AMC-PICO-8

8-channel bipolar picoammeter AMC board in MTCA.4 format

The analog front-end is composed of a specially designed transimpedance input stage for current sensing combined with analog signal conditioning and filtering stages making use of state-of-the-art electronics. The 20-bit resolution is obtained from independent, simultaneous sampling and low-delay SAR (Successive Approximation Register) Analog to Digital Converters (ADCs).

Each channel has two full-scale measuring ranges and the current source can be floating up to ±300 V respect to the chassis ground. The floating capability of the inputs is perfectly suitable for applications where the detector or current source needs to be biased.

Different versions are commercially available:

• AMC-PICO-8: ±1 mA, ±1 uA, BW = 10 kHz;
• AMC-PICO-8-C1: ±130 uA, ±16 uA, BW = 35 kHz;
• AMC-PICO-8-C2: ±10 mA, ±500 uA, BW = 300 kHz;
• AMC-PICO-8-C3: ±1 mA, ±100 uA, BW = 30 kHz;
• AMC-PICO-8-C4: ±1 mA BW = 200 kHz, ±20 uA BW = 160 kHz

Custom solutions are available upon specific request.

Low noise, low temperature dependence and extremely small unbalance among channels

The pure analog characteristics are additionally improved with digital channel calibration. Calibration data are stored in the on-board EEPROM memory and are loaded in the signal-processing logic on power-up.

The on board Virtex-5 FPGA performs the conversion from raw data values acquired from ADCs to a single-precision floating point numbers, representing the measured current in amperes [A]. The floating point format is highly suitable for additional post-processing. The signal-processing logic can also be configured to capture the signal on certain trigger condition. Additionally, the internal memory can also be programmed to store data before trigger condition happens, providing a valuable data to user.

The communication with Virtex-5 FPGA is performed with the PCI express bus. All system parameters (e.g. analog front-end range, sampling frequency) can be achieved by writing to appropriate registers from PCI express. The FPGA also embeds a Scatter-Gather DMA which can be used to transfer data to PCI express root port (e.g. CPU).