3a vs 5a cable (PD Protocol): What’s the difference and which one should you choose

What is the difference between 3A cable and 5A cable?

The advancement in smartphone charging technology has seen an increase in charging power from 5W to an impressive 240W. Despite the superficial similarity in the appearance of interfaces, cables, and chargers, there’s a significant disparity in performance and pricing. This is particularly evident with USB-C cables, where the cost can vary markedly, and in instances where a 100W charger fails to deliver maximum output, resulting in slower charging times.

This discrepancy can largely be attributed to the “performance grading” system inherent in standard USB-C cables, with 3A and 5A cables being the most prevalent specifications. These differences in cable specifications directly impact the charging power capability of the system.

From 5W to 240W, we found the charging speed of electronic devices is faster and faster. But it’s not easy for us to get the proper cable. Even though the appearance looks similar, the performance is completely different. For example, the cable can be divided into 3A(60W) and 5A(100W). So this article will talk about what’s the difference between them.

Different Cable types

The USB-C connector is presently the most prevalent interface for fast charging available in the market. There are various types of USB-C cables, with the primary ones being USB-C to USB-C and USB-A to USB-C. Since the USB-C to Lightning cable is not a universal option, it will not be the focus of this discussion. Instead, the article will concentrate on the more universally compatible USB-C to USB-C.

E-mark chipset

The USB Power Delivery (USB PD) and USB-C ecosystem involve three critical components: the power source (Source), the recipient of the power (Sink), and the connecting cable. Within this system, a negotiation process occurs where the connected devices use the cable to identify each other as either a charger, phone, computer, etc. This process establishes the role of each device as either the provider or receiver of power and facilitates the exchange of key information such as power and data transfer specifications.

The USB-C cable serves as an essential conduit for both power and data. Some cables include an “E-Marker” chip at the terminal that participates in this negotiation, acting as a third party to communicate capabilities.

The inclusion of the E-Marker chip is not mandatory, but it influences the safety and capability of the cable. Cables without an E-Marker chip are typically limited to a 3A current to prevent safety issues like overheating due to high resistance. Cables equipped with a 3A E-Marker chip will also max out at a 3A current transmission for the fast charging system. To achieve a higher current transmission of 5A, a cable with a 5A E-Marker chip is required.

Data cables predominantly come in two power transmission specifications: 60W and 100W, correlating with 3A and 5A cables respectively. Aside from Lightning cables, the power transmission capability of a cable is generally not directly linked to its data transfer performance. For fast charging above 60W (3A), a 100W (5A) cable is essential. Therefore, it’s crucial to read product descriptions carefully when purchasing to ensure the cable supports the desired power level; otherwise, its usage will be confined to a maximum of 60W (3A).

USB standardsData transferVoltageNo E-Makrer3A E-Marker5A E-Marker
USB 2.0480Mbps20V60W 60W100W
USB 3.0
USB 3.1 Gen1
USB 3.2 Gen2
5Gbps20V/60W100W
USB 3.1
USB 3.1 Gen1
USB3.2 Gen2
10Gbps20V/60W100W
USB 3.2 Gen2X220Gbps20V/60W100W
Thunderbolt3
Thunderbolt4
40Gbps20V//100W

3A cable

The 3A cable, a common choice in the market, typically doesn’t have distinctive markings to differentiate it by appearance or terminal design. The term “3A” refers to its maximum current carrying capacity of 3 Amps. When considering the highest voltage of 20V outlined in the USB PD3.0 standard, this cable can support fast charging up to a power output of 60W.

Most 3A cables come without an E-Marker chip. Their design and manufacturing take into account power requirements, focusing on aspects like the gold plating on contacts, the thickness of the internal wiring, and cost-effectiveness.

Fast charging at 60 watts is adequate for a range of devices including standard mobile phones, tablets, Switch gaming consoles, and ultrabooks. Due to its sufficiency for these devices, the 3A cable, which supports this power level, is often bundled with chargers rated below 60 watts and is relatively cost-effective.

Charging the phone, the above picture shows the charge of the Xiaomi 11 Pro phone, at this time, the charging current reaches 1.81A, and the power is around 15W.
Charging test for the fourth-generation 11-inch iPad Pro at 14.51V 2.09A 30.3W.
Using the original 140W charger with the cable to charge the MacBook Pro 16 M1 Max 2021 model, the power is 19.82V 2.96A 58.74W, at this time, the cable can transfer 2.96A current to support 20V3A 60W power transfer.

5A cable

The 5A cable offers nearly double the current transmission specification compared to the 3A cable, necessitating more rigorous manufacturing standards. Visually, 5A cables are usually marked with “5A” on their packaging and near the connector, making them easily distinguishable. The “5A” label signifies its capability to carry a maximum current of 5 amperes, which, when paired with the maximum voltage of 20V under USB PD 3.0 standards, enables it to support fast charging power up to 100 watts.

A 5A cable is mandated to contain a 5A E-Marker chip, which is crucial during the negotiation of power delivery between the source and the device. This chip allows the charging system to surpass the 3A current limit. The production of 5A cables is a more complex process, including the use of thicker gold plating on the connectors, broader contact shrapnel, and more substantial wire cores. Often, materials like cotton thread and lubricating powder are incorporated to increase flexibility and prevent rigidity.

With the ability to support 100W fast charging, 5A cables are optimal for high-end smartphones, high-performance laptops, and devices with large power needs. Given these attributes, manufacturers tend to invest more in the design of 5A cables, focusing on durability features like abrasion resistance and tensile strength. Consequently, the price of 5A cables is higher to reflect these enhancements.

Using a device to check its E-Marker information, it shows that there is an E-Marker chip, the cable is the maximum power that can pass 20V/5A 100W, and the data cable, is the USB2.0 standard.
Using 100W cable you can normally charge the MacBook Pro 2018 (13″) with a charging voltage of about 20.29V, a current of about 2.41A, and a charging power of about 48.92W.
Using100W cable with the Apple 87W charger to charge the customized 100W mobile power, the voltage is 20.24V, the current is about 4.44A, and the charging power is up to 90.07W, which has exceeded the maximum output power of the charger, and the cable is in normal working condition.

Comparison of 3a and 5a Cables

The comparison between 3a and 5a USB cables primarily revolves around two critical aspects: power delivery capabilities and device compatibility. These differences are essential to understand for consumers aiming to make an informed choice based on their specific needs and the requirements of their devices.

Power Delivery

The most significant difference between 3a and 5a cables is their capacity for power delivery. A 3a cable is capable of delivering up to 3 amps of power, making it suitable for charging smartphones, tablets, and other small devices efficiently. On the other hand, a 5a cable can deliver up to 5 amps of power, which is ideal for more power-hungry devices such as laptops or devices that support fast charging. The increased amperage of 5a cables means they can charge compatible devices more quickly than 3a cables, assuming the device and the power source (such as a charger or power bank) support the higher current.

Device Compatibility

When it comes to compatibility, 3a cables are generally more versatile. They are compatible with a wide range of devices, including almost all smartphones and tablets, without the risk of delivering too much power. This universal compatibility makes 3a cables a safer, more reliable choice for users with multiple types of devices. Conversely, while 5a cables are beneficial for devices that can take advantage of their higher power delivery, not all devices are designed to handle 5 amps. Using a 5a cable with a device that cannot support this level of current does not typically pose a risk of damage, as the device will only draw the amount of power it needs, but it means the additional capacity of the cable may go unused.

Pros and Cons

The choice between 3a and 5a USB cables involves weighing their advantages and disadvantages, which are influenced by their charging capabilities and compatibility with devices. Understanding the pros and cons of each can help users decide which cable best suits their needs.

Pros of 3a Cables:

  1. Universal Compatibility: 3a cables are compatible with a wide range of devices, from smartphones to tablets, making them a versatile option for most users.
  2. Sufficient for Everyday Use: For regular charging needs, such as overnight charging or maintaining battery life throughout the day, 3a cables provide adequate power.
  3. Wider Availability: Due to their common use, 3a cables are readily available in the market, often at a lower price point than their 5a counterparts.

Cons of 3a Cables:

  1. Slower Charging: Compared to 5a cables, 3a cables charge devices more slowly. This can be a significant drawback for users who require quick charging to accommodate busy schedules.
  2. Limited for High-Power Devices: For devices that require more power, such as certain laptops or fast-charging-enabled smartphones, 3a cables may not deliver optimal charging speeds.

Pros of 5a Cables:

  1. Fast Charging: The primary advantage of 5a cables is their ability to charge compatible devices rapidly, significantly reducing charging time for high-power devices.
  2. Ideal for High-Power Devices: Devices that require a higher power input, including fast-charging smartphones and laptops, benefit from the enhanced power delivery of 5a cables.

Cons of 5a Cables:

  1. Limited Compatibility: Not all devices are designed to handle the higher amperage of 5a cables, which can limit their usability across a range of devices.
  2. Potentially Unnecessary for Smaller Devices: For devices that do not support fast charging or do not require a high power input, 5a cables may offer more power than needed, leading to an unnecessary expense.
  3. Higher Cost: Generally, 5a cables are more expensive than 3a cables, reflecting their advanced charging capabilities and potentially higher manufacturing costs.

Factors to Consider When Choosing

Device Requirements

The most crucial factor is your device’s power requirements. Devices designed to charge at a higher amperage will benefit from a 5a cable, as it can deliver power more efficiently and quickly. Conversely, for devices with lower power requirements, a 3a cable is sufficient and can provide a safe and effective charging solution.

Desired Charging Speed

If quick charging is a priority for you, particularly for devices that support fast charging technologies, a 5a cable may be the better choice. It is designed to handle higher power delivery, which can significantly reduce charging times. However, if charging speed is not a critical concern, a 3a cable can perform adequately for most standard charging needs.

Quality and Durability

The build quality of the cable affects not only its longevity but also its safety and performance. High-quality cables, regardless of whether they are 3a or 5a, are constructed with better materials that can withstand wear and tear, resist tangling, and offer more reliable conductivity. It is worth investing in cables that have robust construction and are from reputable manufacturers to ensure that they deliver consistent performance over time.

User Experiences

User testimonials and reviews provide valuable insights into how these cables perform in real-world scenarios. Many users have found that 5a cables are highly efficient for fast charging, making them ideal for users who value speed and have compatible devices. These cables are particularly appreciated by those who need to quickly charge their devices or have high-power devices like laptops that can take advantage of the faster charging capability.

On the other hand, 3a cables are praised for their versatility and reliability in everyday use. They are often preferred by users who do not require fast charging capabilities but still want a dependable cable that can charge their devices safely and effectively. The widespread compatibility of 3a cables makes them a versatile choice for a broad range of devices.

Price Comparison

In terms of pricing, 5a cables tend to be more expensive than 3a cables due to their higher power delivery capabilities and, in some cases, more sophisticated construction designed to support fast charging technologies. However, for users who need the enhanced charging speed and performance that 5a cables offer, the higher price can represent a good value, providing a noticeable improvement in charging efficiency and time savings.

In contrast, 3a cables are generally more affordable and offer good value for users with standard charging needs. They are a cost-effective solution for everyday charging of smartphones, tablets, and other devices that do not require the high power delivery provided by 5a cables.

Choosing between a 3a and a 5a USB cable involves considering these factors in relation to your specific needs and preferences. Assessing the device requirements desired charging speed, and the importance of cable quality and durability will help guide you to the appropriate choice, ensuring that you get the best possible performance and value for your investment.

Conclusion

Understanding the difference between 3a and 5a cables is key to choosing the right one for your device. Consider the device’s requirements, desired charging speed, and the quality of the cable to make an informed decision.

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