MagSafe

MagSafe is a series of proprietary magnetically attached power connectors developed by Apple Inc. for Mac laptops. MagSafe was introduced on 10 January 2006, in conjunction with the MacBook Pro, the first Intel-based Mac laptop, at the Macworld Expo. The connector is held in place magnetically so that if it is tugged (for example, by someone tripping over the cable), it will be pulled out of the port without damaging the connector or the port, and without pulling the computer off its surface. A thinner and wider version, called MagSafe 2, was introduced in 2012. It was discontinued across Apple's product lines between 2016 and 2019 and replaced with USB-C. MagSafe returned to Mac laptops with the introduction of updated MacBook Pro models with MagSafe 3 in 2021.
History
The basic concept of MagSafe is derived from the magnetic power connectors that are part of many deep fryers and Japanese countertop cooking appliances since the early 2000s in order to avoid spilling their dangerously hot contents. MagSafe was introduced on January 10, 2006 in the first-generation MacBook Pro. Apple was granted for MagSafe ("Magnetic connector for electronic device", issued in 2007) as MagSafe was deemed to be a sufficient improvement due to the connector being symmetrical and reversible, and the fact that magnets within a connector are arranged in opposing polarities for improved coupling strength.
Apple phased out MagSafe with the release of the 12-inch MacBook and 2016 MacBook Pro that replaced it with USB-C for charging and data. The last product with MagSafe, the 2017 MacBook Air, was discontinued on July 9, 2019. The MagSafe connector returned in 2021 with the introduction of updated 14-inch and 16-inch MacBook Pro models.
Apple also uses the MagSafe name for a wireless power transfer and accessory-attachment standard for the iPhone based on the Qi standard, introduced with the iPhone 12 and 12 Pro.
Features
MagSafe (original)
MagSafe has connector pins that are designed so the rectangular connector can be inserted in either orientation. Originally the connector was T-shaped, with the cable directed straight out; later it became L-shaped, with the cable directed along the side of the computer, but still capable of being inserted in either orientation, unless simultaneous use of neighboring ports such as USB required directing the cable toward the rear. LEDs on both the top and bottom of the connector show green if the computer battery is fully charged and amber or red if the battery is charging. MagSafe can be found on the MacBook (2006–2011), MacBook Pro (2006 through mid-2012, non-Retina) and MacBook Air (2008–2011) notebook computers. The Apple LED Cinema Display and Thunderbolt Display include built-in MagSafe chargers.
The MacBook and the 13-inch MacBook Pro use a 60 W MagSafe charger, whereas the 15- and 17-inch MacBook Pro use an 85 W version. The MacBook Air used a lower-powered 45 W version. According to Apple, an adapter with a higher wattage than that originally provided may be used without problems.
Apple formerly offered a "MagSafe Airline Adapter" for use on certain compatible airplanes. It had a DC input (instead of AC like the original MagSafe chargers) and would power the computer, but would not charge the battery.
MagSafe 2
MagSafe 2 was introduced on the MacBook Air and MacBook Pro with Retina Display at the 2012 Worldwide Developers Conference on June 11, 2012. It was made thinner to fit the thinner laptops, and also wider to preserve magnetic grip force. It also returns to the T-shaped design that points straight out, rather than the L-shape that runs along the side of the machine. MagSafe 2 can be found on the MacBook Pro (2012–2015 Retina models) and MacBook Air (2012–2017) notebook computers.
The resulting shape is incompatible with the older MagSafe connector; Apple released a MagSafe to MagSafe 2 adapter that was also bundled with the Thunderbolt Display, which used the original MagSafe connector.
MagSafe 3
On October 18, 2021, Apple announced the M1 Pro and M1 Max 14-inch and 16-inch MacBook Pro models with MagSafe 3. MagSafe 3 is slimmer than its predecessor and connects to a power supply using a removable cable with a USB-C end. It supports up to 140 W power delivery on the 16-inch MacBook Pro with its bundled 140 W GaN power adapter which supports USB-C Power Delivery 3.1.
In June 2022, Apple announced the M2 MacBook Air with MagSafe 3, and three new color-matching cables.
Pinout
The MagSafe connector pins allow for the adapter to be inserted in either orientation. The first and second pins on each side of the central pin have continuity with their mirror pins.
The inner large pins are V+ (14.5 / 16.5 / 18.5 / 20 V DC). Measuring with no load will give 6.86 V DC for MagSafe and about 3 V DC for MagSafe 2; the full voltage is provided after a ~40 kOhm load is applied for one second.
The outer large pins are ground.
The central pin is used for communication between the computer and the power adapter following the 1-Wire protocol. The computer makes use of this to retrieve information about the power adapter and to change the color of the LEDs on the power adapter's connector. The Apple MagSafe power adapter's 1-Wire communication chip is located inside the MagSafe connector itself; the cable does not carry the data line to the power adapter enclosure.
The maximum voltage supplied is as follows:
14.5 V DC for the 45 W units supplied with MacBook Air
16.5 V DC for the 60 W units supplied with MacBook and 13" MacBook Pro
18.5 V DC for the 85 W units supplied with 15" and 17" MacBook Pro
20 V DC for the 85 W units supplied with 15" MacBook Pro Retina
The rectangular metal shroud surrounding the pins acts as shielding for the electrical pins and a ferrous attractor for the magnet in the laptop.
Third-party products
Apple does not license the MagSafe connector to third-parties, but manufacturers have devised a workaround: their MagSafe-compatible products use the actual connector from Apple's AC adapter, grafted onto their own products. Since this uses an actual Apple product, purchased legally, manufacturers believe that no licensing agreements are needed (a principle referred to as the first sale doctrine) and no patent was violated. However, in 2010 Apple still sued one such manufacturer, Sanho Corporation for selling its very popular HyperMac battery extension products which Apple claimed violated their patents. Sanho has since ceased to sell their connector cable for the HyperMac series of external batteries.
Fake MagSafe 2 chargers were offered for sale on sites such as Amazon. These chargers were sometimes unsafe, and/or had errors in their labelling, and/or behaved differently from the official product: e.g. the LEDs on the connector did not show the correct color.
Defects
Many users have reported problems with the quality of the construction of the MagSafe cords, giving the product low marks on the Apple Store's website. Common complaints included plug separating from the cord, transformer shorting, and pin springs losing elasticity.
Several methods have been devised to protect the MagSafe from failure, including wrapping the cable with tape or sliding protective plastic around the cable.
In 2008, Apple posted an official response acknowledging problems with MagSafe adapters, which include incomplete circuit connection and adapter's white insulation separating from the magnetic end of the MagSafe connector. Following the release of a Knowledge Base article, a class-action lawsuit was filed on May 1, 2009, in the US District Court for the Northern District of California's San Jose office, alleging that the MagSafe power adapter is prone to frayed wires and overheating, and as such represents a fire hazard.
Apple released a firmware update in October 2010 that it claims resolves this issue. However, the installer for the firmware update will not run on certain older MacBooks, which means that the firmware can not be updated. This, in turn, means that it is not possible to use the new MagSafe power adapter with these MacBooks. However, as of 2023, Apple still sells power adapters for both MagSafe 1 and MagSafe 2.
In 2011, Apple posted a support document about the strain-relief problems with the MPM-1 ("T")-style MagSafe power cables, and issued settlement offer for buyers of Apple 60 W or 85 W MagSafe MPM-1 adapter within the first three years of purchase.
References
External links
Part of the Ars Technica review of the MacBook Pro is dedicated to the MagSafe connector.
Apple Inc. hardware
DC power connectors
Products introduced in 2006