Ultra Low Noise Transimpedance Amplifier (Current Amplifier) LCA


  • 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
Model3 dB
(DC …)
Noise CurrentTransimpedance
Rise/Fall TimeDatasheet
LCA-2-10T 2 Hz0.18 fA/√Hz1012 und 1013 V/A200 msDownload
LCA-30-1T30 Hz0.5 fA/√Hz1 x 1012 V/A12 msDownload
LCA-30-200G30 Hz0.5 fA/√Hz2 x 1011 V/A12 msDownload
LCA-200-100G200 Hz1.5 fA/√Hz1 x 1011 V/A2 msDownload
LCA-200-10G200 Hz1.5 fA/√Hz1 x 1010 V/A2 msDownload
LCA-1K-5G1 kHz3 fA/√Hz5 x 109 V/A400 µsDownload
LCA-2K-2G2 kHz4.5 fA/√Hz2 x 109 V/A200 µsDownload
LCA-4K-1G4 kHz6.5 fA/√Hz1 x 109 V/A100 µsDownload
LCA-10K-500M10 kHz10 fA/√Hz5 x 108 V/A40 µsDownload
LCA-20K-200M20 kHz14 fA/√Hz2 x 108 V/A20 µsDownload
LCA-40K-100M40 kHz19 fA/√Hz1 x 108 V/A10 µsDownload
LCA-100K-50M100 kHz30 fA/√Hz5 x 107 V/A4 µsDownload
LCA-200K-20M200 kHz40 fA/√Hz2 x 107 V/A2 µsDownload
LCA-400K-10M400 kHz65 fA/√Hz1 x 107 V/A1 µsDownload

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 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

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 behavior far exceeds that of conventionally developed current-to-voltage converters with operational amplifiers with a comparable bandwidth. The LCA series is unrivaled; 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 behavior 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.


  • Current to voltage converter for current measurement
  • Photodetector amplifier
  • Spectroscopy
  • Scanning tunneling microscopy
  • Ionization detectors
  • Pyro- and piezoelectric detectors

Related products / accessories

Power Supply

Low Noise Cable