Introduction to TVLR

Modern data center and server compute platforms operate on sub-1V core rails, but must sustain load transitions measured in hundreds of amps per microsecond. With such a small margin for error, any deviations in voltage can cause timing errors, performance throttling, or outright system instability.

Transient load voltage regulator (TLVR) architectures are specifically designed to manage ultra-fast switching transients and improve responsiveness to sudden current demands. TLVR is a novel approach to voltage regulation at the point of load (PoL).

Design Challenges in TLVR Topologies

TLVRs work by splitting voltage regulation across multiple inductors. By distributing the inductance, the regulator can achieve a lower effective value, increase control bandwidth, and reduce response time. The result is faster settling to voltage targets even under sharp transient events. However, achieving this performance is not an inconsiderable challenge.

One of the foremost challenges is the requirement for very low inductance values to support fast transient response when switching frequencies reach up to 100 MHz. Conventional inductors are not optimized for such conditions and can cause inefficiencies or instability if used in TLVR. Similarly, low inductance values can increase current ripple and thermal stress, which complicates the balance between efficiency and reliability.

Electromagnetic interference (EMI) is also a factor. While higher switching frequencies improve bandwidth, they also radiate more noise into nearby sensitive circuits. PCIe retimers, Ethernet controllers, and switch ASICs often sit just millimeters from the voltage regulator, and EMI coupling can push systems close to compliance limits. Effective ferrite bead design and placement, therefore, become a requisite of keeping noise under control while maintaining voltage stability.

Ultra-Thin Inductors (UTL) for TLVR Applications

To mitigate these challenges, Murata has developed a line of ultra-thin inductors (UTL) for TLVR and high-frequency integrated voltage regulator (IVR) applications. These thin-film inductors are designed from the ground up to operate efficiently in the multi-MHz regime.

The benefits begin with their form factor. UTL inductors are fabricated in small, low-profile case sizes that conform to the tight z-height limits of package VRs. Available in configurations suitable for die-side, land-side, interposer-embedded, or PCB-embedded mounting, they give engineers flexibility in where and how to integrate inductance into their designs. By offering options both inside and outside the package, Murata offers a cohesive approach to TLVR layouts.

From a performance perspective, UTL inductors provide precisely the low inductance values that TLVR demands, while keeping direct current resistance (DCR) controlled to minimize conduction losses. Their thin-film construction supports stable behavior across a wide switching frequency range (i.e., from 2 MHz to nearly 100 MHz) to guarantee compatibility with modern regulators’ fast control loops.

Perhaps most importantly, Murata offers customization for UTL components. Engineers can specify requirements such as target inductance, DCR, and physical dimensions, and Murata can adapt designs to fit the exact needs of a package VR. Such tailorization means that regulators aren’t limited by passive component constraints and can achieve optimal transient performance within the processor vendor’s specifications.

Ferrite Beads for Power Integrity in TLVR

While inductors define the core of TLVR operation, ferrite beads are not to be forgotten. Their primary function is to suppress noise and stabilize rails by blocking high-frequency interference while allowing DC current to pass with minimal loss. Where load transients occur at high speed and regulators operate close to emission limits, effective ferrite beads are necessary.

Murata’s BLM31SN and BLE32 series are engineered for these conditions. Designed for super high current circuits such as CPUs, GPUs, and AI accelerators, they combine high impedance at noise frequencies with extremely low DCR on the order of 0.6 mΩ. This balance minimizes voltage drop while still filtering the unwanted spectral content generated during switching.

In addition, these beads are built to handle the thermal and current stresses that come with compact, high-density systems. With operating ranges from -55 °C to +125 °C, they maintain stability in server environments that run continuously at elevated loads. And, their compact footprints mean they can be placed close to the source of noise to maximize suppression effectiveness without consuming board real estate.

The Power of Customization

No two TLVR implementations are identical. Each processor vendor defines its own requirements for transient response, inductance, and integration. Off-the-shelf components may meet some of these needs, but more often than not, customization is necessary for regulators to achieve their full potential.

Murata supports this through a design approach that considers multiple mounting locations and integration strategies. Ultra-thin inductors can be placed die-side, land-side, or within an interposer, while embedded inductors allow top- and bottom-electrode configurations for PCB integration. For designs that favor external regulation, optimized PoL inductors are available for TLVR and multiphase topologies.

Such customization is only possible through early collaboration. By engaging with Murata during the initial stages of a board or package design, designers can secure inductors and ferrite beads that meet electrical targets while also conforming to the mechanical and thermal realities of the system. A proactive approach avoids compromises later in development, when layout constraints are locked and design flexibility is limited.

Conclusion

Transient load voltage regulators are quickly becoming a mainstay of power delivery in next-generation computing and networking devices. But, achieving reliable TLVR operation depends on component optimization at the inductor and ferrite bead level. 

Murata’s UTL ultra-thin inductors and BLM/BLE high-current ferrite beads, backed by a deep capability for customization, offer engineers the building blocks needed to design regulators that meet demanding transient and EMI requirements. With these tools, system designers can confidently support the performance of advanced processors without compromising size, efficiency, or compliance.

References

[1] Murata Ferrite Beads For Mobility

[2] TLVRs Overcome the Limits of Multi-Phase Devices Using Dual Coil Power Inductors