The DDPCA-300 Variable Gain Sub Femto Current Amplifier is the latest wide-range low-noise transimpedance amplifier. Its specialized design enables input noise reduction to 0.2 fA/√Hz and a peak noise level of 0.4 fA. The variable gain range from 10^4 to 10^13 V/A can be adjusted either manually or via a remote interface. This amplifier covers a maximum current dynamic range exceeding 240 dB, enabling measurements from sub-femtoamperes to milliamperes with a simple switch. To avoid signal interference and noise caused by long cables, the housing must be placed as close as possible to the signal source. Integrated filters allow adjustment of the amplifier bandwidth to match varying signal conditions. As a result, the signal-to-noise ratio and measurement speed are sufficient for real-time femtoampere current measurements without the need for additional averaging or extended test cycles (refer to Table 1 below).

LOW DRIFT FOR STABLE LONG-TERM PERFORMANCE

Drift and offset currents in femto-ampere measurements can easily cause measurement errors and baseline shifts. The DDPCA-300 is designed for long-term stability and exceptionally low drift. The data below shows the amplifier's baseline stability remains below 0.5 fA over a measurement cycle of more than 7 hours. In unavoidable situations (e.g., temperature-related effects), an offset adjustment mechanism is used to cancel unwanted bias currents and zero the baseline. The device is characterized using the source reverse bias method.

This highly sensitive DDPCA-300 can be used in low-current applications such as high-resistance semiconductors (e.g., MOSFETs and JFETs) or quantum dot devices. An adjustable voltage can be applied directly at the amplifier input to bias the device under test (DUT). The adjustment range of ±10 V, controllable either manually or remotely, allows the DUT to be tested under various bias conditions in spectroscopic applications. This device is not suitable for applications requiring bias in photocurrent testing or beam current detection, as bias can easily fail in particle physics scenarios.

VARIABLE GAIN SUB FEMTO AMPERE CURRENT AMPLIFIER DDPCA-300

0.4 fA peak noise

Variable gain from 10^4 to 10^13 V/A

240 dB dynamic range from sub-fA to mA measurements

Adjustable input voltage for DUT biasing

Housing should be placed close to the signal source

Manual or remote control

*The bandwidth, rise time, and integrated input noise values listed in the table above are achieved with the low-pass filter set to full bandwidth. Lower peak noise can be achieved by setting the low-pass filter to 0.7 Hz or 0.1 Hz. The minimum peak noise of 0.4 fA is achieved at gains of 10^12 and 10^13 V/A with the low-pass filter set to 0.1 Hz.

Offset can be adjusted via a trim pot. Overload alarm is indicated via an LED and digital control output. The input is protected against transient voltages up to ±2 kV. The output is short-circuit protected. Power is supplied via a 3-pin Lemo connector. Matching connectors are provided with the device. The PS-15 can be used as a power supply. For more detailed information, please refer to the datasheet or contact us.