SMU4000 measurement precision

6½ digit, 0.01µV & 100fA resolution

The SMU4001 has four voltage ranges from 20mV with 10nV resolution to 20V with 10µV resolution. The SMU4201 adds a 200V range with 100µV resolution. Voltage measurement burden is >10GΩ ±80pA. Both units have nine current ranges from 200nA with 100fA resolution to 3A with 1µA resolution. Basic accuracy is ±0.015% - see the specifications in the datasheet for details.

4 wire remote sense

In order to remove the effects of the resistance of the connection leads from low impedance measurements, sense terminals are provided, allowing precise regulation and measurement at the device under test and not just at the SMU terminals.

Driven Guard Terminals

When measuring from the rear terminals, a pair of guard outputs are available which provide a buffered output at the same potential as the force Hi terminal. This is for connection to shields which add protection from DC leakage currents in the sense circuits by surrounding them with a voltage identical that of the measurement node and are essential for making accurate measurements of small currents in high impedance applications.

High Reactance Mode

When attempting to source into reactive loads (capacitive and/or inductive), engaging the SMU4000 High Reactance Mode uses a lower bandwidth feedback loop with reduced compensation speed and increased settling time to provide more robust performance, reducing the chances of overshoot, ringing or instability.

Low noise

To accurately measure DC values in the presence of noise, the SMU4000 series measures at very high speeds internally and averages the results over user settable time periods. To minimize the effects of mains frequency interference, the averaging can be set to use integer multiples of the Power Line Cycle period (PLC). In this mode, the instrument internally measures the actual power line frequency and automatically synchronizes its averaging period.