This recently released reference design will help engineers who are designing with higher channel counts in fixed form factors in laser-drive applications
Laser-diode applications generally require a precisely controlled current to regulate the output power. It is advantageous for this current to be adjustable as output power can change over temperature. For this reason, a DAC can be used to dynamically update the forward current. In addition, a low-noise source is desired to reduce the intensity noise (instability in the output power) of a laser output.
DAC combines small size and high performance for laser drive applications
This reference design combines the small size and high performance of the newly unveiled DAC80508 8-channel, 16-bit digital-to-analog converter (DAC) with precision op-amps to create a high-density and accurate current-source solution.
The design has a maximum output current of 200 mA and allows for a minimal PVDD supply voltage to reduce power consumption for high efficiency. It also features a low current-noise output due to the low reference-voltage noise of the DAC80508 and low voltage and current noise of the OPA2376.
- Eight channels of programmable current, 200-mA range
- High channel density
- <1.5% total unadjusted error
- <120-µA offset error
- 3.4-µA RMS bandwidth-limited current noise
- Laser Drive in Optical Modules
- Tunable Laser Optical Modules