New low-dropout current DAC improves power efficiency and noise control in external-laser optical modules for AI data-centre interconnects.
A new multi-channel current digital-to-analog converter (IDAC) by PhotonIC Technologies, designed for external laser systems in AI data-centre optics, promises improved power efficiency and signal integrity in next-generation pluggable optical modules. Developed by PhotonIC Technologies, the device targets external-laser small-form-factor pluggable (ELSFP) modules for high-speed optical interconnects.
The new chip is built to operate inside optical architectures such as Linear-Pluggable Optics (LPO), Co-Packaged Optics (CPO), and Near-Packaged Optics (NPO), where external laser sources must deliver extremely stable continuous-wave optical output while maintaining strict power and thermal budgets. In these systems, maintaining a high power-supply rejection ratio (PSRR) while operating at very low dropout voltage is a major design challenge.
The key features are:
- Wide input voltage range: 0.8 V – 2.2 V
- 8-channel programmable IDAC with flexible channel combinations
- Up to 0.5 A per channel or 4 A combined output
- 12-bit constant current control with integrated 11-bit SAR ADC for monitoring
- Built-in protection: over-voltage, laser short/open detection, and thermal shutdown
Traditional current-driver architectures typically experience significant PSRR degradation when dropout voltage is reduced. As a result, system designers often increase voltage headroom to maintain signal stability, which leads to higher power consumption and more complex thermal management. The new architecture addresses this limitation with a patented design that maintains high PSRR performance even at ultra-low dropout levels.
The device integrates eight independently controllable current DAC channels, allowing engineers to configure multiple channel combinations depending on the drive current requirements of various continuous-wave (CW) laser implementations. This flexibility enables optical module designers to adapt the same chip across different laser configurations used in high-speed data-centre links.
Beyond current control, the chip also integrates monitoring and protection capabilities required for reliable laser operation. An onboard successive-approximation-register (SAR) ADC enables monitoring of laser voltage and temperature, while built-in fault detection protects against conditions such as over-voltage, laser short circuits, open circuits, and thermal overload.
The company plans to demonstrate the device during Optical Fiber Communication Conference 2026 at the Los Angeles Convention Center. Alongside the new IDAC, the firm will also showcase several optical communication chipsets, including VCSEL transmitter and receiver solutions, active copper cable redriver ICs, and next-generation electrical ICs targeting 200-Gbps optical networking platforms.As AI clusters and hyperscale data centers continue to demand higher optical bandwidth and lower power consumption, component-level innovations such as high-efficiency current drivers are becoming increasingly critical to the design of scalable optical interconnects.
