High Speed GHz Amplifier HSA


  • Ultra-wide bandwidth from 10 kHz up to 2.5 GHz
  • Gain up to 60 dB (x 1,000)
  • Transimpedance gain with photodetectors up to 50,000 V/A
  • Very low input noise down to 310 pV/√Hz (6.2 pA/√Hz)
  • Integrated DC-current path for biased photodetector applications
  • Two identical signal outputs (HSA-Y series)
  • DC-monitor output (HSA-Y series)
Lower Cut-Off Frequency 10 kHz10 kHz10 kHz10 kHz
Upper Cut-Off Frequency 1.2 GHz2.5 GHz2.0 GHz2.2 GHz
Rise/Fall Time 290 ps140 ps180 ps160 ps
Gain 40 dB (x 100)20 dB (x 10)40 dB (x 100)40 dB (x 100) invertierend
Transimpedance*5,000 V/A500 V/A5,000 V/A5.000 V/A invertierend
Input Noise [/√Hz]**310 pV (6.2 pA)610 pV (12.2 pA)620 pV (12.4 pA)430 pV (8.6 pA)
Input VSWR1.6 : 11.23 : 11.4 : 11.25 : 1
Maximum Output Voltage
@ 50 Ω
Output VSWR1.35 : 11.4 : 12.5 : 11.4 : 1
Input/Output50 Ω, SMA50 Ω, SMA50 Ω, SMA50 Ω, SMA
Power Requirements+15 V, +140 mA, typ.+15 V, +105 mA, typ.+15 V, +125 mA, typ.+15 V, +145 mA, typ.
Case80 x 45 x 25 mm (L x W x H), weight 100 g (0.23 lb)
Lower Cut-Off Frequency 10 kHz10 kHz10 kHz10 kHz
Upper Cut-Off Frequency 1.0 GHz1.1 GHz2 GHz1.9 GHz
Rise/Fall Time 330 ps320 ps175 ps185 ps
Gain 40 dB (x 100)60 dB (x 1.000)20 dB (x 10)40 dB (x 100)
Transimpedance*5.000 V/A50.000 V/A500 V/A5.000 V/A
Input50 Ω, SMA50 Ω, SMA50 Ω, SMA50 Ω, SMA
Input Noise [/√Hz]**330 pV (6,6 pA)330 pV (6,6 pA)680 pV (13,6 pA)650 pV (13 pA)
Input VSWR1.45 : 11.4 : 11.15 : 11.2 : 1
OutputTwo identical signal outputs, 50 Ω, SMA
Maximum Output Voltage
@ 50 Ω
2.0 VPP2.3 VPP2.5 VPP1.7 VPP
Output VSWR1.6 : 11.4 : 12.5 : 11.8 : 1
Monitor Output Gain: 26 dB (x 20), transimpedance*: 1 kV/A, output voltage range: ±10 V (RLoad > 10 kΩ), bandwidth: DC - 100 kHz
Power Requirements±15 V +200 / −10 mA, typ.±15 V +180 / −10 mA, typ.±15 V +160 / −10 mA, typ.±15 V +185 / −10 mA, typ.
Case110 x 70 x 25 mm (L x W x H), weight 180 g (0.41 lb)

* Transimpedance = Gain x 50 Ω (Input Impedance)
** Input Noise Current = Input Noise Voltage ÷ 50 Ω (Input Impedance)

Integrated DC path for use with photodetectors. 8-32 and M4 mounting threads. 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!

10 kHz to 2.5 GHz

The HSA high-speed amplifiers offer a well-balanced combination of high gain, low noise and ultra-wide bandwidth making them ideal for time-resolved measurements e.g. with fast photodetectors. Wide bandwidth from kilohertz to gigahertz is very important for accurate pulse and transient measurements, especially if signals with different pulse lengths and varying decay times are processed. The outstanding HSA wide band performance is completed by the very low 1/f noise corner ensuring a true low noise performance even down to the kHz range.
Wide bandwidth, flat frequency response and low noise make the HSA amplifier series also a perfect choice for significantly increasing the sensitivity of common spectrum/network analyzers.

DC path for photodetetector bias currents

In many photodetector applications – e.g. shot-noise-limited spectroscopy, heterodyne measurements etc. – the detector is subject to relatively high cw-power generating a high level DC background current. This DC current must „see“ a low impedance path to ground, otherwise the photodetector would be back-biased resulting in significant distortions and speed limitations. All the HSA amplifiers provide a well matched 50 Ohm DC path to ground using a sophisticated coil system very similar to a so-called Bias-T design. This greatly simplifies the use of biased photodetectors together with the HSA amplifiers.


The HSA-X comes in a compact, very high quality EMI shielded case with threaded M4 and 8-32 mounting holes and is equipped with SMA input and output connectors. Various models with fixed gain of either 20 or 40 dB are available.


In addition to the features of the HSA-X the HSA-Y is equipped with a DC-monitor output useful for photodetector alignment or cw-power control or for the measurement of low frequency background signals. Furthermore, the HSA-Y features two identical signal outputs enabling signal control or triggering without the need for an external signal splitter. The HSA-Y series offers various models with a fixed gain of either 20, 40 or 60 dB.


  • Preamplifier for ultra-fast detectors (microchannel plates, photomultipliers, avalanche photodiodes and PIN photodiodes)
  • Oscilloscope and spectrum/network analyzer preamplifier
  • Time-resolved pulse and transient measurements
  • Signal booster in 50 Ω high-speed systems

Related products / accessories

Power Supply