Digital Integrating Photodiode with USB

WL-IPD4A Digital Integrating Photodiode with USB

The IPD4A is a highly-integrated, true gated charge integrator to be attached directly to up to four photodiodes. After a trigger pulse, up to four inputs are integrated simultaneously for an adjustable amount of time (boxcar integrator). The measurement is digitized with integrated 20 bit analog-to-digital converters and transferred over the USB link to a computer.

The IPD4A is compatible with a wide range of photodiodes including both silicon (Si)-based and InGaAs-based ones with various sensitive areas. While we supply the IPD4A with certain high quality detectors from Hamamatsu, you can also have the full choice over wavelength and sensitive area by specifiying or directly providing the photodiodes to be integrated into the IPD4A.

The IPD4A comes in a rugged aluminum case and is fully USB-powered.

Main Applications

  • Laser pulse monitoring and signal
    measurement in 1 kHz systems
  • Shot-to-shot pulse noise measurements
  • Digital two or four segment photodiodes
For new applications, consider using the IPD4B. It is the successor of the IPD4A with an expanded feature set.


Date: 2021/11/2
Size: 474 KB
LabView Demo
Date: 2021/2/22
Size: 109 KB


  • Simultaneous integration of up to four inputs at up to 1.15 kHz repetition rate
  • Each measurement includes signal and background acquisition
  • Adjustable gate time 8μs to 64μs with internal timer
  • High accuracy, low drift
  • Tunable full scale range 12pC to 350pC
  • Easy-to-use USB interface
  • Very high resolution due to 20 bit ADC
  • Extremely low noise integrator:
    For 350pC full scale range <10ppm noise and <20ppm noise down to 50pC full-scale range (typ.)
    This corresponds to a dynamic range in excess of 1:105
  • External trigger rising or falling edge
  • Small form factor: 60 x 83 x 21 mm (60 x 83 x 20 mm also available)
  • Comes with easy to use LabView drivers

Typical configurations

IPD4A Time Integrating Detector typical configuration
Various typical configurations of the single channel version of IPD4A.
IPD4A Time Integrating Detector alternate configuration
Alternate configuation with pluggable PCB on the bottom to mount photodiodes.

Application Notes

Femtosecond fluorescence spectroscopy based on the optical Kerr effect
R. Mundt, G. Ryseck, P. Gilch, Femtosecond spectroscopy group, Chemistry, University of Düsseldorf, Germany (May 2014)