New Class of Silicon Capacitor Tightens Voltage Regulation for AI Chips

Power integrity is all about delivering appropriate power to a processor or other load to maintain proper and reliable operation under dynamic loading conditions. Feeding power from one end of the power delivery network (PDN) to the other—and doing it efficiently—is no easy feat. But new power-hungry AI accelerators and high-end systems-on-a-chip (SoCs) are making everything about it more complex.

Empower Semiconductor is tackling the difficulties of AI power delivery with its latest and largest silicon capacitor for high-speed decoupling: the EC1005P. Called ECAPs, these silicon capacitors complement Empower's existing line of integrated voltage regulators (IVR). An IVR contains the entire voltage regulator in a single chip, giving you the ability to put it in very close proximity to the load or even inside the same package.

Voltage regulators are one of the core building blocks of any PDN, and they serve as tiny power stations to control and condition power to the point of load (PoL). Empower’s IVRs can switch at 100X higher frequencies than existing solutions, giving them a faster transient response and higher bandwidth. Thus, they can adjust the supply voltage to the load more quickly than other technologies.

While the IVR uses its ultra-fast response times to regulate the voltages entering the processor more tightly, they typically must be paired with “decoupling” capacitors or smooth out the power racing into a processor. Usually, standard MLCCs are used to supply high transient currents to the SoC and reduce power ripples and other anomalies that can disrupt the supply voltage to the processor and negatively impact the system's performance. But Empower has rolled out a family of silicon capacitors that can play the same role.

The new EC1005P features ultra-low impedance up to 1 GHz, plenty for high-performance computing (HPC) and AI silicon. According to Empower, the ECAP features “close-to-ideal” parasitic parameters, enabling these power-hungry chips to operate with reduced voltage margining, ultimately reducing power at the system level. The silicon capacitor is so low-profile it can be embedded directly into the substrate or interposer of any SoC.

The device fills the decoupling gap over the “last inch” of the PDN between the voltage regulators and SoC supply pins. Said Mukund Krishna, Empower’s head of product marketing: “It is becoming increasingly difficult to reach the level of power integrity and voltage regulation that these devices require with conventional MLCCs.” Leveraging Empower’s ECAP technology, the new EC1005P can replace up to several MLCCs at the same time.

The EC1005P stands out from other technologies on the market for its ultra-low sub-1-pH equivalent series inductance (ESL) and sub-3-mΩ equivalent series resistance (ESR). It is offered in a compact 3.643- x 3.036-mm 120-pad chip-scale package (CSP). The silicon capacitor comes in a standard profile of 784-µm that can be customized for various height requirements. Since they are manufactured out of silicon, Empower’s ECAPs deliver high stability over voltage and temperature and, unlike most MLCCs, they are not subject to derating or aging.