced automation features. These capabilities make them ideal for applications such as IV curve characterization, semiconductor testing, and battery simulation—where both precise power control and highly sensitive measurements are critical.

What are the key advantages of using an SMU for testing?

The key advantages of using a source measure unit (SMU) include: Simultaneous sourcing & measuring : precisely sources and measures voltage and current at the same time, which enhances efficiency and versatility in testing. 4-quadrant operation: functions as a power supply, electronic load, and high-precision measurement device, and is capable of sourcing and sinking power for comprehensive testing. Tightly integrated sourcing & measuring: eliminates errors caused by using separate power supplies and multimeters, r educes setup complexity, and improves measurement accuracy. High resolution & sensitivity: measures down to femtoampere (fA) and nanovolt (nV) levels, which is essential for low-power semiconductor testing, leakage current measurements, and nanotechnology research. Programmable sweeps & automation: supports IV curve tracing, power device characterization, and battery simulation, which enables efficient, automated testing without additional equipment. Ideal for a wide range of applications: used in semiconductors, power electronics, materials research, and battery testing to ensure reliable, repeatable results in R&D and production environments.

What industries commonly use a source measure unit?

Source measure units are widely used across various industries that require high-precision electrical sourcing and measurement for testing, characterization, and validation of electronic components and systems. The semiconductor industry relies heavily on source measure units for IV curve characterization, leakage current testing, and breakdown voltage measurements of transistors, diodes, and MOSFETs. In power electronics, Source measure units are used to test IGBTs, GaN, and SiC power devices and evaluate the performance of DC-DC converters, power supplies, and battery management systems (BMS). The battery and energy storage industry uses SMUs for battery cell simulation, charge/discharge cycling, and fuel cell research. In LED and laser diode testing, a source measure unit enables precise current-voltage characterization and optical power analysis. The aerospace and automotive sectors depend on source measure units for electronic component reliability testing, sensor calibration, and electric vehicle (EV) battery simulations. In materials science and nanotechnology, SMUs facilitate the study of graphene, carbon nanotubes, and thin-film materials by enabling ultra-low current and voltage measurements.

Source Measure Units Precise and reliable testing, from basic integrated circuits to complex systems

Keysight offers three performance grades of SMUs — Essential, Expert, and Pro. Any of these can be built out based on features and performance you need.

Benchtop Source Measure Units

Precise voltage and current sourcing with simultaneous measurement capabilities
Modular Source Measurement Units

Compact form factor enables efficient multichannel configurations