The PWS SMU card has four highly accurate source/measure units (SMU), and two voltage-source/measure units (VS). Each SMU can force voltage while measuring current, or force current while measuring voltage. The VS’s can measure voltage and current while forcing a voltage. PWS can perform sweep measurement or discrete sampling measurement.
In addition to traditional DC force/measure, you can force an AC stress using PWS’s PULSE mode. In PULSE mode, user-selected SMU’s and VS’s are programmed to an initial value and then simultaneously pulsed to a different value for a programmed duration, with measurements taken at the end of the pulse. Pulsed measurements are useful when long exposure to certain bias conditions could cause parameter changes (e.g. due to heating).
The PWS also has a programmable SERVO feature wherein the current/voltage output of one SMU is driven based on the sensed current/voltage condition of a second SMU. A typical use of the SERVO feature is FET characterization where one SMU would be programmed to a DC voltage for DRAIN bias and a second SMU would drive the FET’s GATE voltage based on the sensed DRAIN current of the first SMU.
Guarded Switch Matrix Card
Switch Matrix cards consist of a 16 by 6 cross-point matrix of relay switches with each node separately switching a co-axial signal and its associated shield (guard). The matrix ties 16 external signals to an internal 6 wide buss connected to the SMU cards. The buss additionally provides for external connections to other instruments.