Chroma ATE Inc.

PXI SMU/Power Supply Instrument
PXI SMU/Power Supply Instrument

High Precision Source Measure Unit (SMU) Model 52400e series

PXI Systems Alliance
Key Features:
  • 1- Slot PXI express module
  • 2/4 independent channels (4 ch for Model 52401e-6-1)
  • 18-bit resolution
  • Four quadrant operation
  • 6-wire Force/Sense/Guard
  • Low output noise
  • DIO/Trigger bits
  • Deterministic hardware sequencer
  • Programmable resistance
  • 16 control bandwidth selection
  • Master/Slave operation
  • LabView/LabWindows & C/C#
  • Softpanel GUI



  • Semiconductor
  • LED / Laser Diode
  • Solar Cell
  • Battery / BMS
  • Transistor
  • Automotive
  • Avionics
  • Power Electronics
  • Sensor / IoT

The Chroma 52400e series is a PXIe based SMU (Source Measurement Unit) card designed for highly accurate source or load simulation with precision voltage and current measurements.

The SMU combines four-quadrant operation with precision and high speed measurement. This makes the SMU an ideal instrument in many parametric test applications ranging from ICs, two-leaded components such as sensors, LEDs, laser diodes, transistors, to solar cells, batteries and many other electronic devices.

The 52400e series features: 16 selectable control bandwidths to ensure high speed output and stable operation; multiple source/measure ranges with an 18-bit DAC/ADC to provide the best resolution and accuracy available with a sampling rate up to 100K s/S; programmable internal series resistance for battery simulation; ±force, ±sense and ±guards lines to avoid leakage current and reduce settling time -- especially useful for low current test applications.

The 52400e series has a patented hardware sequence engine that uses deterministic timing to control each SMU. The sequencer's on-board memory can store up to 65535 sequencer commands and 32k measurement samples per channel, allowing cross module/ card synchronization and latency free output control and measurement. No PC communication is required during execution of the hardware sequencer test process.

C, C#, LabView, LabWindows APIs and versatile soft front panels come standard with each SMU. The back connectors are compatible with both PXIe and hybrid chassis. All of these features enable easy integration to PXIe or PXI-hybrid systems designed for a wide range of applications.


All Chroma 52400e series SMUs support four quadrant operation for applications that require a reverse voltage/current source or load. During a load operation, the module is limited by the PXI chassis' standard of 20W heat dissipation per slot. Shown below are the quadrant diagrams with the operating regions of the Chroma PXIe SMUs:



To reduce test times, Chroma's SMUs are designed for fast response providing high speed output voltage and current. The impedance of the DUT, fixture, or cabling may cause loop instability under voltage or current source mode. An unstable loop can cause saturation, oscillation, or even damage the DUT.

To prevent system instability, the 52400e series SMUs provide 16 user selectable control bandwidths, eliminating the need for external capacitors or inductors placed near the DUT. This results in faster output rise time, reduced voltage ripple and noise, and reduced transient response. The control bandwidth can be modified via software to maximize test flexibility and minimize downtime when changing DUTs.

SMU Output Waveform under Bandwidth Control


The Chroma Hardware Sequencer is a powerful tool that can predefine commands as instrument executable steps. This allows latency free control and measurement since no PC interaction is required during execution. The sequence optimizes the module's performance for applications like semiconductor test where speed and timing control are critical.

In this mode, once the instrument receives the start trigger, it will execute the commands in the sequencer table line by line or as defined upon trigger. Screen capture shown on the right is an example of a sequence profile setting by using Soft Front Panel provided by Chroma.





Guarding is an important technique for very-low current measurements. Guarding reduces Leakage Current error and decreases Settling Time. It keeps the potential of the guard connector at the same potential as the force conductor, so current does not flow between the force and guard conductors. It also eliminates the cable capacitance between source measure unit (SMU) and DUT for faster and more accurate measurements.


For maximum flexibility, Chroma 52400e series SMUs allow Master/Slave operation when higher current under FVMI mode is required. To ensure accurate current sharing between modules, and maximum performance, Chroma SMUs allow only similar models paralleled for higher current/ power.

Current sharing is achieved by one channel operating as the Master under FVMI mode while the Slaves operate in FIMV mode. The Master channel is programmed in voltage mode while the Slaves are set to current mode. The Slaves will follow the Master's set voltage.

Figure on the right displays a blocked diagram for parallel configuration.

Wiring Structure for Master/Slave Control