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Ultra Low Noise Current Amplifier, Preamplifier

  • Ultra low noise – input noise down to .2 fA/Hz
  • Bandwidth up to 400 kHz
  • Gain up to 1013 V/A
  • Flat Frequency Response
  • EMI-Shielded Case

Why use a Preamplifier 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 preamplifying has no effect on the signal/noise performance.

Gain and Noise
In order to achieve an extremely low noise performance in the LCA current amplifier very high gains were chosen, while nevertheless minimizing 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
FEMTO ultra low-noise current amplifiers show almost ideal behavior without the need for special adaptations or frequency compensations. Bandwidth and frequency response are independent of source capacitance up to 10nF. No gain peaking will occur.

Preamplifier for Lock-Ins
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.

Photodetection with PMTs and Photodiodes
Scanning Tunneling Electron Microscope
Ionization Detectors
Pyro and Pyroelectric Detectors

Variable Gain Current Amplifier Comparison

Ultra low noise amplifier selector:

Model3-dB Bandwidth
(DC ...)
Noise Current
Transimpedance (Gain) [V/A]Rise/Fall Time
DDPCA-300Variable - see DDPCA product page
DLPCA-200Variable - see DLPCA product page
LCA-2-10T2Hz0.2 fA1x1012 and
1 x 1013 switchable
LCA-30-1T30 Hz0.5 fA1 x 101212 ms
LCA-30-200G30 Hz0.5 fA2 x 101112 ms
LCA-200-100G200 Hz1.5 fA1 x 10112 ms
LCA-200-10G200 Hz1.5 fA1 x 10102 ms
LCA-1K-5G1 kHz3 fA5 x 109400 μs
LCA-2K-2G2 kHz4.5 fA2 x 109200 μs
LCA-4K-1G4 kHz6.5 fA1 x 109100 μs
LCA-10K-500M10 kHz10 fA5 x 10840 μs
LCA-20K-200M20 kHz14 fA2 x 10820 μs
LCA-40K-100M40 kHz19 fA1 x 10810 μs
LCA-100K-50M100 kHz30 fA5 x 1074 μs
LCA-200K-20M200 kHz40 fA2 x 1072 μs
LCA-400K-10M400 kHz65 fA1 x 1071 μs
NOTE: Bandwidth and frequency response are absolutely independent of Detector Capacitance. Guaranteed and 100 % tested up to 10 nF for each amplifier.
Low Noise Input/Output Cable available: CAB-LN1 Low Noise Cable
Output voltage  ±10 V @ 10 kOhm load. Offset adjustable by trimpot or external control voltage. AC-Coupling optional. Output short-circuit protected. Power supply via 3-pin LEMO socket. A mating connector is provided with the device. Optional power supply PS-15 is available. For further information, please view datasheets.
FEMTO Product Catalog

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