engineering

Mixed-signal integrated circuit

Mixed-signal integrated circuit is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Mixed-signal integrated circuit rather than just read about it. In short: A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die. Their usage has grown dramatically with the increased use of cell phones, telecommunications, portable electronics, and automobiles with electronics and digital sensors.

Key takeaways

Mixed-signal integrated circuit belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Mixed-signal integrated circuit to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Mixed-signal integrated circuit from memory before moving on to harder problems.

Reference excerpt

A mixed-signal integrated circuit is any integrated circuit that has both analog circuits and digital circuits on a single semiconductor die. Their usage has grown dramatically with the increased use of cell phones, telecommunications, portable electronics, and automobiles with electronics and digital sensors.

Overview Integrated circuits (ICs) are generally classified as digital (e.g. a microprocessor) or analog (e.g. an operational amplifier). Mixed-signal ICs contain both digital and analog circuitry on the same chip, and sometimes embedded software. Mixed-signal ICs process both analog and digital signals together. For example, an analog-to-digital converter (ADC) is a typical mixed-signal circuit. Mixed-signal ICs are often used to convert analog signals to digital signals so that digital devices can process them. For example, mixed-signal ICs are essential components for FM tuners in digital products such as media players, which have digital amplifiers. Any analog signal can be digitized using a very basic ADC, and the smallest and most energy efficient of these are mixed-signal ICs. Mixed-signal ICs are more difficult to design and manufacture than analog-only or digital-only integrated circuits. For example, an efficient mixed-signal IC may have its digital and analog components share a common power supply. However, analog and digital components have very different power needs and consumption characteristics, which makes this a non-trivial goal in chip design. Mixed-signal functionality involves both traditional active elements (like transistors) and well-performing passive elements (like coils, capacitors, and resistors) on the same chip. This requires additional modelling understanding and options from manufacturing technologies. High voltage transistors might be needed in the power management functions on a chip with digital functionality, possibly with a low-power CMOS processor system. Some advanced mixed-signal technologies may enable combining analog sensor elements (like pressure sensors or imaging diodes) on the same chip with an ADC. Typically, mixed-signal ICs do not necessarily need the fastest digital performance. Instead, they need more mature models of active and passive elements for more accurate simulations and verification, such as for testability planning and reliability estimations. Therefore, mixed-signal circuits are typically realized with larger line widths than the highest speed and densest digital logic, and the implementation technologies can be two to four generations behind the latest digital-only implementation technologies. Additionally, mixed signal processing may need passive elements like resistors, capacitors, and coils, which may require specialized metal, dielectric layers, or similar adaptations of standard fabrication processes. Because of these specific requirements, mixed-signal ICs and digital ICs can have different manufacturers (known as foundries).

Applications There are numerous applications of mixed-signal integrated circuits, such as in mobile phones, modern radio and telecommunication systems, sensor systems with on-chip standardized digital interfaces (including I2C, UART, SPI, or CAN), voice-related signal processing, aerospace and space electronics, the Internet of things (IoT), unmanned aerial vehicles (UAVs), and automotive and other electrical vehicles. Mixed-signal circuits or systems are typically cost-effective solutions, such as for building modern consumer electronics and in industrial, medical, measurement, and space applications. Examples of mixed-signal integrated circuits include data converters using delta-sigma modulation, analog-to-digital converters and digital-to-analog converters using error detection and correction, and digital radio chips. Digitally controlled sound chips are also mixed-signal circuits. With the advent of cellular and network technology, this category now includes cellular telephone, software radio, and LAN and WAN router integrated circuits.

Design and development Typically, mixed-signal chips perform some whole function or sub-function in a larger assembly, such as the radio subsystem of a cell phone, or the read data path and laser SLED control logic of a DVD player. Mixed-signal ICs often contain an entire system-on-a-chip. They may also contain on-chip memory blocks (like OTP), which complicates the manufacturing compared to analog ICs. A mixed-signal IC minimizes off-chip interconnects between digital and analog functionality in the system—typically reducing size and weight due to minimized packaging and a smaller module substrate—and therefore increases the reliability of the system. Because of the use of both digital signal processing and analog circuitry, mixed-signal ICs are usually designed for a very specific purpose. Their design requires a high level of expertise and careful use of computer aided design (CAD) tools. There also exists specific design tools (like mixed-signal simulators) or description languages (like VHDL-AMS). Automated testing of the finished chips can also be challenging. Teradyne, Keysight, and Advantest are the major suppliers of the test equipment for mixed-signal chips. There are several particular challenges of mixed-signal circuit manufacturing:

… excerpt ends here. Continue reading the full article.

Illustrations

Mixed-signal integrated circuit: Mixed signal integrated circuit: the metal areas on the right-hand side are capacitors, on top of which are large output transistors; the left-hand side is occupied by the digital logic — Mixed signal integrated circuit: the metal areas on the right-hand side are capacitors, on top of which are large output transistors; the left-hand side is occupied by the digital logic

Worked examples

Example 1 — a first encounter with Mixed-signal integrated circuit

Start with the simplest possible case. Write down what Mixed-signal integrated circuit claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Mixed-signal integrated circuit before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Mixed-signal integrated circuit ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Mixed-signal integrated circuit

In research: Mixed-signal integrated circuit appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Mixed-signal integrated circuit in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Mixed-signal integrated circuit is common in secondary-school and first-year university syllabi. It links to neighbouring topics Electronic design, so understanding it makes those chapters shorter.
In everyday life: Look for Mixed-signal integrated circuit outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Mixed-signal integrated circuit” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Mixed-signal integrated circuit in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Mixed-signal integrated circuit means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Mixed-signal integrated circuit out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Mixed-signal integrated circuit in simple terms?

Why does Mixed-signal integrated circuit matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Mixed-signal integrated circuit?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Mixed-signal integrated circuit.