Model 8010 High Power Device Test Fixture User's Manual
Section 3: Working with devices and instruments
8010-900-01 Rev. C / March 2017
3-17
DC measurements (leakage current)
The default state of the bias tee switch optimizes DC measurements.
AC and DC measurements (capacitance measurements)
Low Current (device in off-state):
Results in the most accurate AC and DC measurements possible
using the bias tee by adding isolation to the path of the DC instrument. The device should be in off-
state, as DC current is limited to very low levels.
High Current (device in on-state):
Results in moderate AC and DC measurement accuracy. This
state allows more DC current to pass through to the device under test. Test limits are 3 kV and 20 mA
with the 3 kV bias tee (model number 2650-RBT-3K), and 200 V and 20 mA with the 200 V bias tee
(model number 2600-RBT-200).
The bias tees' typical capacitance measurement are input (Ciss), output (Coss), and transfer
capacitance (Crss, Cres) measurements.
If you want to use the bias tees for AC and DC measurements, and then make DC only
measurements, in this case, you do not have to physically remove bias tees from your configuration.
This is possible since the bias tees can be programmed from AC + DC mode to DC only mode by
ACS Basic Software version 2.1 and newer. However, note that there are some limitations to the DC
only bias tee mode (see the
(on page 3-17)).
Bias tee theory overview
The CVU-3K-KIT and CVU-200-KIT bias tees combine C-V measurement with DC bias while isolating
the C-V instrument and SMU instrument from each other. A typical bias tee uses a capacitor to isolate
the C-V instrument from interfering with DC measurements and an inductor is used in series with the
SMU instrument to isolate the SMU from interfering with AC measurement (see next figure).
Figure 24: Typical coaxial bias tee block diagram
