Integrated Circuit Brief Introduction

Section 1 Analog Integrated Circuits

Analog integrated circuits are widely used in various audio-visual equipment. Even though tape recorders, televisions, and audio equipment are known as "digital devices," they are inseparable from analog integrated circuits.

In fact, analog integrated circuits are more complicated to apply than digital integrated circuits. As long as the components of each digital integrated circuit are good, it can generally work according to the predetermined function. Even if the circuit does not work properly, it is relatively easy to repair. 1 is 1, 0 is 0, without ambiguity. Analog integrated circuits are different. Generally, a certain number of peripheral components are required to work with it. So, since it is an "integrated circuit", why don't all the peripheral components be built in? This is because of the limitations of the integrated circuit manufacturing process, and it is also to make the integrated circuit more adaptable to different application circuits.

Home appliance repair personnel are very concerned about the parameters of analog integrated circuits and the voltage of each pin online, and they rely on these to judge faults. For amateur electronics enthusiasts, it is enough to understand what commonly used integrated circuits are used for, and then look up relevant information when they are needed.

Many electronics enthusiasts start by installing radios and audio amplifiers. It is really fun to install them with integrated circuits. I believe everyone is interested in both. There are two types of radios installed. One is AM medium wave, which is usually installed with CIC7642 and TA7641 integrated blocks. The other is FM frequency modulation, which usually requires a certain level of skill and uses TDA7010, TDA7021, TDA7088, CXA1019 (CXA1191), CXA1238, etc. These integrated blocks are also classic ICs used by radio manufacturers.

CIC7642 looks like a 9013, has only three pins, works at 1.5V, and integrates multiple transistors. It is used to assemble a direct-play radio, and it is very easy to succeed, so it is indispensable in many electronic starter kits. Its compatible models are MK484 and YS414, and many imported miniature radios and electronic watch radios use it.

The radio assembled by TA7641P is a superheterodyne type with good performance, but because of the intermediate frequency, the production and debugging are a bit complicated. If you can buy a kit to assemble it, it is not a big deal.

The TDA7000 series is a product of Philips. There are TDA7000 that bitbaby has never seen, as well as TDA7010T, TDA7021T, and TDA7088T. The latter three have a suffix T, indicating that they are micro-chip packages.

CXA1019 is produced by Sony, and CXA1191 is its improved model. They are called single-chip AM/FM radio integrated circuits because one IC contains all functions from high-frequency amplification, local oscillation to intermediate frequency amplification and low-frequency (audio) amplification. CXA1238 is an AM/FM stereo radio integrated circuit. It does not include an audio amplifier, but has a stereo decoding function. It is usually used in WALKMAN radios, etc.

Here is a piece of knowledge: the same model of CXA radio IC has three different sizes (that is, the suffix M type is a surface mount package, the S type is a small package, and the P type is a DIP package).

TA7240P is a commonly used power amplifier IC in tape recorders. It has dual channels, 5.8W each, and a power supply of about 12V. The sound quality is average.

TDA1521 is a high-fidelity amplifier IC with high power and good sound quality. High-end computer active speakers also use this integrated circuit.

The application circuits of LM1875 (TDA2003, TDA2030, TDA2030A) are similar, but the power is different. TDA2030A is an improved version of TDA2030, with slightly higher power. These integrated blocks are also widely used, but there are also many fakes. Some fakes are made of cheap ICs, while others are crudely made.

A fool-proof amplifier is a thick-film integrated circuit, which is actually just a package of discrete components together. Only the input pins are used to connect the sound source, the output pins are connected to the speakers, and there is a power pin, which makes it convenient to use.

In addition, there are low-power audio amplifiers such as TDA2822 and LM386, which are used as power amplifiers in battery-powered products. They can also be used to make active speakers, and cheap active speakers use them.

The output current of CMOS integrated circuits is not very large, about 10mA, but in general electronic production, it is still no problem to drive an LED light-emitting diode.

Section 2 Voice Integrated Circuit

Music integrated circuits and speech integrated circuits are often used in electronic production, generally called speech chips and music chips. They are generally soft-encapsulated, that is, the chip is directly encapsulated on a small circuit board with black glue. Voice ICs generally require a small number of peripheral components to work, which can be directly soldered to this circuit board.

Although the voice IC application circuit is simple, it is indeed an integrated circuit containing thousands of transistor cores. It contains oscillators, metronomes, tone generators, ROMs, address calculators, and control output circuits. The music disc can store one or more world famous songs, and the price is very cheap, only a few cents a piece. Music doorbells are all installed with this kind of music disc, which is actually very low in cost.

Different language chips store various animal calls, short language, etc., and are more expensive than music chips. However, because they are interesting, they are used more and more. Talking calculators, reversing alarms, alarm clocks, etc. Although there are many varieties of voice circuits, they cannot make sounds according to the user's requirements at any time, because commercial voice products use mask technology, and the voice is fixed, which keeps the cost under control.

Generally, voice integrated circuit manufacturers can customize the voice content, but because of the need for masking, the number of pieces is required to be more than a thousand. The OTP voice circuit that has appeared in recent years has solved this problem. OTP means one-time programmable, which means that the chip produced by the manufacturer is empty, and the content is written by the user (device development is required). Once solidified, it can no longer be erased, and the information will not be lost. Its appearance provides convenience for developers to trial-produce prototypes, and is particularly suitable for small-batch production.

It is very convenient to use recordable and replayable speech circuits for amateur production, such as UM5506, ISD1400, ISD2500, etc., with very few peripheral components. The first time bitbaby learned about recordable and replayable speech integrated circuits was in a radio magazine in the 1990s. I remember that they were UM5101 and T6668, both of which used 41256 and other DRAMs. At that time, I really wanted to have a monster that could record without tapes, and could change the pitch at will during playback. Early digital answering machines also used them. Since they used DRAM, if there was no backup battery, all the information would be lost once the power was cut off.

The voice circuit using EEPROM has greatly facilitated electronic enthusiasts. It can record and play at any time, is not afraid of power failure, is easy to use, and has few peripheral components. It is just more expensive, costing about 1 yuan per second. The first choice for this type of voice recording and playback integrated circuit is the ISD series of ISD (USA). There are manufacturers in China that produce compatible chips and soft-encapsulated chips and modules, but judging from the structure, it is speculated that it comes from ISD.

Section 3 Digital Integrated Circuits

There are many types of digital integrated circuit products. Digital integrated circuits constitute various logic circuits, such as various gate circuits, encoders, triggers, counters, registers, etc. They are widely used in all aspects of life, from electronic watches to computers, all of which are composed of digital integrated circuits.

Structurally, they can be divided into two types: TTL and CMOS. The 74LS/HC series is the most common TTL circuit. They use a 5V voltage, the logic "0" output voltage is less than or equal to 0.2V, and the logic "1" output voltage is about 3V. CMOS digital integrated circuits have a wide operating voltage range, low static power consumption, and strong anti-interference ability, which are more advantageous. A feature of digital integrated circuits is their power supply pins. For example, for a 16-pin integrated circuit, the 8th pin is the negative pole of the power supply, and the 16th pin is the positive pole of the power supply; for a 14-pin integrated circuit, the 7th pin is the positive pole of the power supply.

Usually, the operating voltage range of CMOS integrated circuits is 3-18V, so it is not necessary to use a voltage of 5V like TTL integrated circuits. The input impedance of CMOS integrated circuits is very high, which means that the driving power consumed when driving CMOS integrated circuits can be almost ignored. At the same time, CMOS integrated circuits also consume very little power. Electronic products made with CMOS integrated circuits can usually be powered by dry batteries. In addition, CMOS integrated circuits have strong anti-interference capabilities, that is, the noise tolerance is large, and the higher the power supply voltage, the stronger the anti-interference capability.

Common digital integrated circuits used in electronic production include 4001, 4011, 4013, 4017, 4040, 4052, 4060, 4066, etc. It is recommended to buy more for backup. Most digital integrated circuits on the market are imported. The prefix of the product model represents the production company. Common ones include MC1XXXX (Motorola), CDXXXX (RCA), HEFXXXX (Philips), TCXXXX (Toshiba), HCXXXX (Hitachi), etc. Generally speaking, as long as the model is the same, products from different companies can be interchanged. Here is a table about the prefixes of integrated circuits and their production companies.

It should be noted that CMOS integrated circuits are easily broken down by static electricity, so they need to be properly stored. Generally, they should be placed in the original anti-static packaging strip, or wrapped in tin foil. In addition, when soldering, use a well-grounded electric soldering iron, or simply unplug the plug and use the residual heat to solder. But to be honest, the current CMOS integrated circuits have greatly improved their anti-static capabilities due to improved production processes. Many people don't pay much attention to anti-static for CMOS integrated circuits, but ICs are still alive.

Section 4 Three-terminal voltage regulator IC

The three-terminal voltage regulator integrated circuits commonly seen in electronic products include the 78×× series with positive voltage output and the 79×× series with negative voltage output. A three-terminal IC refers to an integrated circuit used for voltage regulation that has only three pins for output, namely the input terminal, the ground terminal, and the output terminal. It looks like an ordinary triode, with a standard TO-220 package, and also has a TO-92 package that looks like a 9013.

The 78/79 series three-terminal voltage regulator ICs require very few peripheral components to form a voltage regulator. The circuit also has overcurrent, overheating and adjustment tube protection circuits. It is reliable, convenient and cheap to use. The number after 78 or 79 in the model of this series of integrated voltage regulator ICs represents the output voltage of the three-terminal integrated voltage regulator circuit. For example, 7806 means the output voltage is positive 6V, and 7909 means the output voltage is negative 9V.

The 78/79 series three-terminal voltage regulator ICs are produced by many electronics manufacturers and have been around since the 1980s. They are usually prefixed with the manufacturer's code, such as TA7805 for Toshiba products and AN7909 for Panasonic products.

Sometimes there is an M or L after the number 78 or 79, such as 78M12 or 79L24, to distinguish the output current and package form, among which the maximum output current of the 78L series is 100mA, the maximum output current of the 78M series is 1A, and the maximum output current of the 78 series is 1.5A. There are also many kinds of packages, see the figure for details. The plastic packaged voltage regulator circuit has the advantages of easy installation and low price, so it is used more. In addition to the negative output voltage, the 79 series has a different pin arrangement, and the naming method and appearance are the same as the 78 series.

Because the three-terminal fixed integrated voltage regulator circuit is easy to use, it is often used in electronic production. It can be used to modify the voltage regulator power supply of discrete components and is also often used as the working power supply of electronic equipment. The circuit diagram is shown in the figure.

Note that the input, output and ground terminals of the three-terminal integrated voltage regulator circuit must not be connected incorrectly, otherwise it will burn out easily. Generally, the minimum input and output voltage difference of the three-terminal integrated voltage regulator circuit is about 2V, otherwise it cannot output a stable voltage. Generally, the voltage difference should be kept at 4-5V, that is, the voltage after transformer transformation, diode rectification and capacitor filtering should be higher than the voltage regulation value.

In practical applications, a sufficiently large heat sink should be installed on the three-terminal integrated voltage regulator circuit (of course, it is not necessary under low power conditions). When the temperature of the voltage regulator tube is too high, the voltage regulation performance will deteriorate or even be damaged.

When a voltage-stabilized power supply capable of outputting a current of more than 1.5A is needed in production, several three-terminal voltage-stabilized circuits are usually connected in parallel to make the maximum output current N times 1.5A. However, it should be noted that the integrated voltage-stabilized circuits used in parallel should be from the same manufacturer and the same batch number to ensure the consistency of parameters. In addition, a certain margin should be left in the output current to avoid the chain burning of other circuits when individual integrated voltage-stabilized circuits fail.