LED Rise and Fall-Time Test Modules

The ability to precisely and consistently measure rise and fall time for LED devices is critical for product developers and associated applications having time-dependent parameters in their product design.

The Gamma Scientific solution accurately captures these time values via a high speed sensor circuit and proprietary software.

One of the challenging issues with proper rise time is to counter the impact that the power supply introduces into the measurement. Our custom design brings LED current and voltage to 100% the moment the trigger-on command is issued, allowing rise and fall-time analysis to include only the response of the LED itself. This allows our system to resolve rise time values as low as 10 ns.


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Exceptional Precision & Repeatability for LED Testing Applications

  • Windows GUI with multiple panes for display of test data for multi-channel LED chips
  • Controls main power supply (SMU), LED switch, and digital oscilloscope
  • Triggers events via PCIe DIO Card
  • LED test current monitor & adjusted via software controls
  • Acquires / analyzes digitized oscilloscope trace with ~ 100K data points per LED pulse
  • LED test parameters saved / restored from configuration / test recipe files
  • Adjustable pass / fail criteria
  • Test data logging
  • Adjustable noise filtering

Hardware Specifications

LED Forward Voltage (Vf) (1)

12 VDC

LED Forward Current, Maximum (1)

0.5 A

Test Pulse Length (1)

1000 nsec

Rise / Fall Time Resolution

5 nsec

Rise / Fall Time Minimum

5 nsec

Photodetector Spectral Response (2)

400 to 1000 nm

Photodetector Rise Time (2)

2 nsec

Digital Oscilloscope, Bandwidth

500 MHz

Digital Oscilloscope, Input Channels

2 to 4

Digital Oscilloscope, Rise Time @ 50 Ohm

< 1 nsec

LED Switch, Channels (3)



Gamma Scientific Proprietary Code

(1)Adjustable via control software application

(2)Battery powered for noise control purposes

(3)LED current feedback monitors are multiplexed with two oscilloscope input channels

Custom configurations available

Specifications are subject to change without notice.

Systems are configured as customer needs dictate.  This is a sample system only.