Can I use the DRV200 IMON output to measure current noise or modulation?

Last updated: 2026-08-20

The IMON output is intended for DC and low-frequency monitoring of the laser current. It is not a low-noise replica of the instantaneous laser current.

IMON is generated by a separate current-monitor signal chain with its own noise floor. Its bandwidth is limited to 20 kHz. Therefore:

  • Do not infer the DRV200 output-current noise by measuring voltage noise at IMON and dividing by the current-monitor gain.
  • Current modulation above the IMON bandwidth is attenuated at IMON even when it is correctly applied to the laser current.
  • Use IMON to set or check the operating current and to observe low-frequency current variations.

The DRV200 output-current noise is characterized independently of IMON. To measure current noise, convert the output current to a voltage with a suitable precision resistor and use an external low-noise measurement chain. See Measuring the noise of laser current sources for an example measurement method.

See also

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