RS31389 - Stackable 16V, 60A eFuse

RS31389 60A Stackable eFuse for Scalable Point-of-Load Protection

Scalable Protection for High-Current AI Power Rails

The RS31389 is a 2.97V to 16V stackable 60A eFuse designed to protect intermediate bus and point-of-load (POL) power rails in AI servers, accelerators, networking equipment, storage systems, and high-performance computing platforms. Integrating an ultra-low 0.8mΩ MOSFET, adjustable current limiting, precision current monitoring, and comprehensive circuit protection, the RS31389 safeguards high-current power rails while minimizing power loss.

Unlike conventional eFuses that are limited to a fixed current rating, the RS31389 supports a scalable architecture. It can operate as a standalone 60A eFuse or multiple RS31389 devices can be connected in parallel using a leader-follower architecture to increase system current capability. This provides a simple path to protecting the ever-increasing current requirements of modern AI processors, GPUs, ASICs, and FPGA-based accelerator platforms.

For applications requiring digital configuration, telemetry, and intelligent fault management, the RS31389 can also be paired with the RS31390, adding PMBus® communication while maintaining the same scalable parallel architecture.

Optimized for Intermediate Bus and Point-of-Load Protection

Modern AI servers typically distribute power through a multi-stage architecture. A 48V distribution bus feeds an intermediate bus converter (IBC), which generates lower-voltage intermediate rails for multiphase voltage regulators powering processors and accelerators.

The RS31389 is optimized to protect these intermediate bus and point-of-load power rails by providing:

• Controlled startup and inrush current limiting
• Continuous overcurrent protection
• Fast short-circuit protection
• Overvoltage protection
• Overtemperature protection
• Automatic fault recovery or latch-off operation (depending on system implementation)

Its low on-resistance minimizes power dissipation while protecting valuable downstream power converters and processors from damaging fault conditions.

Easily Scale Beyond 60A

As AI processors continue to demand higher current, designers often need significantly more than 60A of protection capability.

The RS31389 addresses this challenge by supporting parallel operation with additional RS31389 devices. Multiple eFuses can share load current while providing coordinated protection, allowing designers to increase current capability without redesigning their power architecture.

This scalable approach allows a common protection architecture to support a wide range of current requirements while reducing design complexity and shortening development time.

Add PMBus Intelligence with the RS31390

Some applications require more than analog protection.

When digital control, telemetry, and remote configuration are needed, the RS31389 can be paired with the RS31390 intelligent eFuse.

Together they provide:

• PMBus digital configuration
• Current telemetry
• Fault reporting
• Digital diagnostics
• Configurable protection thresholds
• Scalable high-current protection

This allows designers to begin with a cost-optimized analog solution or deploy a fully PMBus-enabled intelligent protection system without changing the overall power architecture.

Designed for AI and High-Performance Computing

The RS31389 is well suited for protecting high-current power rails in:

• AI servers
• GPU accelerator cards
• AI inference and training systems
• High-performance computing (HPC)
• Networking switches and routers
• PCIe accelerator cards
• FPGA and ASIC power rails
• Storage systems
• Telecom infrastructure
• Industrial computing equipment

Its combination of low-loss operation, scalable architecture, and comprehensive protection makes it an ideal solution for today’s demanding computing platforms.

Part of Reed Semiconductor’s Scalable eFuse Family

The RS31389 is part of Reed Semiconductor’s comprehensive eFuse portfolio supporting every stage of modern AI power architectures.