FET: Ciss Test

Measures the device Input Capacitance. Requires the N1272A Device Capacitance Selector SMU.

Used with:

  • B1506A: FET DUT

  • B1505A: FET DUT, CV test type
Set the test parameters based on the specifications in the device's data sheet:
- If the data sheet lists a maximum test limit for a parameter, use that value.
- If there is no maximum test limit, use a typical value.

See also Setting IV and CV Test Parameters.

Test Schematic

Gate Parameters

VGS (V): The Gate bias voltage (V).

Frequency (Hz): The Measurement signal frequency (in Hz). NOTE: Keysight recommends that you use a 100 kHz measurement frequency when using the B1506A for this test (due to an additional error of its device capacitance switch).

Drain Parameters

VDSStart (V): The VDS sweep start voltage (V).

VDSStop (V): The VDS sweep stop voltage (V).

SweepOutput: Use the drop-down menu to choose the scale of sweep:

  • Linear - Linear sampling (see also the LinearNOS setting)

  • Log10 - 10 points/decade log sampling

  • Log25 - 25 points/decade log sampling

  • LOG50 - 50 points/decade log sampling

LinearNOS: The number of steps for LINEAR sweep scale (see the SweepOutput option).

Example

In this example, the discrete power FET is used as the example test device.

This device has the following basic characteristics.

  • VDSS: 2500V
  • ID: max 1.5 A (pulse)

General Settings:

  1. Choose FET as Device Type.
  2. Select the checkbox for either the Ciss, Coss, or Crss test.
  3. Set the measurement frequency to 1 MHz.

Base/Gate Voltage Bias:

  1. Set the gate voltage to 0 V to make the device turn off.

Collector/Drain Voltage Sweep:

  1. Set the sweep collector voltage from 0 V to 40 V.
  2. Select Linear as SweepOutput.