A source measure unit (SMU), also called a source meter, is a test instrument that simultaneously measures and sources current and voltage. Source meters combine the functionality of a DC power supply, a multimeter, a current source, and an electronic load. Compared to traditional systems, in which all these features are achieved with separate pieces of test equipment, an SMU is far more efficient. Source measure units speed up test station development, setup, and maintenance times, simplify sophisticated connection and synchronization problems, and occupy a single space on the lab bench or rack rather than taking up multiple. Another advantage of a source measuring unit is that users can source voltage and current across positive and negative values by means of the SMU’s four-quadrant output. A typical SMU will offer 5.5 or 6.5 digits of resolution and allow users to select from a wide array of power envelopes. Engineers use an SMU for applications that call for high accuracy, high resolution, and flexibility of measurement, like IV characterization and semiconductor testing. With very high accuracy and resolution, a source measure unit can measure small signal voltages and current values in the millivolt (mV) and picoamp (pA) range. A source measure unit is typically a lab bench tool that can replace or complement the following tools:
- DC Power Supplies
- DC Loads
- Digital Multimeters
- Precision Power Analyzers
- Semiconductor Parameter Analyzer