Features
- Input noise down to 180 aA/√Hz
- Bandwidth up to 400 kHz
- Transimpedance amplifier with gain up to 1013 V/A
- Flat frequency response
- EMI-shielded case
| Model | -3dB Bandwidth (DC...) | Noise Current | Transimpedance (Gain) | Rise/Fall Time | Datasheet |
|---|---|---|---|---|---|
| LCA-2-10T | 2 Hz | 0.18 fA/√Hz | 1012 and 1013 V/A | 200 ms |  |
| LCA-30-1T | 30 Hz | 0.5 fA/√Hz | 1 x 1012 V/A | 12 ms | |
| LCA-30-200G | 30 Hz | 0.5 fA/√Hz | 2 x 1011 V/A | 12 ms | |
| LCA-200-100G | 200 Hz | 1.5 fA/√Hz | 1 x 1011 V/A | 2 ms | |
| LCA-200-10G | 200 Hz | 1.5 fA/√Hz | 1 x 1010 V/A | 2 ms | |
| LCA-1K-5G | 1 kHz | 3 fA/√Hz | 5 x 109 V/A | 400 µs | |
| LCA-2K-2G | 2 kHz | 4.5 fA/√Hz | 2 x 109 V/A | 200 µs | |
| LCA-4K-1G | 4 kHz | 6.5 fA/√Hz | 1 x 109 V/A | 100 µs | |
| LCA-10K-500M | 10 kHz | 10 fA/√Hz | 5 x 108 V/A | 40 µs | |
| LCA-20K-200M | 20 kHz | 14 fA/√Hz | 2 x 108 V/A | 20 µs | |
| LCA-40K-100M | 40 kHz | 19 fA/√Hz | 1 x 108 V/A | 10 µs | |
| LCA-100K-50M | 100 kHz | 30 fA/√Hz | 5 x 107 V/A | 4 µs | |
| LCA-200K-20M | 200 kHz | 40 fA/√Hz | 2 x 107 V/A | 2 µs | |
| LCA-400K-10M | 400 kHz | 65 fA/√Hz | 1 x 107 V/A | 1 µs | |
NOTE: Bandwidth and frequency response are independent of detector capacitance. Guaranteed and 100 % tested up to 10 nF for each amplifier (up to 1 nF for LCA-400K-10M).
Output voltage ±10 V @ >10 kΩ load. Offset adjustable by trimpot. Output short-circuit protected. Power supply via 3-pin LEMO® socket. A mating connector is provided with the device. Optional power supply PS-15 available. For further information please view the datasheet or contact FEMTO.
Why use a transimpedance amplifier module?
Unlike desktop amplifiers, preamplifier modules provide gain close to the detector before the signal-to-noise ratio significantly decreases due to cable capacitance and noise pickup. Signal processing and measuring after pre-amplifying has no effect on the signal/noise performance.
Gain and noise
In order to achieve an extremely low noise performance very high gains were chosen, while nevertheless minimising the associated bandwidth reduction.
Thus, as a result of our sophisticated development efforts we can offer a professional high-end current amplifier line. The noise performance of our products surpasses by far that of conventionally designed OpAmp current-to-voltage converters at the corresponding bandwidth.
Bandwidth and frequency response
With common circuits, as can often be found in the application manuals of operational amplifier manufacturers, the bandwidth and thus the measurement speed usually decreases significantly at high gain values. Even with medium gains, only a few Hz bandwidth is usually achieved and modulated or time-resolved measurements are almost impossible. FEMTO has therefore spent many years developing special circuit technologies that, in conjunction with specially selected components, deliver exceptionally good results. We can offer professional current amplifiers that really deserve the designation ultra-low noise. The noise behaviour far exceeds that of conventionally developed current-to-voltage converters with operational amplifiers with a comparable bandwidth. The LCA series is unrivalled; it is the lowest-noise current-to-voltage converter modules currently available on the market.
In addition to low noise, high bandwidth and lots of gain, FEMTO current amplifiers show almost ideal behaviour in a wide variety of applications, without requiring any special adaptations or frequency compensation measures. Bandwidth and frequency response remain constant, regardless of the connected source capacitance up to values of 10 nF. No gain peaking will occur.
Preamplifiers for lock-in amplifiers
Lock-In-Amplifiers usually have a special current input. By using instead a low noise preamplifier in noise limited experiments even the sensitivity and speed of a DSP Lock-In is strongly increased. Femtoampere currents can then be measured within a few milliseconds.
Applications
- Current to voltage converter for current measurement
- Photodetector amplifier
- Spectroscopy
- Scanning tunnelling microscopy
- Ionisation detectors
- Pyro- and piezoelectric detectors
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