What is Micro USB : Pin Configuration & Its Working

The term USB stands for Universal Serial Bus and it was launched in the year 1990 to shorten the connections among different devices and computers. It is very famous because of its compatibility through several operating systems & platforms, less cost & simple to use. At present several computers are available with different USB ports like MiniUSB, Micro USB, etc

What is Micro USB?

The mini version of USB is known as Micro USB. It is used to connect mobile, compact devices like photo printers, Mp3 players, smartphones, GPS devices, and digital cameras. MicroUSB is available in three forms like MicroA, B & USB3, where MicroUSB3 is similar to MicroB however with an extra group pin on the face for twofold the wires, allowing the high speed of USB 3. Similar to typical USB, the micro types are plug & play.

Micro USB
Micro USB

The development of USB peripheral was done jointly with IBM, Compaq, DEC, Northern Telecom, Microsoft, NEC, Intel, etc. This technology is accessible without charge for all devices and computers.
The standards of USB are developed as well as maintained through an industry body known as the USB-IF (USB Implementers Forum). In its actual specification, USB identified simply two types of connector like A & B.

Modifications within the specification & commands on makers have extended the width of connectors which are utilized for USB devices, however, the USB based products majority are still using connector interfaces of A & B.

Pin Configuration

A connector like Micro-USB is used frequently for charging the handy devices through micro-USB charging cable otherwise by interfacing mobile devices through PC. The pin configuration of Micro USB is discussed below.

MicroUSB Pin Configuration
MicroUSB Pin Configuration
  • Pin1 (VCC): It is +5 VDC and the connected wire color is red
  • Pin2 (D-): White Data – and the connected wire color is white
  • Pin3 (D+): Green Data + and the connected wire color is green
  • Pin4 (ID): Mode detects and the connected wire color is blue
  • Pin5 (GND): Ground and the connected wire color is black

MicroUSB cable utilizes four shielded wires like two wires are used for power like +5v and GND whereas the other two wires are used for differential data signals like D+ & D-.


Non-Return to Zero Invert or NRZI is an encoding system mainly used to transmit data through a sync field for synchronizing the clocks of receiver & host. In the data cable of USB, the signals like Data+ & Data- are broadcasted over a twisted pair cable.


The specifications of MicroUSB include the following.

  • Micro USB is a Type B or SMT
  • These are available as a drop-in, reverse mount & standard
  • Gender is Female
  • Contact resistance is 30mΩ at 100mA
  • The number of Pins is 5
  • Max voltage rating is 30V
  • The mating cycle is above 5k times
  • The current rating is 1A

Types of Micro USB

Micro USBs are mainly used for connecting different electronic devices such as smartphones, GPS devices & digital cameras. These types of USBs allow manufacturers to make small devices. The main function of this device is to plug N-play like a normal USB. MicroUSB are available in different types like Micro-A USB, Micro-B USB & Micro-B USB 3.0

Micro-A USB

Micro-A USB is used by current mobile devices like cell phones, GPS units, digital cameras, etc. As compared to Mini-B USB, this kind of USB cable is small in size but its transfer rate with high-speed is 480 Mbps. The design of this USB is a white container & includes five pins. This cable includes a female connector only and it is available in a rectangular shape.

Micro-B USB

Micro-B type USB is related to its Micro-A counterpart because it is also applicable in current gadgets and small electronic devices. It is smaller in size and supports different features like micro-A type. The devices like USB 1.1 & USB 2.0 include micro-B ports that seem identical.

This kind of USB includes both male & female connectors which allow various devices to use any of the two types of connection. This USB design is The design of this USB is in a black container including five pins.

Micro-B USB 3.0

This kind of USB can be found in devices that run on USB 3.0. This device is mainly designed to function through USB high-speed applications which carry data & power. But, this kind of micro USB is not incompatible with devices that work through USB 1.1 & 2.0.

As the name suggests, micro-B USB 3.0 is very similar to micro-B type USB. However, the main dissimilarity is that it includes an extra group of the pin on its face that provides it double the number of wires. This also allows USB 3.0 to work at its usual speed.

Working of MicroUSB

Micro-USBs are most widely utilized for charging smartphones, tabs, cameras, etc. Once the USB cable is connected to a power source, then power can be transferred throughout the micro USB cord to provide charging to the smartphone device.

In the case of Laptops, PCs, this is also used to connect your device to a computer to give the capability to execute some dissimilar tasks for your device from the computer, In addition to devices charging, it can be used to view files, photos, etc.

What to Consider while Selecting a Micro USB Cable?

The following things must consider while selecting a micro USB cable.

Cable Sheath/Braid

The braid or sheath mainly guards the cable & decreases the chance of breakage.


It is measured within amps & it enhances the strength of the cable & allows your device to charge quicker.

Iron Ferrite Core/ Ferrite Bead

Iron ferrite core makes the cable perform well through decreasing noise. Consecutively, it enhances the speed of data transfer.

Strain Relief

Similar to the Braid, it decreases fracture & guards the cable against fraying. If a micro USB cable has a reinforced neck then it can reduce stress & avoids break into your cable.

You’re Devices

Apart from the components, you have to consider what type of devices you’ll utilize for the cable while you purchase.

How to Use Micro USB/Micro USB Circuit

The power bank circuit is one of the applications of MicroUSB. This power bank circuit can be built with a TP4056 module, Li-ion battery & a boost converter circuit. This DIY circuit is very useful for smartphones to provide backup power.

The required components of this USB circuit are 18650 Li cell, slide switch, TP4056 Module including battery protection circuit, 3V- 5V boost converter through 1Amp current control. The circuit diagram of the power bank using MicroUSB is shown below.

Power Bank Circuit using Micro USB
Power Bank Circuit using Micro USB

The shape of the 18650 Li cell is cylindrical with 85mm height & 18mm. These cells are obtainable in various capacities based on applications. These are rechargeable cells and generate 3.7v output.
A module like TP4056A Module is an inexpensive charging solution for charging any kind of Lithium-Ion battery.

So this is a reliable option to charge any batteries with less capacity due to the simply changeable 1A o/p current control. It can be attached to any wall socket depending on the phone charger. It is designed with PMOS IC load switch architecture, therefore decreasing overall extra components.

The voltage provided by the Li battery is 3.7V only but the circuit needs 5v to operate. So a boost converter module with 3v to 5v is used. The efficiency of this module is high upto 92% & incorporated above current protection. The topology used within this is a step-up converter with Non-isolated that functions at 1MHz of a switching frequency.

The overall output power drawn out from this module is 5Watts & the o/p voltage can be changed to 12Volts by replacing a resistor within the module however the utmost current will be 400mA. But this module is accessible at a 1A 5V rating by default. This module includes a universal USB type-A so that any USB power cable can be utilized like an interface.

The operating temperature of this module ranges from -40°C to +85°C & it includes an LED indicator to specify the existing supply from the source of the battery. The LED-like red color specifies the existence of a power supply beyond the terminals.

Once the circuit connections are made according to the diagram, they should be ready to be used to charge the mobile phones.

Where to Use/Applications

The applications of Micro USB include the following.

The microUSB is used to build many embedded projects wherever power supply otherwise serial communication is necessary. Like mobile phone charging, it is also used in ESP modules, raspberry pi, etc.

MicroUSB ports are often observed in smartphones, tablets & other devices like GPS devices, video game controllers, digital cameras, etc.

The miniaturized version of USB is MicroUSB and it is designed to connect mobile devices, compact devices, etc

Thus, this is all about an overview of Micro USB and its working. A USB cable plays a key role while connecting different devices to the computer to exchange data, files, etc. And also it is used to charge the mobile phones, tabs by connecting it to laptop or computer. There are different types of USB interfaces available where Micro USB is one of the types; This interface was mainly developed to change the older interface like Mini USB.