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»High-Speed Current Amplifier

  • Input noise down to 270 fA/√Hz
  • Bandwidth up to 400 MHz
  • Gain up to 10° V/A
  • Flat frequency response
  • Stabilized and adjustable bias voltage output for biasing external photodiodes
  • EMI-shielded case


  • Fast detection with large area photodiodes | Spectroscopy | Photodetection with PMTs and photodiodes | Ionization detectors | Pyro- and piezoelectric detectors


Output voltage ±1.5 V, @ 50 Ω load. Offset adjustable by trimpot. Output short-circuit protected. Adjustable bias-output (−12 V … +12 V) for biasing photodetectors. 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.

NOTE: The maximum detector capacitance listed above means that up to this value the specified −3dB-bandwidth (±15 %) is guaranteed. Larger capacitances are also possible, but will slightly influ- ence the bandwidth and frequency response.

*For the ultra fast models HCA-100M-50K-C, HCA-200M-20K-C and HCA-400M-5K-C a reduction in bandwidth up to 25 % of the nominal values might occur if the source capacitance reaches the above noted maximum source capacitance values. Especially for these models short cables at the input and the use of low capacitance sources is of major importance. For further infor- mation please view the datasheet or contact FEMTO®.


−3 dB Band-width (DC …)Noise Current [/√Hz]Transim-pendance(Gain)Rise/Fall TimeMax Source Capacitance
HCA-1M-1M 1 MHz270 fA 1 x 10° V/A350 ns50 pF
HCA-1M-1M-C1 MHz 3.5 pA 1 x 10° V/A350 ns2 nF
HCA-2M-1M2 MHz 340 fA1 x 10° V/A180 ns25 pF
HCA-2M-1M-C2 MHz 3.5 pA 1 x 10° V/A180 ns1 nF
HCA-4M-500K4 MHz490 fA5 x 10° V/A 90 ns 15 pF
HCA-4M-500K-C 4 MHz 3.5 pA5 x 10° V/A90 ns 500 pF
HCA-10M-100K10 MHz1.1 pA1 x 10° V/A35 ns 15 pF
HCA-10M-100K-C10 MHz3.5 pA 1 x 10° V/A 35 ns150 pF
HCA-20M-100K-C20 MHz3.5 pA1 x 10° V/A 18 ns 50 pF
HCA-40M-100K-C40 MHz3.7 pA1 x 10° V/A10 ns 30 pF
HCA-100M-50K-C 100 MHz3.8 pA 5 x 10° V/A3.5 ns20 pF*
HCA-200M-20K-C200 MHz4.9 pA2 x 10° V/A1.9 ns8 pF*
HCA-400M-5K-C400 MHz21 pA5 x 10° V/A1 ns10 pF*



Technical Brochure