Sunlord WCX Ultra-Low-Voltage Molded Power Inductors for 800G/1.6T AI Optical Modules

AI optical modules are moving from 800G to 1.6T, and the power stage is becoming the bottleneck. A 1.6T DSP rail can demand 0.8 V at 15–20 A in a package smaller than a thumbnail, while the module housing leaves almost no room for heat spreading. Traditional power inductors struggle to deliver both high saturation current and low DCR in a 0420/0430 footprint. Sunlord's WCX series was developed for this exact problem: an ultra-low-voltage molded construction that combines high current, low loss and rugged reliability in a compact SMD package.

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1. Why 1.6T Optical Modules Need a Different Power Inductor

At 800G, a typical DSP rail may run 10–15 A; at 1.6T, the same rail can exceed 20 A during burst traffic. The inductor must hold inductance at peak current, keep DCR low to limit I²R loss, and survive repeated thermal cycling. At the same time, QSFP-DD and OSFP modules keep shrinking the PCB area around the DSP, so the inductor must fit a 0420 or 0430 case.

In practice, three requirements collide: high current, low loss and small size. A part that satisfies only one of them forces a compromise elsewhere — extra copper area, a larger heatsink, or a derated rail.

• High current: 1.6T DSP rails can reach 15–20 A, with transient peaks above the steady-state value.
• Low loss: every milliohm of DCR becomes heat inside a sealed optical module; efficiency and thermal margin depend on it.
• Small size: 0420/0430 footprints are often the only space available next to the DSP and the optical engine.

2. WCX Series: Ultra-Low-Voltage Molding for High Current in 0420/0430

WCX uses Sunlord's ultra-low-voltage molding process. Lower molding pressure protects the coil during encapsulation, reducing the risk of open/short failures associated with conventional high-pressure molding. The result is a molded inductor that combines high saturation current and low DCR in a compact 0420/0430 package.

Representative WCX parts target the 0.8 V/15–20 A DSP rails in 1.6T modules. For other inductance values and full datasheets, contact YQM.

Note: “—” means the value depends on the exact ordering code and test condition. Request the full datasheet and verify Isat/Irms at your operating temperature.

3. A Complete Sunlord Passive Chain for Optical Modules

An optical module is not just one inductor. Sunlord offers a full passive chain for the power stage, laser driver and optical transceiver, so a design team can source the critical passives from one supplier and reduce qualification overhead.

• WCX / MWTP / MWTC: molded and assembled power inductors for compact, high-current rails.
• MWPH / MWPU: power inductors for laser-driver and transceiver supply rails.
• MZAH / MZOH: high-frequency beads for BIAS-T and RF isolation.
• A*Z-H2T: anti-sulfur beads for harsh, sulfur-containing environments.

Figure 1: Sunlord molded power inductor — representative image; the exact WCX package differs. Source: YQM product library.

4. BIAS-T Filter Design: Choosing L1 and L2

In a BIAS-T network, L1 isolates the low-frequency bias from the RF path, while L2 suppresses high-frequency noise. A common starting point is a 1005/1608 ferrite bead for L1 (200 kHz–100 MHz) and a 0603 high-frequency bead for L2 (100 MHz to tens of GHz). The MZAH0603D901TF offers 1500 Ω at 700 MHz with a 20 MHz–37.4 GHz bandwidth and a current rating of at least 100 mA.

5. Reliability in Sulfur-Rich and High-Humidity Environments

Sulfur-containing environments can cause silver migration and open-circuit failures in ordinary beads. Sunlord's anti-sulfur beads use nano ferrite and an Ag + Cu/Ni/Sn termination to block sulfur attack, supporting long-term reliability in high temperature/humidity and industrial environments. For optical modules deployed in telecom cabinets, outdoor enclosures or industrial sites, this is an important part of the passive BOM.

6. Selection Checklist for 800G/1.6T Designs

7. FAQ

Q: What is the difference between Isat and Irms?

A: Isat is the current at which inductance drops; Irms is the current that causes a specified temperature rise. Check both at the operating temperature.

Q: Can WCX replace a conventional molded inductor?

A: Compare footprint, inductance, DCR, Isat/Irms and thermal performance, then validate on your board. The 0420/0430 footprint is designed for compact optical modules.

Q: Do you have samples?

A: Yes. YQM provides samples, datasheets and FAE support for volume programs.

Q: Is WCX automotive qualified?

A: For automotive-grade requirements, contact YQM to confirm the qualified part number and documentation.

Q: How do I choose L1 and L2 for BIAS-T?

A: L1 handles low-frequency bias; L2 suppresses high-frequency noise. Use the table above as a starting point and verify with your RF team.