1-11
ASU
• 100 aA level sensing
• Channel switching
• C measurements
• PG for charge pumping
HRSMU Force
HRSMU control
C meter Hcur
ASU2
ASU1
HRSMU Force
HRSMU control
C meter Hpot
C meter Lcur
C meter Lpot
Hcur/Hpot or Force
Lcur/Lpot or
Force
Source
Source
Return path for C meter
The high-resolution SMU (HRSMU) has an innate 1 fA & 0.5 mV measurement resolution. The
optional ASU extends the HRSMU measurement resolution to 0.1 fA.
The ASU has another feature, built-in switching capability. It can switch between the SMU and an
auxiliary input (AUX input, two BNC).
If the Agilent 4284A LCR meter is connected to the AUX inputs, the ASU can switch between the
low current and CV measurements. Then connect a wire between the CMU return terminals of
ASUs to make the return path of measurement current. This is effective for accurate capacitance
measurement. However, you need to perform capacitance compensation by yourself.