|M2M||Machine-to-machine or machine-to-mobile communications, via wireless technologies such as cell phone network technologies, WLAN, Bluetooth, and RFID (radio frequency identification). Applications include automatic meter reading, fleet management, vending, monitoring and control, security and alarms, and telemedicine.|
|mA||Milliampere, or milliamp: 1/1000 of an Ampere. Ampere is the basic unit for measuring electrical current.
What is a Milliampere Equal To?The “Ampere”, usually abbreviated as “Amp” in spoken language, is the SI unit of electrical current and has the written symbol A. Electronic components usually use currents that are less than 1 Amp. Engineers use engineering notation (a subset of scientific notation) to avoid using fractions. Instead of using terms like 0.5 Amps or 0.01 Amps, it is more convenient to express small currents as multiples of “milliAmps”.
One milliAmp is equivalent is one thousandth of an Amp. For example, 0.1 Amps is equivalent to 100 milliAmps and 0.01 Amps is 10 milliAmps. While the term “milliAmp” is used in spoken communication, it is abbreviated as mA in writing. A Light Emitting Diode or LED (Figure 1) typically used to indicate if a piece of equipment is switched on or in standby will normally use between 10 and 30 milliAmps.
Figure 1. LED standby indicator
What is a microAmpere?A microAmpere (usually abbreviated as microAmp in spoken language) is one thousandth of a milliAmp or 1 millionth of an Amp. 1 microAmp is abbreviated in writing as 1 µA. The symbol “µ” (pronounced “mew”) is from the Greek Alphabet. As electronic components have shrunk in size, the amount of current they use has also got smaller, even less than 1 mA. Currents that are smaller than 1mA are usually referred to in multiples of microAmps. For example, 0.1 mA is equivalent to 100 µA. Electronic components that use currents less than 1mA are often referred to as microelectronic components or devices. An example would be a single transistor on a silicon chip. The symbol for a transistor is shown in Figure 2.
Figure 2. Transistor Symbol
What Does Milliampere Stand For?The term milliAmp is commonly used when specifying the capacity of a battery. For example, the capacity of a mobile phone battery (Figure 3) might be 3000 milliAmp – hours (written as 3000 mAh). This means the battery can supply 3000 mA for 1 hour or 6000 mA for 30 minutes or 1000mA for three hours etc. In other words, the more current that is used by the phone, the shorter the length of time the battery will last.
Figure 3. 3000mAh Mobile Phone Battery
What is the Meaning of mA in Electricity?Electricity companies charge customers for electricity by the amount of current they use called “units”. One unit of electricity is 1 kilowatt-hour (in the U.S, this equates to approximately 10 Amps per hour). The number of units used is recorded on an electricity meter (Figure 4). Readings are made, usually monthly or bimonthly, and consumers are then billed for their usage.
Figure 4. Electricity Meter
|MAC||See MAC Address|
|MAC Address||Media Access Control Address (maca, MAC): A hardware address that uniquely identifies each node of a network, as in IEEE-802 (Ethernet) networks. The MAC layer interfaces directly with the network medium.|
|maca||See MAC Address|
|Manchester Data Encoding||Manchester encoding is a form of binary phase-shift keying (BPSK) that has gained wide acceptance as a modulation scheme for low-cost radio-frequency (RF) transmission of digital data. Its key characteristic is that it encodes data in a way that insures there will never be long strings of continuous zeros or ones. The guaranteed transitions means that the clock can be derived from the transmitted data, allowing the link to function with variable signal strengths from transmitters with imprecise, low-cost, data-rate clocks.
Details: See the application note, Manchester Data Encoding for Radio Communications.
|Manchester Encoding||See Manchester Data Encoding|
|manganese dioxide||See Lithium batteries|
|manganese lithium||See Lithium batteries|
|MAP||Manifold absolute pressure|
|Margining||Margining is a test procedure that determines the "safety margin." A parameter is varied to determine the device's sensitivity or ability to perform given a range of inputs. A large number of parts can be characterized to determine a safe range for the specification, to guarantee performance and yield.|
|Master Out Slave In||See MOSI|
|Max. DNL (LSB)||Maximum differential nonlinearly expressed in least significant bit(s).|
|Max. Hold Step (MV)||When switching between sample mode and hold mode, charge injection from stray capacitance causes the maximum voltage of the hold capacitor to change.|
|Max. INL as percent FSR||"Max. INL (±%FSR)" is the maximum integral nonlinearity, expressed as a percentage of full-scale range.|
|MaxBass||See Bass Boost|
Make-before-break: In a switching device, a configuration in which the new connection path is established before the previous contacts are opened. This prevents the switched path from ever seeing an open circuit.
Applies to mechanical systems (e.g. that use relays or manual switches) and to solid-state analog multiplexers and switches.
Learn More: Switches and Multiplexers
|MBC||Main booster converter|
MCM is generally used for very large-diameter wire. Most wire uses AWG.
|Mcps||1. Megacycles per second (obsolete): Megahertz
2. Megachips per Second (Mcps): In a Direct-Sequence Spread Spectrum signal, a "chip" is an encoding element. Mcps is a measure of the speed at which chips can be generated by a circuit.
|MDAC||Multiplying digital-to-analog converter|
|MEC||See Micro Energy Cell|
|Media Access Control Address||See MAC Address|
|Media Independent Interface||A parallel digital bus used for 10Mbps and 100Mbps Ethernet.|
|MegaBaud||RS-232 logic-level compatible data rates that are 1Mbps or higher.|
|Megachips per Second||See Mcps|
|Megacycles per Second||See Mcps|
|MEMS||Acronym for "Micro Electronic Mechanical Systems," or microelectromechanical systems: Systems that combine mechanical and electrical components and are fabricated using semiconductor fabrication techniques. Common examples are pressure and acceleration sensors which combine the sensor and amplification or conditioning circuitry. Other applications include switches, valves, and waveguides.|
|MESFET||A Metal-Semiconductor Field-Effect-Transistor uses a metal-semiconductor (Schottky) junction to create the conductive channel, rather than using a p-n junction as a JFET does; or a metal-oxide-semiconductor layer as a MOSFET uses.|
|Metal Oxide Varistor||A Metal Oxide Varistor (MOV, or surge-suppressor) is a discrete electronic component that diverts excessive voltage to the ground and/or neutral lines.|
|metal whiskers||See Tin Whiskers|
|Metal-Semiconductor Field-Effect-Transistor||See MESFET|
|MFSK||Multiple frequency-shift keying|
|MHz||Megahertz (MHz): Measurement of frequency -- million cycles per second.|
|Micro Energy Cell||A Micro Energy Cell (MEC) is a small, rechargeable, very long life, energy storage device used in energy harvesting applications.
An example is the THINERGY® MEC from Infinite Power Solutions.
|Microelectromechanical systems||See MEMS|
|MicroLAN||A 1-Wire network. A low-cost network in which PCs or microcontrollers communicate digitally over twisted-pair cable using 1-Wire components.|
|MicroMonitor™||A device that monitors three conditions vital to processor-controlled systems: power supply, software execution, and external override.|
|Microprocessor Supervisor||A device that monitors a host microprocessor or microcontroller's supply voltage and, in some cases, its activity. It monitors for a fault condition and takes appropriate action, usually issuing a reset to the microprocessor.|
|MII||See Media Independent Interface|
|MIMO||A Multiple Input, Multiple Output (MIMO) system has multiple antennas and multiple radios. It takes advantage of multipath effects, where a transmitted signal arrives at the receiver through a number of different paths. Each path can have a different time delay, and the result is that multiple instances of a single transmitted symbol arrive at the receiver at different times.
Usually multipath is a source of interference, but MIMO systems use the fact that data will arrive at the receiver at different times through different paths to improve the quality of the data link. For example, rather than relying on a single antenna path to receive an entire message, the message can be pieced together based on fragments received at the various antennas. This can act to either increase the data rate at a given range, or increase system range for a given data rate.
MIMO is used in the implementation of the 802.11n standard.
|Min LOS Sens.||The minimum sensitivity attainable with a programmable loss-of-signal feature.|
|Min Stable Closed Loop Gain||The minimum closed-loop gain for which the amplifier is stable.|
|MISI||Master-in, slave-out isolated input|
|MISO||Master-in, slave-out isolated output|
Mixed-signal ICs are integrated circuits that contain both analog and digital circuitry on one chip. An analog signal is a continuous time-varying signal, and a digital signal is a noncontinuous signal that takes on only a finite number of values. Mixed signal ICs make use of both of these types of signals. Mixed-signal ICs are used in a wide variety of applications and application-specific integrated circuits (ASICs).
As an example, a building block of analog circuit design is the op amp, which is a high-gain amplifier. An op amp can take a continuous signal and output another, higher-valued, continuous signal. An op amp can also be used to make a comparator, which is a circuit that compares two input voltages and outputs a binary signal indicating which is larger. Since the output of the comparator is digital, this is an example of a mixed-signal circuit.
Where analog signals are continuous, digital signals are discrete, meaning that they take on a finite number of values. An example is a square wave, where a signal alternates between values in steps, ideally instantaneously. Another example is a binary signal, which can have two possible values (such as 0/1 or on/off) and is used in logic gates such as AND/NAND gates or in D flip flops.
ADCs and DACs
The two clearest examples of mixed-signal ICs are analog to digital converters (ADCs) and digital to analog converters (DACs). Since these convert analog to digital or digital to analog, they must contain circuitry for both.
|ML||See Lithium batteries|
What is a Modulator?
A modulator is an electronic circuit that superimposes a low-frequency (information) signal onto a high-frequency (carrier) signal for the purpose of wireless transmission. The reason for this is that higher frequency signals can be received using shorter aerials, which are more practical than longer ones. The information signal can be either analog or digital.
The modulator circuit superimposes the information signal onto the carrier signal by modifying one of the properties of the carrier, i.e., amplitude, frequency, or phase.
The following table summarizes the main modulation types for each type of information signal.
Once the transmitted signal has been detected and received, a demodulator circuit is then used to recover the information signal from the carrier.
Learn More: I/Q Modulators and Demodulators
|Monotonic||A sequence increases monotonically if for every n, Pn + 1 is greater than or equal to Pn. Similarly, a sequence decreases monotonically if for every n, Pn + 1 is less than or equal to Pn.
In plain language, the value rises and never falls; or it falls and never rises.
|MOSFET||Metal-oxide semiconductor field-effect transistor; metal-oxide silicon field-effect transmitter.
In a MOSFET, the conductive channel between the drain and source contacts is controlled by a metal gate separated from the channel by a very thin insulating layer of oxide. The gate voltage establishes a field that allows or blocks current flow.
Compare to a JFET, in which a p-n junction controls the channel; or a MESFET, which uses a metal-semiconductor (Schottky) junction.
|MOSI||Master Out Slave In: One of the four Serial Peripheral Interface (SPI) pins.|
|MOV||See Metal Oxide Varistor|
|MQFP||Metric quad flat pack|
|MSA||Measurement Systems Analysis is a method for ensuring product test measurements are reliable, robust, and of good statistical merit.|
|MSB||Most-significant bit. In a binary number, the MSB is the most weighted bit in the number. Typically, binary numbers are written with the MSB in the left-most position; the LSB is the furthest-right bit.|
Megasamples per second: A measure of speed in digitizing systems, samples per second dictates the maximum frequencies that can be accurately captured.
|MTIMD||Multitone intermodulation distortion|
|MTPR||Multitone power ratio|
|Multi-Chip Module||See MCM|
|Multipath||In radio transmission, multipath refers to the simultaneous reception of two copies of the signal, that arrive via separate paths with different delays.
A common example is when a signal bounces off a building or other object and is received along with the direct (unbounced) signal. In television reception, this causes "ghosting" -- one sees a faded echo on the screen horizontally displaced from the main image.
Another common example is in radio (especially AM radio), where the signal bounces off the ionosphere and one receives that delayed signal along with the directly transmitted signal.
Usually, multipath is an undesired effect but in MIMO systems, separate antennas deliberately send replicas and sophisticated receivers piece together the fragments to improve performance.
|multipath interference||See Multipath|
|Multiple Input-Multiple Output||See MIMO|
|Multiplex||1. Combining two signals (which can be analog or a digital stream) into one in such a way that they can later be separated. Examples are OFDM; standard FM stereo broadcast (in which left and right are multiplexed onto one baseband signal); standard television in which video and several audio signals shared the channel; and time-division multiplexing which gives each signal a separate time-slice.
2. An array of analog switches, usually on a single CMOS chip, that allows one input signal to be routed to any of several output lines, depending on the value of a set of digital control lines.
A multiplexer can also be used in the opposite direction, allowing the array to connect one of several input lines to the output, depending on the control lines.
Several of these can be implemented on one chip to make a multi-channel version.
Maxim makes hundreds of these parts. See the Analog Switch and Multiplexer Product Line page.
|Murphy's Law||Anything that can go wrong, will.|
|mutual conductance||See Transconductance Amplifier|
|mV||A millivolt (mV) is 1/1000 of a volt.|
|MxTNI||MxTNI™ (Maxim Tiny Network Interface, formerly called TINI) is Maxim's trademark for the industry's smallest web server. The MxTNI platform consists of a microcontroller that includes the facilities necessary to connect to the Internet. The platform is a combination of broad based I/O, a full TCP/IP stack and an extensible Java runtime environment that simplifies development of network-connected equipment.|