DHPCA-100 200MHz variable gain photodiode amplifier

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Femto Messtechnik has developed a variable gain transimpedance amplifier DHPCA-100 for amplifying the photo current of fast photodiodes. It offers a maximum bandwidth of 200MHz equivalent to a signal rise time of 1.8ns.

The gain is adjustable from 102 to 108 V/A allowing the measurement of currents in the sub-nano to milli-Ampere range. An adjustable voltage supply is provided as bias for external photodiodes. An integrated offset control is useful for adjusting the baseline or subtracting photodiode dark currents.


The device offers many additional features like signal filters, switchable AC/DC coupling and an integrated digital interface for remote control of all main functions by a PC. The compact amplifier housing offers EMI shielding and allows use directly at the source before the signal gets degraded by long cables or interfering equipment.


The DHPCA-100 can amplify small currents generated by high impedance sources, such as photodiodes, PMTs or ionisation detectors. Typical applications include spectroscopy, laser physics, particle detection, and general lab use.