Features

• Input noise down to 270 fA/√Hz
• Bandwidth up to 400 MHz
• Transimpedance amplifier with gain up to 10⁶ V/A
• Flat frequency response
• Stabilized and adjustable bias voltage output for biasing external photodiodes
• EMI-shielded case

 

High Frequency - Only for Specialists?

Users of high frequency components are often confronted with problems including unwanted oscillation, poor ground shielding, nonlinearities, gain peaking and bandwidth reduction caused by poorly designed amplifiers. FEMTO High Frequency Amplifiers have been designed to eliminate such unwanted problems. Insensitive to signal source parameters and input wiring, FEMTO High Frequency Amplifiers perform meticulously within their specifications. No gain peaking, oscillation or significant bandwidth reduction will occur, even for source capacitances up to maximum 2 nF (for the HCA-1M-1M-C).

 

Band width Independent of Source Capacitance

Merely a few picofarads of source capacitance can drastically decrease the bandwidth of high frequency current amplifiers. However, FEMTO Current Amplifiers do not have this limitation and are not influenced by a wide range of source capacitances. No frequency compensation or special adaptation is needed and the bandwidth and gain are constant up to the maximum source capacitance specified for each model*.

 

"C"-Models

Amplifier models shown with an additional "C" are optimized for handling very large source capacitances up to nanofarads. They are very useful for measuring fast signals down to nanoseconds with large area detectors. For detectors with even more than 2 nF capacitance we offer custom designed models. Please contact us for details.

 

Transimpedance amplifier with Adjustable Offset and Bias Voltage

For a high degree of flexibility FEMTO's HCA transimpedance amplifiers offer precise offset and bias control by two trimpots. The wide range of the adjustable input offset current compensation preserves full dynamics even for signals with large DC-components. The voltage at the bias-output can be adjusted precisely from -12 to +12 Volts using the multi turn bias-trimpot.

 

Applications

• Current to voltage converter for current measurement
• Fast detection with large area photodiodes
• Spectroscopy
• Photodetection with PMTs and photodiodes
• Ionization detectors
• Pyro- and piezoelectric detectors

 

Model	3-dB Bandwidth (DC ...)	Noise Current [/√Hz]	Transimpedance (Gain)	Rise/Fall Time	Max. Source Capacitance	View and Download Datasheet
HCA-1M-1M	1 MHz	270 fA	1 x 106 V/A	350 ns	50 pF	191 kB
HCA-1M-1M-C	1 MHz	3.5 pA	1 x 106 V/A	350 ns	2 nF	191 kB
HCA-2M-1M	2 MHz	340 fA	1 x 106 V/A	180 ns	25 pF	191 kB
HCA-2M-1M-C	2 MHz	3.5 pA	1 x 106 V/A	180 ns	1 nF	191 kB
HCA-4M-500K	4 MHz	490 fA	5 x 105 V/A	90 ns	15 pF	191 kB
HCA-4M-500K-C	4 MHz	3.5 pA	5 x 105 V/A	90 ns	500 pF	191 kB
HCA-10M-100K	10 MHz	1.1 pA	1 x 105 V/A	35 ns	15 pF	189 kB
HCA-10M-100K-C	10 MHz	3.5 pA	1 x 105 V/A	35 ns	150 pF	191 kB
HCA-20M-100K-C	20 MHz	3.5 pA	1 x 105 V/A	18 ns	50 pF	190 kB
HCA-40M-100K-C	40 MHz	3.7 pA	1 x 105 V/A	10 ns	30 pF	189 kB
HCA-100M-50K-C	100 MHz	3.8 pA	5 x 104 V/A	3.5 ns	20 pF*	293 kB
HCA-200M-20K-C	200 MHz	4.9 pA	2 x 104 V/A	1.9 ns	8 pF*	287 kB
HCA-400M-5K-C	400 MHz	21 pA	5 x 103 V/A	1 ns	10 pF*	304 kB

 

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 influence 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 information please view the datasheet or contact FEMTO.