GLOSSARY of Printed Circuits

Index to terms on this page:

MAC address   Manhattan algorithm  
Manhattan length   male   manufacturing zone  
master aperture list   MBGA   MCR   MCU   MDI   MDI vs. MDI-X   MES   MECL   MELF   MEMS   MES  
mezzanine cards   M field   MIC  
micro ball grid array   micro BGA   micro via   mil   MISO   MLC   MLCC   MLF   MLP   MMC   MMS   mode  
molded inductors   monolithic  
monolithic integrated circuit   MRP   mSAP   MSB   MSL   MSOP   MTBF   MTF   M2M   mullite   multimeter  

MAC address — A media access control address (MAC address) is a unique identifier assigned to a network interface controller (NIC) for use as a network address in communications within a network segment. This use is common in most IEEE 802 networking technologies, including Ethernet, Wi-Fi, and Bluetooth. Within the Open Systems Interconnection (OSI) network model, MAC addresses are used in the medium access control protocol sublayer of the data link layer. As typically represented, MAC addresses are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or without a separator.

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Manhattan algorithm — An algorithm to determine a cross street for an avenue address in Midtown Manhattan New York City, or for the length of a trip from one address in Manhattan to another. If you know the building addresses for where you are and where you want to go in Manhattan, you can call a cab company and find out what it will cost you. An algorithm is used to get the answer, because in Manhattan the street and avenue numbers do not necessarily correspond intuitively to the building numbers. To see an example of the Manhattan algorithm as an intersection locator, go to http://www.ny.com/locator/. What does this have to do with PCB design? The Manhattan algorithm has many variations and uses in various branches of mathematics, including the mathematics of auto-routers.  See also Manhattan length.

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Manhattan length — The length of the two sides of a right triangle as a distance between two points, as opposed to the hypotenuse.. (Derived from the Manhattan algorithm for determining the length of a taxicab trip following streets and avenues on the island of Manhattan, NY.)  Routing of traces in orthagonal patterns in a PCB design, or in a semiconductor chip, follows the same pattern as streets and avenues in a city.  The minimum distance between two component leads, or two nodes on a chip, when routing on 90 degrees is the Manhattan length .

 Advanced PCB auto-routers permit specification of maximum length of classes of nets as a percentage of Manhattan length . For example, one could specify clocks as 120% and random nets as 160% of Manhattan length . (This percentage, expressed as a ratio, becomes the "Manhattan coefficient", ie. a Manhattan coefficient of 1.2 means the routed length is 120% of the Manhatten length .) Specifying such limits on the auto-router prevents long and circuitous routes.

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male — politically incorrect modifier which denotes a pin-type connector terminal.

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manufacturing zone — See courtyard manufacturing zone

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master aperture list — 1. An aperture list which is used for every PCB designed by a PCB design service bureau or department.  If a new design requires one or more new apertures, they are added to the list, either at the end or in some previously unused positions set aside for that purpose. The previously used aperture positions are never edited to change their parameters. Thus the updated list can still be used as a master for any previous PCB's designed. This type of master aperture list became possible only with the advent of laser photoplotters , which can have upwards of 1000 positions if need be.  2. Any aperture list which is used with two or more PCB's would be called the master aperture list for that set of PCBs.

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MBGA — Micro Ball Grid Array A BGA with ball pitch of 0.5 mm or less.

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MCR — Molded Carrier Ring. A type of fine-pitch chip package named for the method of supporting and protecting the leads. The leads are left straight; the ends of the leads are embedded in a strip of plastic, which is the Molded Carrier Ring. Just before assembly (placing on a PCB for soldering), the MCR is cut off and the leads are formed. In this way, the delicate leads are protected against damage in handling until just before assembly.

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MCU — MicroController Unit.

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MDI — A Medium Dependent Interface (MDI) describes the interface (both physical and electrical) in a computer network from a physical layer implementation to the physical medium used to carry the transmission. Ethernet over twisted pair also defines a medium dependent interface crossover (MDI-X) interface. Auto MDI-X ports on newer network interfaces detect if the connection would require a crossover, and automatically chooses the MDI or MDI-X configuration to properly match the other end of the link.

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MDI vs. MDI-X — The terminology generally refers to variants of the Ethernet over twisted pair technology that use a female 8P8C port connection on a computer, or other network device.

The X refers to the fact that transmit wires on an MDI device must be connected to receive wires on an MDI-X device. Straight through cables connect pins 1 and 2 (transmit) on an MDI device to pins 1 and 2 (receive) on an MDI-X device. Similarly pins 3 and 6 are receive on an MDI device and transmit on an MDI-X device. The general convention was for network hubs and switches to use the MDI-X configuration, while all other nodes such as personal computers, workstations, servers and routers used an MDI interface. Some routers and other devices had an uplink/normal switch to go back and forth between MDI and MDI-X on a specific port.
Netgear Model EN104tp EN106tp EN108tp Ethernet Hub Installation Guide Bay Networks. August 3, 1998. p. 5. Retrieved June 18, 2011. br />
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MECL — (MECK-əl)   Pronunciation Key  noun  [Electronics] Motorola ECL. Families of emitter coupled logic originally from Motorola. MECL needed an external bias supply in addition to the two voltage rails. Very obsolete technology. [http://www.plexoft.com/SBF/M02.html#MECL]

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MELF — Metal ELectrical Face - A surface mount discrete part, usually a diode, that is barrel shaped, or cylindrical. The ends of the "barrel" are capped with metal, the "metal electrical face." The "barrel" is laid on its side, the metal ends upon landing pads, and the part is soldered that way. The two most common sizes are MLL34 and MLL41, which are roughly MELF versions of a DO-35 and DO-41 respectively.

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MEMS — Micro-Electro-Mechanical Systems. A technology that in its most general form can be defined as miniaturized mechanical and electro-mechanical elements (i.e., devices and structures) that are made using the techniques of microfabrication. What is MEMS Technology?

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MES — manufacturing execution system, a Sanminia term for connecting its equipment to the cloud (to a virtual factory) enabling real time, M2M (machine-to-machine) communication for their manufacturing equipment, even though many of the machines and factories are in separate locations, globally distributed. These virtual factories replicate physical production flow.
Cloud-based MES is a key element in Sanmina's Industry 4.0 initiative (i4.0).Validation rules and a forced quality framework ensure that each product is manufactured in accordance with the defined bill of materials, approved manufacturer list and product specifications. In the second example the availability of real-time data from equipment and scanners in multiple factories allows more efficient management of global supply chains.

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mezzanine cards — See PCI mezzanine card .

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M field — Magnetic field.

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MIC — Monolithic Integrated Circuit.

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micro ball grid array — A fine pitch ball grid array. Fine pitch for BGAs is anything equal to or less than 0.5 mm [19.7 mil ]. Breakout will usually involve blind and buried vias with blind vias in the ball lands. Some low-ball-count micro BGAs can get by with controlled-depth blind microvias under the BGA and without needing buried micro vias.

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micro-BGA or micro BGA — See micro Ball Grid Array.

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micro via — See blind via and buried via.

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mil — One thousandth of an inch [0.0254 mm] [From shortening of milli-inch, which means one-thousandth of an inch.]

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MISO —

1. Master In Slave Out (Serial Peripheral Interface)
2. Multiple Inputs, Single Output (electrical systems analysis).

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MLC —

1. Multi-Layer Ceramic.
2. Multi-Level Cell (see EFD)

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MLCC — Multilayer Ceramic Capacitor

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MLF — Micro Lead-Frame. The quad version of this type of package is FQFP-N, aka QFN. See also LLP.

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MLP — Micro Leadframe Package (semiconductor packaging). The quad version of this type of package is FQFP-N, aka QFN. See also LLP.

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MMC — Maximum Material(s) Condition (geometric dimensioning and tolerancing) "Component holes are usually

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plated and the MMC of the hole (when the plated-through hole is at its minimum size) must accommodate the lead diameter of the through-hole component."

MMS — Multimedia Messaging Service (MMS) is a standard way to send messages that include multimedia content to and from a mobile phone over a cellular network. The MMS standard extends the core SMS (Short Message Service) capability, allowing the exchange of text messages greater than 160 characters in length.

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mode — -- One of several types of electronic wave oscillation that may be sustained in a given resonant system. Each type of vibration is designated an a particular mode and has its own particular electric-field and magnetic-field configurations. [Graf, Rudolf F. Modern Dictionary of Electronics. Newnes, 1999]

Terms that use this meaning for mode include "odd-mode impedance," "common mode," "single-ended mode," "differential mode" and "common mode signal."

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molded inductors — The "molded" type value was originally intended to specifically reference a patented construction method, in which an inductor's core is formed around its windings using powder processes, rather than the windings being formed around a core as in traditional construction methods. Such an approach can provide performance advantages relative to traditional construction methods, and devices produced in this way are classified as being of "molded" type.

Not all devices currently categorized as "molded" however, are produced in this fashion, as many products undergo a molding process using plastic, ceramic, or other materials simply to encapsulate the product, rather than to form an active part of the device. Given that most such devices are formed by wrapping wire around a core rather than one of the other methods, "wirewound" would likely be the more correct type value for such products. Fixed Inductors-Molded

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monolithic — 1.  Existing as one large, undifferentiated whole.   2.  (of an integrated circuit or its elements) built upon or formed within a single slice of silicon substrate.

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monolithic integrated circuit — Abbreviated MIC.

1. An integrated circuit formed upon or within a semiconductor substrate with at least one of the circuit elements formed within the substrate.
2. A complete electronic circuit or IC fabricated as an inseparable assembly of circuit elements in a single small structure. It cannot be divided without permanently destroying its intended electronic function.  
3. [Graf, Rudolf F. Modern Dictionary of Electronics. Newnes, 1999] Most ICs are monolithic, but some are hybrid circuits.

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MRP — Manufacturing Requirements Planning

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mSAP — semi-additive fabrication process. An alternative to the subtractive process is the mSAP (semi-additive fabrication process), which enables a transition to much finer circuit geometries.

With mSAP, a much thinner copper layer is coated onto the laminate, and plated in the areas where the resist is not applied—thus, the "additive" nature of the process. The thin copper remaining in the spaces between conductors is then etched away. Whereas trace geometries are chemically defined during subtractive processes, mSAP allows trace geometries to be defined via photolithography. The traces are therefore formed with much greater precision, in straight vertical lines, yielding a rectangular-shaped cross-section that maximizes circuit density and enables accurate impedance control with lower signal loss.

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MSB — Most Significant bit. Eg. in a 32-bit bus, the LMSBs would be signals 16-31. Cf. LSB.

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MSL — Moisture Sensitivity Level Eg."Case TEPBGA-2 is RoHS compliant, lead-free MSL (moisture sensitivity level) 3." [IMX53AEC.pdf - NXP (Freescale Semiconductor) 5-2015]

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MSOP — (IM-sop)  Pronunciation Key  noun  [PCB Components] Micro (or Mini) Small Outline Package. This is a surface-mount package with a dual in-line arrangement of pins.
   Maxim calls this a uMax or uSop (where the u stands for the Greek letter "Mu"). These are similar to TSSOP's, but have narrower bodies.
   The acronym does not define the lead pitch. Some MSOPs have 0.5mm and others have 0.65mm pitch.
   The acronym is insufficient to define the part—you MUST consult the spec sheet's mechanical drawing in order to build an accurate footprint. Followed by a number, with or without an intervening hyphen, it roughly defines the package (somtimes it is used with the number followed by the acronym. For example, MSOP8, MSOP-8 or 8MSOP is an 8-lead device.



The picture shows a simple 3D body MSOP8_SOP65P490X110-8N (My library part naming scheme starts with a commonly-used acronym followed by an IPC naming convention. This way, I can search my footprint library on MSOP to find the footprint. The IPC-7351B naming convention doesn't include an intuitive string to search on.)

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MTBF — Mean Time Between Failures, a reliability prediction parameter.

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MTF — Multi-layer Thin Film.

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M2M — [Communications Technology] and [Industry 4.0] machine-to-machine communication.

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mullite — [Ceramics] A substrate compound of alumina and silica (3Al ₂ O ₃ •2SiO ₂ ).

Because of its low dielectric constant, mullite has now emerged as a substrate material in high-performance packaging applications. [Source: ABSTRACT - Mullite for Structural, Electronic, and Optical Applications]
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multimeter — A portable test instrument which can be used to measure voltage, current, and resistance.

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