HCA Fast current amplifier series - Features

1. Bandwidth up to 400 MHz

2. The lowest input noise is 270 fA/√Hz

3. Gain up to 10 6V /A

4. Optimization models are provided for high source capacitances up to 2 nF

5. Adjustable bias of external photodiode

6. Compact size

Users of high-frequency components often face problems such as self-excitation (vibration), shielding/grounding issues, nonlinearity, and frequency response spikes. In many cases, technical product specifications lead to misunderstandings in the absence of necessary background knowledge. For example, instead of observing the expected flat frequency curve of up to 100 MHz after extensive wiring work, we can only observe a disappointing 30 MHz bandwidth and a strong amplification peak.

The FEMTO HF amplifier is designed in a way that does not present such problems. They are insensitive to the parameters of different signal sources and input wiring and perform well within their technical specifications without gain overshoot, self-excitation, or reduced bandwidth.

For some high-frequency current amplifiers, a source capacitance of only a few picofarads is sufficient to reduce the bandwidth substantially. In contrast, FEMTO current amplifiers have no such limitations and are not even affected by a wide range of source capacitances. Frequency compensation measures or special adjustments are redundant.

The models labeled "C" are optimized amplifiers that can handle even detector capacities as low as the nafarra range. They are particularly suitable for large-area detectors when fast signals in the low nanosecond range are to be measured. For detectors larger than 1 nF, we also offer special, customer-specific models. Please contact us!

To achieve high flexibility, FEMTO's HCA current amplifier provides accurate offset and bias control via two fine-tuned potentiometers. A wide range of adjustable input offset current compensation ensures a complete dynamic range, even for signals with large DC components. The voltage at the offset output can be accurately set to -12 to +12 volts using a multi-turn bias fine-tuning potentiometer. This is a simple and effective way to bias photodiodes, so they can achieve short rise times for fast measurements.

Note: The specified 3dB bandwidth of ±15% is maintained up to the maximum source capacity described above. Even larger capacity can be available, but the bandwidth and frequency response may be affected.