Glossary - All Terms and Definitions Listed Alphabetically

More info:

• 1-Wire Memory Products
• 1-Wire Interface Solutions
• 1-Wire SW Tools

Sound-pressure levels derived using A-weighting are denoted by "dBA," or A-weighted dB levels.

The frequencies that shift are sometimes called "folded" frequencies because a spectral plot looks like it was folded to superimpose the higher frequency components over the sub-Nyquist portion of the band.

Also see:

• Application Note/Tutorial: Filter Basics: Anti-Aliasing
• The Basics of Anti-Aliasing: Using Switched-Capacitor Filters
• Mathematical Basics of Band-Limited Sampling and Aliasing
• Folded-Frequency Calculator

2. Amplifier

The symbol I is used for current in equations and A is the abbreviation for ampere.

For example: A microphone produces a current that is proportional to sound pressure. Various stages amplify, process, modulate, etc. Ultimately, a varying voltage is presented to a speaker which converts it back to sound waves.

By contrast, a digital system handles a signal as a stream of numbers.

For example, an analog switch can turn an audio signal on or off based on a MUTE signal; or analog switches could send one of two signals to a headphone amplifier.

Most commonly implemented using CMOS technology integrated circuits. Maxim makes hundreds of examples. See the Analog Switch and Multiplexer Product Line page.

Also see What is a Transmission Gate (Analog Switch)?.

Also see:

• Application Note/Tutorial: Filter Basics: Anti-Aliasing
• The Basics of Anti-Aliasing: Using Switched-Capacitor Filters

See: Maxim ASIC services.

2. American Wire Gauge: A measure of wire thickness (which also dictates cross-sectional area, and for a given material, ampacity). Example: 24 AWG wire has a nominal diameter of 0.0201 inch or 0.511 mm. Also called the Brown and Sharpe Wire Gauge.

Note that steel wire is measured by a different gauge. AWG only applies to wire used to conduct electricity.

Example: An AM broadcast radio channel in the US has a bandwidth of 10kHz, meaning that it occupies a 10kHz-wide band, such as the frequencies from 760kHz to 770kHz.

2. The amount of data a digital channel or line can handle, expressed in bits per second (bps), kilobits per second (kbps), baud, or a similar measure.

A femto base station is a smaller, personal base station which might cover a home or building and connect via a DSL Internet connection.

Contrast to the other main transistor type, the FET, in which the ouput current is controlled by input voltage (rather than by input current).

Applies to mechanical systems (e.g. that use relays or manual switches) and to solid-state analog multiplexers and switches.

This can double the voltage swing at the speaker, compared to a speaker that is connected to ground. The ground-tied speaker can have a swing from zero to the amplifier's supply voltage. A BTL-driven speaker can see twice this swing because the amplifier can drive either the + terminal of the speaker or the — terminal, effectively doubling the voltage swing.

Since twice the voltage means four times the power, this is a major improvement, especially in applications where battery size dictates a lower supply voltage — e.g. automotive or handheld applications.

This technique is used, for example, to provide fifty CATV channels on one coaxial cable; or to provide Internet access over cable TV; or to add DSL to a voice-grade telephone line.

A common technique is frequency-division. Each channel is modulated to a different frequency band and combined in the transmission medium. It is demodulated to its original frequency at the receiving end. Channels are separated by guardbands (empty spaces) to ensure that each channel will not interfere with its neighboring channels.

Note: A customer asked the origin of the term and no one seems to know! A buck regulator is a step-down regulator, as opposed to boost. We think it's an American term — in England it was always "step-down."

Buck means to resist or reduce (as in "buck the trend"), and hence was used to denote a step-down. Conveniently, it alliterates with the opposite, a boost regulator.

2) The maximum short-term throughput which a device is capable of transferring data.

Often misspelled "buss."

2. Also see Y/C

Maxim offers both regulated and non-regulated charge pumps, as well as ICs with on-board charge pumps to boost internal voltages.

See: DC-DC Converter Tutorial

2. Encoding element, in Direct-Sequence Spread Spectrum systems.

This is achieved by biasing both transistors so they conduct when the signal is close to zero (the point where class B amplifiers introduce non-linearities). The transistors transition to class B operation for large excursions.

So, for small signals both transistors are active, acting like a class A amplifier. For large signal excursions, only one transistor is active for each half of the waveform, acting like a class B amplifier.

Class B amplifiers are much more efficient than class A amplifiers, but have high distortion due to the crossover point when the two transistors transition from on to off.

Class C amps are very efficient because the transistors are off most of the time and when they are on, they are in full conduction. They deliver high distortion and are often used in RF circuits, where tuning circuits restore some of the original signal and reduce distortion. They are also used in low-fidelity applications where the distortion is not important, such as a siren speaker driver.

Class D amplifiers are highly efficient (often up to 90% or higher) since the output transistors are either fully turned on or off during operation. This completely eliminates the use of the linear region of the transistor which is responsible for the inefficiency of other amplifier types. Modern Class D amplifiers achieve fidelity comparable to class AB.

Class G amplifiers are more efficient than class AB amplifiers since they use the maximum supply voltage only when required, while a class AB amplifier always uses the maximum supply voltage.

Class H amplifiers are generally more complex than other designs, with extra control circuitry required to predict and control the supply voltage.

• powered up (power applied)
• powered down (power removed)
• brought out of shutdown (power applied previously)
• forced into shutdown (power still applied)

For more information and illustrations, see:

• "Jitter Overview" in HFAN-04.3.0: Jitter Specifications Made Easy; and
• An Introduction to Jitter in Communications Systems.

See the tutorial, Understanding Common-Mode Signals.

Examples: In NTSC television, a 3.579545MHz color subcarrier is quadrature-modulated by two color-difference signals and added to the luminance signal. The PAL television standard uses a subcarrier frequency of 4.43362MHz.

See: Video Basics

In an ideal differential amp, the common-mode element is cancelled out, since the differential (+ and -) inputs should subtract out the identical components. A measurement of the actual ability to do this is called the Common Mode Rejection Ratio, or CMRR.

See the tutorial, Understanding Common-Mode Signals.

A signal is passed through a non-linear transformation prior to transmission. A reverse of this transformation occurs at reception. The transformation is such that quiet portions are boosted and loud portions reduced. Noise is reduced because the quiet signals are louder, compared to the noise in the transmission channel.

Used in digital, PCM, transmissions as well as analog applications. Dolby is a common example of a compander-based noise reduction system.

When described that way, the comparator resembles a 1-bit ADC.

A simple comparator can be achieved using an op amp without negative feedback. Its high voltage gain enables it to resolve very small differences in input voltage. But op amps used this way are generally slower than comparators and lack special features, such as hysteresis and internal references.

Application Note 886: Selecting the Right Comparator goes into more details on how comparators work, their specifications, common comparator features, and how to select a comparator that best fits your needs.

It is usually achieved by an SCR or other silicon device, or by a mechanical shorting device.

Probably named for the concept of using a big metal bar to mechanically provide the short circuit, as might be used done in a high-current application; or from the appearance of a crowbar circuit's I-V curve.

See: Protection and Isolation products.

An analog signal is a continuously varying voltage or current. Its digital counterpart is a stream of digital numbers, each representing the amplitude of the analog signal at a moment in time.

Also see:

• A Simple ADC Comparison Matrix
• Understanding SAR ADCs
• Understanding Flash ADCs

dB = 10 times the log of the ratio of the power of the two signals. This is equal to 20 times the ratio of their voltages, if the signals are driving equal impedances.

Decibels are also used to describe a signal level by comparing it to a reference level. The reference is usually defined as 0dB and the dB value of the signal is 10 times the log of the signal's power over that of the reference. A letter is sometimes added to signify the reference. For instance, dBm is relative to 0 dBm = 1mW.

See: DC-DC Converter Tutorial

In the most straightforward realization, a digitized sample of the waveform is stored and the values are clocked out to a D/A converter. Varying the clock rate changes the frequency. Variations in rate and changes to a gain factor can modulate the signal.

More: Switch Bounce and Other Dirty Little Secrets

For more information and illustrations, see:

• "Jitter Overview" in HFAN-04.3.0: Jitter Specifications Made Easy; and
• An Introduction to Jitter in Communications Systems.

Examples: RS-422, RS-485, professional audio signal standards (especially for microphones), the signal lines employed by Ethernet, and the standard twisted-pair analog telephone (POTS) line.

Also see the tutorial, Understanding Common-Mode Signals.

Not all signal alterations are considered distortion. For instance, a uniform delay or a linear attenuation or amplification would generally not be considered distortion.

See: High-Brightness LED Drivers

This process is reserved for package types which are especially susceptible to moisture intrusion. Maxim devices with MSL (Moisture Sensitivity Level) of 2 or higher require drypack. A part-number suffix of -D, +D, or #D at the end of the part number denotes products which ship with drypack. There is no price adder associated with drypacking products with MSL 2 or above.

See: "An Introduction to Direct-Sequence Spread-Spectrum Communications".

Each digit is encoded as the sum of two sine wave bursts, of different frequencies. The two-tone method was chosen because it can be reliably distinguished from voice and normal phone conversations are highly unlikely to falsely trigger the DTMF receiver.

DTMF was the basis for "TouchTone" (a former trademark of AT&T), the pushbutton system that replaced mechanical rotary dial telephones.

(Maxim Integrated Products, Inc. trademarked term.)

This low-frequency signal is then further divided by the main counter to the desired channel-spacing frequency which is then fed to the phase detector to form the closed feedback loop in frequency synthesizers.

Often, the computer is relatively invisible to the user, without obvious applications, files, or operating systems. Examples of products with invisible embedded systems are the controller that runs a microwave oven or the engine control system of a modern automobile.

See: EMI Reduction Solutions page.

See the following application notes that describe how ESD is generated, how it damages electronic systems, human body and machine models for testing, IEC compliance levels, and design approaches.

• App note: Maxim Leads the Way in ESD Protection
• App note: ESD Protection for I/O Ports
• App note: Switch Bounce and Other Dirty Little Secrets

See: ESD Overview.

A capacitor can be modeled as an ideal capacitor in series with a resistor and an inductor. The resistor's value is the ESR.

EVKIT: Part number suffix used for Maxim Evaluation Kits.

Dallas Semiconductor, now owned by Maxim, used the term "development kit."

See the list of Maxim Evaluation Kits and EVKit software.

EVSYS: Suffix used for Maxim Evaluation System part numbers.

2. f in lower case is the standard abbreviation for femto, a metric prefix for 10 to the -15.

A femto base station benefits the service provider because it offloads cell tower traffic. Subscribers benefit from superior signal strength, due to the proximity of the unit -- especially where a cellular signal is weak or not available.

Femto base stations augment the normal network and replicates the usual telecommunications infrastructure. Connection to the cell phone network is provided by VoIP over the Internet.

More on femto base stations and information on Maxim's femto base station chipsets.

There are three varieties: The JFET (Junction Field-Effect Transistor); the MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor); and the MESFET (Metal-Semiconductor Field-Effect Transistor).

The FET is one of two major kinds of transistor, the other being the Bipolar Junction Transistor.

Bin = f_SAMPLE/N_RECORD = 1/(N_RECORD × Δt_SAMPLE)

Contrast with FTTN (fiber-to-the-node) which uses fiber up to a node outside the home and uses copper to bring the data into the home.

There are two technologies for delivering broadband: Fiber-to-the-node (FTTN) uses fiber to bring data to a node and uses copper to bring the data into the home. Fiber-to-the-home (FTTH) brings fiber all the way into the home.

Gain error is usually expressed in LSB or as a percent of full-scale range. Gain error can be calibrated out with hardware or in software. Gain error is the full-scale error minus the offset error.

See: Application Note 641: ADC and DAC Glossary

Most commonly applied to make a light-emitting device, such as a display, match the human eye's brightness curve. In other terms: A gamma correction function can be used to alter the luminance (light intensity) of a display such that its brightness (the human-perceived values) looks correct.

2. A basic logic element (e.g. AND, OR, NOT, NAND, NOR, XOR, etc.).

Bluetooth uses GFSK.

See: High-Brightness LED Drivers and Solutions

See the following application notes that describe how ESD is generated, how it damages electronic systems, human body and machine models for testing, IEC compliance levels, and design approaches.

• App note: Maxim Leads the Way in ESD Protection
• App note: ESD Protection for I/O Ports

See: Maxim Solutions for HVAC designers.

Abbreviated from "in-phase/quadrature-phase" which refers to the two carrier signals' phase relationship.

2. I_Q (Q should be subscripted but sometimes printed as "IQ" without subscripting): Quiescent current: The current consumed when a circuit is in a quiet state, driving no load and if appropriate, with its inputs not cycling.

3. Intelligence quotient, a measure in which electrical engineers invariably excel.

SMBus is electrically similar — see Comparing the I2C Bus to the SMBus.

See also: I²C Data Converters, and do a site search for I2C to find other I2C articles and products.

2. Internally Connected

This variation in PWM (pulse-width modulation) combines the efficiency at low loads afforded by PFM (Pulse-Frequency Modulation) with PWM's efficiency and low-noise characteristics at higher loads. At light loads the circuit skips pulses as necessary (acting like a PFM circuit). At higher loads it acts like PWM. The net result is the maximum efficiency over the widest possible load range.

Learn more: "DC-DC Converter Tutorial" (see the paragraphs around Figure 14).

2. Commonly used to refer to one of the 13 power connectors described by specification IEC 60320. Most commonly refers to the C13 and C14 connectors used by most computers and many AC-powered electronic devices to connect the AC power.

3. Integrated electronic component.

For DC systems, impedance and resistance are the same, defined as the voltage across an element divided by the current (R = V/I).

In AC systems, the "reactance" enters the equation due to the frequency-dependent contributions of capacitance and inductance. Impedance in an AC system is still measured in ohms and represented by the equation Z = V/I, but V and I are frequency-dependent.

See also: iButton Certifications.

If we let the voltage present on the "-" input equal V1, and the voltage on the "+" input equal V2, then the common mode voltage is VCM = (V1+V2)/2.

Some op amps, for instance, will only allow the common mode voltage of a signal to come within a diode drop or so of the power supply rails. Many of Maxim's op amps will allow the common mode input voltage to go all the way to one or both supply rails. Some even allow inputs beyond the supply rails (Beyond-The-Rails™).

For example: A p-channel JFET would consist of a bar of p-type silicon with the "drain" at one end and the "source" at the other. Between these two terminals is some n-type material connected to a "gate". A positive voltage applied to the gate creates a "depletion field" which restricts current flow between the source and drain.

For more information and illustrations, see:

• "Jitter Overview" in HFAN-04.3.0: Jitter Specifications Made Easy; and
• An Introduction to Jitter in Communications Systems.

In electronics, it's the same amount of energy, in electrical units. One joule is one watt of power, applied for one second (a watt-second); or a coulomb of electrical charge raised to a potential of one volt.

In digital systems, "K" or "k" is often used to mean 2¹⁰, that is, 1024. This is not well-standardized but it's usually apparent from context. On the Maxim site, we use upper-case K to mean 1024 and lower-case k to mean 1000. This standard is applied to new documents but older documents may use "k".

2. Kelvin: Temperature scale. Zero K is defined as absolute zero. 273.15K is 0 degrees C.

Note that temperatures on the kelvin scale are called kelvins, not "degrees kelvin." The K symbol is uppercase and used without a degree symbol. The word "kelvin" in this context is not capitalized.

See: Application note 4522, "Low-Cost, Dual SCART Solution for Set-Top Boxes Also Has Optional Kanal+ Support."

2. Leaded Chip Carrier, also called PLCC or Plastic Leaded Chip Carrier: A square surface mount chip package in plastic with leads (pins) on all four sides. Example: Maxim 20-pin PLCC diagram (PDF)

In an ideal transformer, 100% of the energy is magnetically coupled from the primary to the secondary windings. Imperfect coupling causes some loss. The electrical equivalent is some self-inductance in series with the primary windings that are properly coupled. This series inductance is the "leakage inductance."

The application note, "Driving LEDs in Battery-Operated Applications: Controlling Brightness Power Efficiently" has a good explanation of how LEDs work, especially with regard to current vs. LED brightness and schemes for matching brightness when driving multiple LEDs.

Some application notes that include an LFSR:

• DC-to-DC Converter Combats EMI: Figure 2 shows how a random noise generator randomly shifts the frequency to reduce EMI.

• Pseudo-Random Number Generation Routine for the MAX765x Microprocessor

  V_OUT = k*V_IN

where k is a constant.

2. Analog; as in a "linear" circuit (as opposed to digital).

Dallas Semiconductor NV SRAM and timekeeping products use mostly BR chemistry (poly-carbonmonofluoride) primary (non-rechargeable) lithium coin cells. We use CR chemistry (manganese dioxide) primary lithium coin cells in microcontroller and touch products. Some new products use "manganese lithium" (ML) chemistry, which is chemically close to the CR, but is a secondary (rechargeable) lithium coin cell.

Lithium-ion (Li+, Li-Ion, Lion) cells are generally used as power sources for portable equipment. They are usually rechargeable. Lithium-ion and nickel-metal-hydride (NiMH) have displaced nickel-cadmium (NiCd or nicad) as the dominant rechargeable chemistry for portable applications. Maxim makes a wide range of battery management products for all these families, including chargers, fuel gauges, and smart battery components.

Lithium batteries (see link below for details) are typically coin-shaped and are used to power items such as Maxim's non-volatile static RAM (NV SRAM) and timekeeping circuits (such as real-time clocks).

2. The black and white portion of a video signal, also referred to as the "Y" component. A composite, Y/C, or Y/Pb/Pr video signal combines a luminance signal with color components.

Details: See the application note, Manchester Data Encoding for Radio Communications.

Applies to mechanical systems (e.g. that use relays or manual switches) and to solid-state analog multiplexers and switches.

2. MCM is an abbreviation for thousands of circular mils, an old measurement of wire gauge. 1 MCM = 1 kcmil = 0.5067 square milimeters. A mil is 1/1000 inch. A wire 200 mils in diameter is 40 MCM.

MCM is generally used for very large-diameter wire. Most wire uses AWG.

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.

See: "An Introduction to Direct-Sequence Spread-Spectrum Communications".

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.

In plain language, the value rises and never falls; or it falls and never rises.

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.

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.

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.

(Another distinguishing characteristic was that NTSC's dependency on accurate phase meant that it was difficult to maintain the color as the signal was transmitted and processed. Television engineers often joke that NTSC stands for "Never Twice the Same Color.")

The NTSC standard adds a color subcarrier which is quadrature-modulated by two color-difference signals and added to the luminance signal. The genius of the system is that black and white TVs ignore the color components, which are beyond the black and white signal's bandwidth.

The NTSC color subcarrier reference is 3.579545MHz. The horizontal sync rate (H) was adjusted slightly from the black and white standard's 15.750kHz such that the color subcarrier is 455/2 times H. The vertical rate is Fv = Fh x 2/525.

See: Video Basics.

In real life, sampling rate must be higher than that (because filters are not perfect). As an example, the bandwidth of a standard audio CD is a bit shy of the theoretical maximum of 22.05kHz (based on the sample rate of 44.1kHz).

Also see:

• Application Note/Tutorial: Filter Basics: Anti-Aliasing
• The Basics of Anti-Aliasing: Using Switched-Capacitor Filters

Using op amps, it's easy to make amplifiers, comparators, log amps, filters, oscillators, data converters, level translators, references, and more. Mathematical functions like addition, subtraction, multiplication, and integration can be easily accomplished.

Practical, real-world op amps have finite characteristics but in most applications, are close enough to the ideal to make a huge range of inexpensive, high-performance analog applications possible. They are the building block for analog design.

One key to op amp design is nodal analysis. Since the input impedance is infinite, the current in and out of the + and - input nodes defines the circuit's behavior.

See: Nodal Analysis of Op Amp Circuits for a good tutorial on this topic.

Also see other amplifier tutorials at: Amplifier Tutorials.

Maxim has hundreds of op amps (and other amplifiers).

It can also be done with a "wired-OR" connection in which two signals are simply wired together and either one of them can raise the level. This works when the signals are driven by a source that only pulls up or only pulls down, with a resistive load (e.g. an "open collector" output).

The crowbar short-circuits or clamps the supply line to limit the voltage, possibly triggering other forms of protection such as a fuse. See Crowbar.

The series-connected switch uses a MOSFET or transistor connected as a switch in series with the supply line. During an overvoltage condition, the OVP circuit rapidly shuts off the MOSFET and disconnects the downstream circuit.

See: Protection and Isolation products.

See: Video Basics

In contrast, a serial interface uses one wire or wire-pair or wireless channel (or one in each direction).

2. PC: Printed circuit (see: Printed Circuit Board, link below).

3. PC: Personal Computer.

PCI buses typically also support the older Industry Standard Architecture (ISA) standard.

The PCIe electrical interface is also used in a variety of other standards, most notably the ExpressCard laptop expansion card interface.

Source: Wikipedia

Note that PIV is also an abbreviation for FIPS 201 Personal Identity Verification.

See: Programmable-Gain Amplifier, Using the MAX532 DAC

Pin electronics can deliver signals, power, or precise voltages and currents, and can measure the pin's response, drive, and electrical characteristics.

See: Maxim Solutions for PLCs.

2. Powerline Communications (see link below).

Phase-locked loops are widely used in radio, telecommunications, computers and other electronic applications. They may generate stable frequencies, recover a signal from a noisy communication channel, or distribute clock timing pulses in digital logic designs such as microprocessors.

From Wikipedia.

More:

• Point-of-Load DC-DC Conversion
• POLs with integrated MOSFETs

PAE = (PRFOUT - PRFIN)/PDC = (PRFOUT - PRFIN)/(VDC*IDC)

See the application note: MAX1917 Provides Pre-Bias Soft Start for Redundant Supply

A PC board can have conductors on one side or two sides and can be multi-layer — a sandwich with many layers of conductors, each separated by insulating layers.

The most common circuit boards are made of plastic or glass-fiber and resin composites and use copper traces, but a wide variety of other materials may be used. Most PCBs are flat and rigid but flexible substrates can allow boards to fit in convoluted spaces.

Components are mounted via SMD (surface-mount) or through-hole methods (see links below).

  PSRR = (change in Vcc)/(change in Vout)

See also: Ripple rejection, which is degree of immunity from AC in the power supply.

Example: Hewlett-Packard's first commercial product, an audio oscillator, used a common light bulb as a PTC element in the feedback circuit to maintain constant output amplitude regardless of frequency.

2. A technique used to modulate the power delivered to a load.

In DC-DC switching regulators, the pulse width driving the main power switch (and hence, the duty cycle) is varied to maintain the desired output voltage. In DC motor-control applications, pulse width is used to vary motor speed.

A common application is in PAL and NTSC color television transmission. Color is encoded into two analog signals (called I and Q), which modulate quadrature color carriers.

Modems also use this approach, to increase the data bandwidth they can carry (or, more accurately, to trade bandwidth for error rate or noise immunity).

QPSK Symbol Constellation

See our QPSK tutorial: QPSK Modulation Demystified.

2. Rail-to-rail

See:

• Jitter Overview in HFAN-04.3.0: Jitter Specifications Made Easy
• An Introduction to Jitter in Communications Systems.
• Measuring Random Jitter on a Digital Sampling Oscilloscope

Examples:

• A radio receiver that detects and demodulates the signal from the airwaves
• An ultrasonic receiver that turns ultrasound signals into electrical signals
• A line receiver that receives signals from a wire or backplane
• A standard interface receiver (e.g., USB, serial, LVDS)
• A fiber optic device that translates light pulses into electrical signals

Some advantages of relays are that they provide amplification and isolation and are straightforward. They can switch difficult voltages (e.g. RF or high-powered AC) with complete isolation and no worries about level translation.

Relay disadvantages, compared to solid-state switching, include power efficiency, noise (both mechanical and electrical, including "contact bounce"), size, speed, and reliability. Analog switches are commonly used instead of relays in signal switching applications.

Driving a relay can be tricky because it's an inductive load. Special relay drivers are often used. Contact bounce is another issue. Search the Maxim site for the term "relay" to see application notes on relay driving and for relay driving products.

Maxim's ResourceSmart strategy combines tutorials, application notes, and technical articles with resource-friendly products and techniques.

Learn more...

Also see: 1-Wire RFID Alternatives.

Although more instructions must be executed for some operations, a RISC architecture can be faster, depending on the instruction mix, the design of the instruction set, and how effective the compilers and support software are in translating operations into optimized instructions.

The term "serial" interface is often used for an RS-232 interface. The usage is not quite accurate -- while RS-232 is a serial interface, there are other serial interfaces in addition to RS-232.

When it was introduced in 1987, the MAX232 rapidly became the most common way to implement RS-232 because it required only a single 5-volt supply. On-board DC-DC converters developed the odd voltages required by the official spec.

(Maxim still manufacturers the MAX232 and makes a wide range of newer products as well.)

See Selecting and Using RS-232, RS-422, and RS-485 Serial Data Standards to learn about the differences between RS-232, RS-422, and RS-485.

RS-485 and RS-422 can be configured for full-duplex or half-duplex bus systems.

See Selecting and Using RS-232, RS-422, and RS-485 Serial Data Standards to learn about the differences between RS-232, RS-422, and RS-485.

RSSI is often done in the IF stage before the IF amplifier. In zero-IF systems, it is done in the baseband signal chain, before the baseband amplifier.

RSSI output is often a DC analog level. It can also be sampled by an internal ADC and the resulting codes available directly or via peripheral or internal processor bus.

See the Real Time Clocks page for much more information.

2. Lower case s is the standard abbreviation for seconds.

2. ksps: Kilosample(s) per second (thousands of samples per second)

3. Msps: Megasamples per second (millions of samples per second)

Also see:

• A Simple ADC Comparison Matrix
• Understanding SAR ADCs
• Understanding Flash ADCs

When internal memory elements are not directly accessible from the circuit's outside pins, testing is difficult because their state is unknown. With scan design, a signal reconfigures the elements into a "scan chain" and their contents can be read and if desired, altered.

Peritel is an abbreviation for "péritélévision." Peri is a prefix that means around or surrounding — in this case, it suggests the connection between the television and its electronic environment.

2. Secure Digital, a media format for nonvolatile external memory. The successor to the "MultiMedia Card" format, or MMC, SD card memories typically operate from 3.3V supplies with modest current requirements. SD memory cards are best known as storage for digital cameras, smart phones, and other consumer electronic devices.

Also called "III-V" materials since semiconductor elements are in groups III and V of the periodic table of chemical elements.

2. An electronic device (e.g. a transistor, diode, or integrated circuit) manufactured from semiconductor materials.

Semiconductor devices control and amplify because a small voltage or current, or a physical stimulus (such as light or pressure), allows the semiconductor to pass or block electrical current. Devices can be fabricated with other capabilities such as passing electric current in only one direction, emitting light, mixing and transforming signals, etc.

By contrast, a parallel interface sends several bits at once, on separate wires.

In ADCs, Spurious-Free Dynamic Range (SFDR) is the ratio of the RMS amplitude of the carrier frequency (maximum signal component) to the RMS value of the next largest noise or harmonic distortion component. SFDR is usually measured in dBc (with respect to the carrier frequency amplitude) or in dBFS (with respect to the ADC's full-scale range).

In DACs, Spurious-Free Dynamic Range (SFDR) is the ratio of the RMS amplitude of the carrier frequency (maximum signal components) to the RMS value of their next largest distortion component. SFDR is usually measured in dBc (with respect to the carrier frequency amplitude) or in dBFS (with respect to the DAC's full-scale range). Depending on the test condition, SFDR is observed within a pre-defined window or to Nyquist.

Also see the Maxim Data Conversion Calculator.

The rush of current that occurs while both devices are on is called the shoot-through current. Events that allow both devices to be on (e.g. circuit faults or a brief moment in the switching cycle) are said to "crowbar" the circuit because of its similarity to a power supply protection circuit of that name.

See: Protection and Isolation products.

2. Standard Military Drawing (SMD): A U.S. government program for standardized MIL-STD-883 product specifications, to simplify military procurement. Sponsored by the DSCC (Defense Supply Center, Columbus).

2. A "voltage source" or "current source" is an idealized generator of voltage or current in a circuit. These sources can be AC or DC, controlled or constant.

Spread-spectrum techniques can also be used to reduce electromagnetic interference by dithering the clock frequency so emissions are no longer concentrated at one frequency.

See:

• An Introduction to Direct-Sequence Spread-Spectrum Communications
• Low-EMI, Class D Audio Power Amplifiers with Spread-Spectrum Modulation
• About Spread-Spectrum Oscillators

Maxim offers a range of products for STB designers. See: Set-Top Box Solutions page.

Also See: Silicon Timed Circuits (Delay Lines): Frequently Asked Questions

2. System Timing and Control: Clock generation and distribution systems and components. May include the means for clock control such as spread-spectrum clock generation for EMI reduction, skew rate control, rate dividers, rate control, width, delay, and phase adjustment.

Also See: System Timing and Control Design Guide (PDF) and the Clock Generation and Distribution product line page.

The swallow counter is used to control the dual-modulus prescaler which is set to either N or (N+1). At the initial reset state, the prescaler is set to a divide ratio of (N+1), but the swallow counter will change this divide ratio to N when it finishes counting S number of cycles.

The Swallow Counter gets its name from the idea that it "swallows" 1 from (N+1) of the dual-modulus prescaler.

See: DC-DC Converter Tutorial

For a pot with a linear taper, the resistance varies linearly as the wiper moves.

For a pot with a logarithmic (log) taper, the resistance varies logarithmically with the wiper's motion. When used in an amplifier circuit, the output varies slowly as the pot is operated at the low end and varies more and more rapidly as the pot is operated toward the high end.

This is also called an audio taper because it is most commonly used for audio volume controls. The ear responds logarithmically (each doubling in signal is perceived as an equal step in volume). The ear is more sensitive to changes at lower volumes, so an audio volume control varies the signal slowly at lower settings and more rapidly at higher settings. The net effect is that the sound seems to vary smoothly through the pot's range.

The perceived volume is subjective and fairly imprecise, so an approximation may be used instead of a true log pot. Example: See application notes AN 3996, AN 838, AN 1828.

The small size of the TEC allows precision thermal control of individual components such as fiber optic laser drivers, precision voltage references, or any other temperature critical device. Temperature-critical components are integrated with a TEC and a temperature monitor into a single thermally-engineered module.

A "thermoelectric controller" (also abbreviated TEC) is an electronic circuit that controls the current that drives the junction. These can be quite sophisticated. Many can drive a positive or negative current (so they can heat or cool), use PWM for efficiency, and incorporate control to regulate the amount of current. Examples of such circuits are linked below.

See: App Note 3318, HFAN-08.2.0: Thermoelectric Cooler (TEC) Control.

See: Video Basics

See: Maxim's full line of thermal management integrated circuits.

As an example, if a 12kHz signal is applied to the input, THD would look at energy on the output occurring at 24kHz, 36kHz, 48kHz, etc. and compare it to the energy occurring at 12kHz.

Common misspellings: Transciever, Tranceiver, Transeiver, Transiever, Tranciever, Transcever.

Examples:

• Interface devices (such as line drivers and receivers, RS-232, RS-485, RS-422, CAN, LVDS, or USB)
• Wired communications ICs, such as T1/E1/J1 Transceivers (LIU and Framer) and T3/E3 Transceivers
• Wireless communications such as IF and RF transceivers

The term derives from "transfer conductance" and is measured in siemens (S), where 1 siemens = 1 ampere per volt. It was formerly measured as "mho" (ohm spelled backwards).

The term derives from "transfer conductance" and is measured in siemens (S), where 1 siemens = 1 ampere per volt. It is represented with the symbol g_m. The basic gain of vacuum tubes and FETs is expressed as transconductance.

See: Transconductance Amplifier Buffers Current Transformer

The number of data transfers is less than the number of bits transmitted when encoded data has more bits than the raw data. As an example, a PCIe serial bus uses 10 bits to encode eight data bits. (Extra bit space may be used to encode a clock, error-detection redundancy, etc.)

Data rates are commonly expressed in transfers per second, gigatransfers per second (GT/s) and megatransfers per second (MT/s).

A transformer consists of two magnetically coupled coils. Alternating current in one (called the "primary") creates a changing magnetic field which induces a current in the second coil (the "secondary"). A core made of iron or ferrite generally connects the two coils, but higher frequency devices can work without a ferrous core.

Transformers have two primary functions: Voltage transformation and isolation:

• The voltage of the secondary can be higher or lower than the voltage that drives the primary and is determined by the ratio of turns of wire in the two coils.
• Isolation refers to the fact that the coils are connected only by a magnetic field, so they can be independent of a common ground.

Primary applications are for power and for signal isolation / impedance transformation.

An autotransformer is a transformer with a single coil with intermediate "taps" to effect the changed outgoing voltages. They do not provide isolation.

Transformer capacity is rated in kilovolt-amps (KVA): The volts x amps / 1000.

The unit for transresistance is the ohm.

See: Transconductance Amplifier Buffers Current Transformer

Usually built from silicon but can be constructed from other semiconductor materials. There are two major types: The FET (field-effect transistor) and the bipolar junction transistor (BJT).

The first transistor was invented in 1947 at Bell Labs by Michael John Bardeen, Walter Brattain and William Shockley.

Examples:

• A radio transmitter that modulates the signal on a carrier and transmits it over the airwaves
• An ultrasonic transducer that sends the signal over ultrasound frequencies
• A line driver that drives a backplane
• A circuit that drives an interface (e.g., USB, serial, LVDS)
• A fiber optic device that emits light pulses

Commonly used for a bus, in which any several devices can be selected. If the bus has a pull-down resistor, the tri-state arrangement achieves an OR function, dubbed "wired-OR."

Tri-State is a trademark of National Semiconductor.

Often written as uA, but the u is a plain-text substitute for the Greek letter mu.

See: UART-related application notes

Mbps=million bits per second.

UWB is the modern version of older "impulse" technologies which are generated by very short pulses (impulse waveforms). They were called "carrier-free" or "baseband" because the energy is so widespread in the frequency domain that there is no discernible carrier frequency.

For a crude example, connect a metal file to one terminal of a battery and a wire to the other terminal. Brush the wire across the teeth of the file and note that the electrical noise can be heard on a radio tuned to just about any frequency.

The FCC authorizes UWB between 3.1 and 10.6GHz (but is not likely to approve devices that rely on a file and a wire.)

Examples: V_CC is a positive-voltage supply and the collector terminal of bipolar transistors is connected to the V_CC supply or to a load which connects to V_CC. V_SS connects to the source terminal of a FET, etc.

V+ and V- are also common ways to refer to a supply voltage.

The term originated in the 1970s along with "SSI" (small-scale integration), "LSI" (large-scale), and several others, defined by the number of transistors or gates per IC. It was all a bit silly since improving technology obviously makes numerical definitions meaningless over time. And it varies by industry -- a VLSI analog part is quite different from a VLSI digital logic part or a VLSI memory part.

Eventually, the pundits began trying terms like "ULSI" (ultra-large-scale). Engineers, meanwhile, ignored it all and spent their time building better devices instead of making up new words for them.

The terms LSI and VLSI are now usually used as general terms, referring to a product or technology that subjectively has more devices than typical products in the category. Maxim has observed a technical trend in analog and mixed signal toward increasing complexity. Many of our parts include complex control, such as the MAXQ microcontroller core, with many times more devices than most analog parts.

Using a common plumbing analogy, voltage is similar to water pressure and current is analogous to flow (e.g. liters per minute).

In equations, the symbol E is often used (as in: E = IR). V is the symbol for the unit of measure, Volt.

Electrical power is measured in watts (W): The voltage times the current measured each instant. In a direct current system or for resistive loads, the wattage and VA measurements will be identical. But for reactive loads, the voltage and current are out of phase and the volt-ampere spec will be greater than the wattage.

For determining power, watts are appropriate. For determining capacity for the driving circuits (circuit breakers, wiring, and uninterruptible power supplies, for instance), VA is appropriate.

In an ideal system, 100% of the energy is transmitted. This requires an exact match between the source impedance, the characteristic impedance of the transmission line and all its connectors, and the load's impedance. The signal's AC voltage will be the same from end to end since it runs through without interference.

In real systems, mismatched impedances cause some of the power to be reflected back toward the source (like an echo). Reflections cause destructive interference, leading to peaks and valleys in the voltage at various times and distances along the line.

VSWR measures these voltage variances. It is the ratio of the highest voltage anywhere along the transmission line to the lowest. Since the voltage doesn't vary in an ideal system, its VSWR is 1.0 (or, as commonly expressed, 1:1). When reflections occur, the voltages vary and VSWR is higher -- 1.2 (or 1.2:1), for instance.

Mathematically:

VSWR is the voltage ratio of the signal on the transmission line:

VSWR = |V(max)| / |V(min)|

where V(max) is the maximum voltage of the signal along the line, and V(min) is the minimum voltage along the line.

It can also be derived from the impedances:

VSWR = (1+)/(1-)

where (gamma) is the voltage reflection coefficient near the load, derived from the load impeadance (ZL) and the source impedance (Zo):

= (ZL-Zo)/(ZL+Zo)

If the load and transmission line are matched, = 0, and VSWR = 1.0 (or 1:1).

  Watts = Volts x Amps x Power Factor

The power factor can be disregarded for DC circuits or for AC circuits with a resistive load (it is 1 in those situations).

The wafer is then sliced into "dice" which are mounted in packages, creating the IC.

While Wi-Fi (802.11) covers a small area with a radius of a few hundred meters, WiMax (802.16) can cover up to 6 miles with only one base station.

Also known as WirelessMAN, for "Wireless Metropolitan Area Networks."

The different nomenclatures for the color components reflect different color encoding schemes.

See: Video Basics;