Micro USB

What is a Micro USB Connector?

Micro USB is a type of Universal Serial Bus (USB) connector that is designed to support the USB 2.0 standard and permit data transfer speeds of up to 480 Mbps. Micro USB played an important role in helping to standardize the way portable devices transfer data and recharge battery power over the same cable.

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Techopedia Explains the Micro USB Meaning

Techopedia Explains the Micro USB Meaning

Micro USB comes in two versions: Micro-A, often found in USB On-The-Go devices, and Micro-B, commonly used for connecting smartphones to computers or chargers. While Micro USB was widely used in earlier electronics, USB Type-C has become more popular due to its reversible design, faster data transfer, and higher power delivery capabilities.

Most non-Apple portable devices manufactured after 2014 use USB Type-C connectors, but there are still some types of budget-oriented devices and specialized electronics that still use Micro USB.

How Does a Micro USB Work?

A Micro USB connector establishes a physical connection between a portable computing device and a power source, which could be an electrical outlet in a wall, a computer USB port, or a portable power station. The connector can charge the device’s battery while allowing the device to transfer data bidirectionally at the same time.

Micro-USB connectors can only be inserted into a port if they are oriented in the right direction. (This characteristic contrasts with the reversible design of newer USB-C connectors, which don’t have a right-side-up orientation.)

How Does a Micro USB Work?
Source: Amazon

Types of Micro USB

When the Micro USB specification was released in 2007 by the USB Implementers Forum, it referred to two types of Micro USBs, Type A and Type B.

The introduction of Micro USB Type A was intended to support USB On-The-Go (OTG) and allow portable devices to switch back and forth between the roles of host and peripheral devices.

Since this use case was fairly niche, vendors tended to adopt Micro USB Type B as the “new” standard for charging and data transfer over the same cable. The reality was that many devices could perform OTG functions with a Micro USB Type B port with the use of an OTG adapter.

After the introduction of USB-C in 2014, the use of Micro USB connectors in new devices began to decline, and even the introduction of Micro-B SuperSpeed connectors designed to support USB 3.0 failed to gain traction with vendors.

USB-C’s usability, power handling, and data transfer capabilities – as well as its reversible connection design, ability to carry significantly more power and data, and ability to consolidate video output, charging, and data transfers through a single Micro USB port – has made USB-C the most universally embraced connector to date.

Micro USB connections are cheaper to manufacture than USB-C connections, however, because their design is simpler. If a vendor’s priority is affordability, and their new device doesn’t require the advanced capabilities of USB-C, Micro USB can be a cost-effective choice.

Micro USB Features

Micro USB Features

Micro USB connectors are characterized by their small, durable design and ability to withstand frequent plugging and unplugging.

They can be recognized by their distinctive trapezoidal shape, which is narrower and more compact compared to previous USB types.

This type of connector has five pins.

  • Vbus Pin: Carries a 5V power supply for charging.
  • D+ Pin: Carries positive data signals.
  • D-Pin: Carries negative data signals. (The D+ and D- pins work together to facilitate USB’s differential signaling for data transfer.)
  • ID Pin: Determines whether the device acts as a host or a peripheral. (The state of this pin – whether it’s floating or grounded – is what enables OTG functionality.)
  • GND Pin: Completes the electrical circuit.

The Differences Between Mini USB, Micro USB, and USB-C

The table below summarizes the main features and differences between Mini USB, Micro USB, and USB-C connectors.

Feature Mini USB Micro USB USB-C
Introduced The early 2000s 2007 2014
Design Connections are square-like. Connections are trapezoids. Connections are oval-shaped.
Size Larger than Micro USB and USB-C. Smaller than Mini USB but larger than USB-C. Smallest of the three.
Durability Less durable than Micro USB and USB-C. Designed for up to 10,000 connect/disconnect cycles. Designed for 20,000 connect/disconnect cycles.
Data Transfer Speed Up to 480 Mbps. Up to 480 Mbps. Up to 20 Gbps.
Power Delivery Up to 500 milliamperes. Up to 1.8 amperes. Supports fast charging techniques that use up to 5 amperes of current and deliver up to 100 watts of power.
Use Cases Older digital camera and GPS units. Older smartphones, tablets, and game controllers. New smartphones, laptops, tablets, and game controllers.
Compatibility Mostly obsolete Still used in some budget-friendly devices, but being phased out. The current standard for new devices.
Connection Reversibility Non-reversible Non-reversible Reversible.
USB On-The-Go (OTG) Supported Supported Supported with more capabilities.

What is a Micro USB Cable Used For?

The uses for a Micro USB cable include:

Charging

One of the most common uses for a Micro USB cable is to charge a compatible portable device. Many devices manufactured before the widespread adoption of USB-C came with Micro USB ports, and these devices still require Micro USB cables for charging.

Data Transfer

Micro USB cables are useful for transferring photos, music, videos, and other files to and from devices that do not have a USB-C port.

USB On-The-Go (OTG) Connections

Micro USB cables can still be used to connect older peripheral devices directly to laptop computers and other portable computing devices.

Audio and Video Output

In some cases, Micro USB cables can be used with Mobile High-Definition Link (MHL) to output audio and video signals from an older mobile device to an older television or monitor.

Pros and Cons of Micro USB

The widespread use of Micro USB brought down the price of connection cables, but if the connector is inserted upside down repeatedly, it can damage the connection port.

Other pros and cons associated with Micro USB include:

Pros

  • Micro USB chargers are compatible with various portable computing devices
  • Durable design with 10,000 connect/disconnect cycles per cable
  • USB OTG support enables host and peripheral role-switching

Cons

  • Introduced in 2007, designed for USB 2.0, not compatible with the latest USB standards
  • Lack of support for video output
  • Lower power delivery capabilities compared to USB-C, leading to slower charging and data transfer
  • Phasing out in favor of USB-C in the technology industry

Apple, Lightening, and Micro USB

Until 2023, Apple used a proprietary Lightening connector rather than adopting Micro USB. In recent years, however, the European Union has become a strong advocate for a universal charging standard.

While Apple acknowledged the popularity of Micro USB by providing a Micro USB to Lightning adapter, the company continued to use its proprietary connectors until the release of the iPhone 15 series. While Apple hasn’t explicitly announced a total move to USB-C, the combination of regulatory pressure and the advantages of USB-C make it a logical path forward.

FAQs

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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.