What is LVS in SD Cards? A Guide to Low Voltage Signaling

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Introduction

As silicon foundries continue to advance SoC integration technologies toward higher performance and lower power consumption, the SD specification 6.1 officially introduces LVS (Low Voltage Signaling), supporting both 3.3V and 1.8V signal voltages. This design is fully compatible with new SoC designs while maintaining backward compatibility with traditional 3.3V host devices. Additionally, new LVS memory cards allow hosts to start in 1.8V UHS-I mode directly, delivering enhanced stability. In this article, we’ll walk you through what LVS is, how it works, and what its applications are.

What Is LVS (Low Voltage Signaling)?

Compared to standard memory cards that only support a single voltage, LVS (Low Voltage Signaling) memory cards support dual voltages and feature automatic detection. This allows the host device to enter the 1.8V UHS-I mode immediately upon startup. At the same time, LVS memory cards remain fully compatible with traditional hosts.

As next-generation platforms increasingly prioritize low power consumption, LVS memory cards offer broader compatibility across diverse application scenarios. They meet the needs of various users while enabling efficient low-power operation.

In addition, according to the SD 6.1 specification, LVS memory cards are classified into the following types based on their supported speeds:

LVS Types	Description
LV50	SD Memory cards supporting 50 MB/s UHS-I Card
LV104	SD Memory cards supporting 104 MB/s UHS-I Card
LV156	SD Memory cards supporting 156 MB/s UHS-II Card
LV624	SD Memory cards supporting 624 MB/s UHS-III Card

Source: SD Association

Key Benefits of LVS

Auto Detection Mechanism

LVS memory cards feature an auto detection mechanism. Upon startup, they detect whether the host uses 3.3V or 1.8V signaling and switch to the appropriate operating mode accordingly.

Compatibility with New-Generation SoCs and Backward Support

LVS card designs are compatible with the latest generation of SoCs while also retaining backwards compatibility to legacy 3.3V signaling hosts. This ensures no limitations due to device generation. Since SoCs typically adopt 1.8V signaling, LVS is better suited for low-voltage operation and advanced fabrication processes.

Efficient Start in UHS-I 1.8V Mode

LVS memory cards can enter 1.8V UHS-I mode immediately after power-up, effectively reducing power consumption while offering more stable and efficient performance.

Full Hosts Compatibility

To facilitate identification, LVS-compatible hosts and memory cards are marked with an "LV" symbol, helping users quickly recognize compatible products. Even if a device lacks this label, LVS cards can still operate normally.

Industrial Applications of LVS

Low-Power SoC Applications

In SoC designs using finer fabrication nodes and low-voltage power supply, the use of 1.8V signaling helps achieve goals of lower power consumption. LVS technology enables immediate entry into the 1.8V UHS-I mode after startup, skipping the traditional 3.3V initialization process, simplifying system design and improving boot efficiency.

IoT Devices

IoT devices often require long-term, stable operation and are highly sensitive to power efficiency. The low-voltage characteristics of LVS memory cards are ideal for these devices. In scenarios with frequent data read/write operations, LVS reduces power consumption and extends device battery life.

Surveillance and Security Systems

Industrial-grade DVRs and surveillance cameras often rely on microSD cards for data storage. With the need for continuous recording and real-time access, LVS memory cards operating in 1.8V mode offer stable and efficient read/write performance, reduce storage errors, and ensure secure and reliable data retention.

To meet the industrial market’s demand for low power consumption and high stability, SP’s industrial-grade SD and microSD cards fully support LVS technology. These cards are ideal for long-term, low-voltage, and high-reliability applications, ensuring more secure data retention.