DAYA Electronics – Successful Application Cases of MOSFETs in the Optical Module Sector
Taiyuan Electronics is a leading supplier of MOSFETs, offering a comprehensive range of high-quality products—including various low-voltage, low-signal, and low-Rds(ON) surface-mount MOSFETs designed for SFP, SFP+, QSFP28, and 400G/800G high-speed optical modules—along with internal power supplies, hot-swap protection circuits, laser driver circuits, and protection circuits. These products have been mass-provided to numerous domestic optical module manufacturers. Below are four typical implementation cases.
Case 1: Gigabit SFP Optical Module (1.25G – Data Center Access / 5G Backhaul)
- Application Scenario: Power Input Reverse-Connection Protection + Hot-Swap Surge Protection Circuit
- Challenges: SFP optical modules support hot-swapping, which can easily induce voltage surges or pose a risk of power reverse-connection during insertion or removal; the internal space within the module is limited, and the PCB layout is compact, necessitating small-package, low-loss MOSFETs to prevent excessive module temperature rise.
- Taiyuan's MOSFET Solution: A P-channel MOSFET packaged in SOT-23 form factor was selected. This device features a low gate turn-on voltage, enabling reliable conduction even with a 3.3V power supply; its low Rds(ON) results in a small on-resistance and lower power consumption compared to diode-based protection solutions.
- Implementation Results: The solution ensures stable operation of the DDM digital diagnostic system, with no failures observed after thousands of hot-swapping cycles and excellent long-term thermal management; it has been deployed in large quantities for 5G backhaul and data center access gigabit optical modules by telecom operators.
Case Study 2: 25G SFP28 Optical Module (Data Center Interconnection)
- Application Scope: Internal POL step-down power supply switch for powering TOSA, ROSA, and TIA amplifiers.
- Technical Challenges: The 25G high-speed optical module features multiple low-voltage power supply paths internally; power supply ripple can directly interfere with high-speed optical and electrical signals. It is essential to balance the MOS switch switching speed and gate charge (Qg) to minimize EMI noise while simultaneously managing heat dissipation.
- TAIYUAN MOS Solution: An N-channel low-voltage logic-level MOS transistor with a small DFN package, combining low Qg and low Rds(on) characteristics, making it suitable for low-power Buck power supplies.
- Implementation Results: Low power conversion ripple ensures no interference with high-speed reception signals, thereby guaranteeing stable optical sensitivity performance; this solution has been successfully deployed in mass production for 25G interconnection optical modules used in cloud service provider data centers.
Case Study 3: 400G QSFP-DD High-Speed Optical Module (AI Computing Cluster Interconnection)
- Application Scope: Power domain switching, load switching, and power-on timing control.
- Technical Challenges: The 400G high-speed optical module features multiple channels and higher power consumption; multiple power domains require time-sharing power-on sequencing to prevent laser and TIA chip damage caused by power-on surges; the high-density packaging imposes strict constraints on device size and demands extremely high device consistency.
- TAIYUAN MOS Solution: A TAIYUAN-sourced surface-mount N/P-channel MOS transistor combination solution featuring excellent gate characteristic consistency, support for direct MCU-driven control, precise management of the power-on timing for each power supply path, and effective suppression of power-on surge currents.
- Implementation Result: Solves the issue of power-on surge events across multiple power domains; the module demonstrates stable performance during prolonged 70°C high-temperature aging tests; designed for the AI Server GPU Interconnect 400G Optical Module Project.
Case Study 4: Industrial-grade SFP optical module (Power/Electrified Rail Transit Communications)
- Application Scenario: Laser driver circuit + Overcurrent protection switch.
- Challenge: Industrial environments feature significant temperature variations and strong electromagnetic interference, imposing stringent requirements on the wide-temperature stability and reliability of the components; overcurrent in the laser driver circuit can easily lead to the burnout of optical components.
- Taiyuan MOS Solution: Wide-temperature, low-voltage MOSFETs with minimal Rds(ON) variation across high-and low-temperature ranges and stable switching characteristics, suitable for use as current-limiting switches in laser driver circuits.
- Implementation Result: Stable operation across a wide temperature range of -40°C to 85°C; strong interference immunity; mass deployment in industrial optical modules for substation and rail transit signal transmission applications.
Selection Summary
When selecting internal MOSFETs for optical modules, focus on three key factors: compact package size, low on-resistance, and appropriate gate charge; additionally, ensure high consistency across device batches to meet requirements for long-term aging, high/low-temperature, and hot-swappable reliability testing. As a leading MOSFET supplier, Taiyuan Electronics offers a comprehensive range of high-quality products and can provide sample testing and technical support, covering all MOSFET requirements—from low-speed SFP modules to high-speed 400G/800G optical modules—providing a one-stop solution for component sourcing for optical module power supplies, protection, and driver circuits.
