what is analog crosspoint switch
analog crosspoint switches are used for routing high speed signals such as video and audio signals. They are used in many different applications, and vary in terms of configuration and performance. IC analog crosspoint switches are available in six basic configurations: 8×8, 16×4, 16×8, 16×16, 32x 16, and 32×32. For each configuration, the first number represents the numbers of inputs and the last number represents the number of output crosspoint. Performance specifications for IC analog crosspoint switches consist of supply voltage, bandwidth, slew rate, maximum crosstalk, and operating ambient temperature. Supply voltage is the source voltage range. Bandwidth is the device’s ability to provide a maximum output voltage swing with increasing frequency. Slew rate is the rate of change of the output voltage in response to a step input. Maximum crosstalk is measured in decibels (dB) and represents the channel-to-channel crosstalk between any two analog inputs.
IC analog crosspoint switches differ in terms of applications and features. Some products are designed for audio, automotive, avionics, commercial, communications, computers, or data acquisition applications. Others meet mechanical, electrical and environmental requirements for industrial, medical, military, or video applications. IC analog crosspoint switches for portable devices and universal serial bus (USB) products are also available. In terms of features, IC analog switches may incorporate fault-tolerant protection, short circuit protection, thermal protection, or on-chip electrostatic discharge (ESD) protection. Bilateral switches allow signals to be transmitted in either direction. Chip-enabled switches can be enabled or disabled by applying a logic signal to the chip enable (CE) pin. IC analog crosspoint switches with serial inputs and undervoltage lockouts provide additional flexibility and protection.
Re: what is analog crosspoint switch
analog switches are integrated circuits (ICs) that allow electric current to flow when closed and prevent current from flowing when open. They are often used to interface analog signals to digital controllers. IC analog switches differ in terms of the number of poles or contacts, and the number of positions or throws. Common pole and throw configurations are single-pole, single-throw (SPST); single-pole, double-throw (SPDT); double-pole, single-throw (DPST), and double-pole, double throw (DPDT). SPST switches make or break the connection of a single conductor in a single branch circuit. They typically have two terminals. SPDT switches also make or break the connection of a single conductor, but with either of two other conductors. These switches, which often have three terminals, are commonly used in pairs as three-way switches. DPST switches, another type of double-pole device, make or break the connections of two circuit conductors in a single branch circuit. Normally, DPST switches have four terminals. Finally, DPDT switches make or break the connections of two conductors to two separate circuits. These switches usually have six terminals.
Performance specifications for IC analog switches include maximum resistance, propagation delay, minimum operating current, power dissipation, and operating ambient temperature. Some devices include a bilateral feature that allows signals to be transmitted in either direction. Others are radiation tolerant or provide protection against overcurrent and electrostatic discharge (ESD). IC analog switches that meet military specifications (MIL-SPEC) and military standards (MIL-STD) are also available. Supply voltages range from -5 V to 5 V.
IC analog switches is available in a variety of IC package types. Examples include ball grid array (BGA), quad flat package (QFP), dual in-line package (DIP), and small outline package (SOP). BGA places output pins in a solder ball matrix and offers reduced package size and improved heat dissipation. Variants include plastic-ball grid array (PBGA), tape-ball grid array (TBGA), and fine-pitch land grid array (FLGA). QFP devices contain a large number of fine, flexible, gull winged shaped leads. Low-profile quad flat package (LFQP) and thin quad flat package (TQFP) are common QFP variants. DIPs can be installed in sockets or soldered into holes that extend into the surface of printed circuit boards (PCBs). They are often made from plastic (PDIP) or ceramic (CDIP). SOP variants include small outline IC (SOIC), shrink small outline package (SSOP), thin small outline package (TSOP), thin very small outline package (TVSOP), and small outline flat-leaded package with heat sink (HSOF). Small outline J-lead (SOJ) is a common form of surface-mount packaging. Plastic leaded chip carrier (PLCC) and leadless ceramic chip carrier (LCCC) are other package types for IC analog switches.
Selecting IC analog switches requires an analysis of logic families. Transistor-transistor logic (TTL) and related technologies such as Fairchild advanced Schottky TTL (FAST) use transistors as digital switches.