Integrated circuit plate

Circuit boards according to their function, different structures can be divided into analog and digital circuit boards into two categories. Simulation is used to generate, amplify and process a variety of analog signals (refer to the magnitude of the frontier with time-varying signals, audio signals such as transistor radios, tape recorders signals, etc.), and the number used to generate, amplify, and a variety of digital signal processing (refer to the on time and amplitude values ​​of the discrete signal, e.g. VCD, DVD reproducing audio and video signals).

2 Press the production process of

According to the production process can be divided into semiconductors and thin film, wherein the film is also divided into thick and thin film.

3 Press highly integrated low scores

According to the level of integration can be divided into small, medium size, large-scale and ultra large scale.

4 Press the conductivity type of

By conductivity type can be divided into bipolar and unipolar. Bipolar production process complicated, large-power, representatives TTL, ECL, HTL, LST-TL, STTL other types; unipolar production process is simple, low power consumption, ease into a large-scale, on behalf of There CMOS, NMOS, PMOS and other types.

5 points according to a variety of uses

Use can be divided into the TV to use, with audio, video machine, VCR, computer (PC) to use, keyboard use, communication, camera use, remote control, language, and various special alarm Used.

TV by including horizontal and vertical scanning, medium, sound, color decoding, AV / TV converter, switching power supply, remote control, NICAM decoding, picture in picture processing, microprocessor (CPU), memory, etc..

Sound by including AM / FM high-frequency circuits, stereo decoding circuitry, audio preamplifier circuit, audio operational amplifier, audio power amplifier, surround sound processing, level drive, electronic volume control, delay reverb, electronic switches. Discs with machine control systems, video encoding, MPEG decoding, audio signal processing, sound effects, RF signal processing, digital signal processing, the servo motor drives.

VCR has a control system, servo drive, audio processing, video processing.

Production process

1, print circuit board. Will draw a good printed circuit board with iron-on transfers, pay attention to slippery side facing you, general printing two circuit boards, that piece of paper to print two circuit boards. In which you select the best printing circuit board production.

2, CCL-plate cutting board full graphic production. CCL, which is coated on both sides with a copper film circuit board, cut to the size of the copper-clad circuit board, not too large, in order to save material.

3, pretreatment CCL. With fine sandpaper to polish the surface oxide layer CCL out to ensure that when the circuit board transfer, thermal transfer paper, the toner can be securely printed on CCL, a good polished surface bright standard plate, no significant stains.

4, the transfer board. The printed circuit board cut to the appropriate size, the printed circuit board attached to the side of the CCL, CCL align well placed after the transfer machine, when placed on transfers must ensure there is no dislocation. Generally 2-3 times after the transfer, the board will be able to transfer it firmly on the CCL. Heat transfer machine beforehand had been preheated, the temperature set at 160-200 degrees Celsius, pay attention to safety due to the high temperature operation!

5, corrosion PCB reflow machine. First check whether the transfer complete circuit board, if the minority is no good place to transfer oil pen with black patches. Then you can corrode, and so when the copper film exposed circuit board completely eroded, the board removed from the etching solution to clean, such a circuit board on the corrosion better. The composition of the etching solution of concentrated hydrochloric acid, hydrogen peroxide, water, the proportion of 1:2:3, in the preparation of the etching solution, the first drain, plus concentrated hydrochloric acid, hydrogen peroxide, if the operation of concentrated hydrochloric acid, hydrogen peroxide or an etching solution does not Carefully splashed on skin or clothing should be promptly cleaned with water, due to the use of highly corrosive solution, we must pay attention to safety when operating!

6, circuit board drilling. The circuit board is to insert electronic components, so they are on the circuit board drilling. Select electronic components based on the thickness of different pin bur when using the drilling rig, the board must act in stable rig slow speed can not be opened, the operating rig is quite simple, can be done very well as long as careful . Please see the operating personnel to operate carefully.

7, circuit board pretreatment. After drilling, use fine sandpaper to cover the circuit board toner polished off with water to clean circuit boards. After the water dried, coated with pine fragrance line side there is just a thin layer, not only to prevent oxidation of the line, but also a good rosin flux, in general, the surface of the circuit board pine fragrance will be within 24 hours solidification, to accelerate the solidification of rosin, we use hot air heating circuit boards, only 2-3 minutes rosin can solidify. Hot air temperatures up to 300 degrees, not toward the outlet when using flammable, and the small animals, or a request for safety first ah!

8, for soldering electronic components. After the board for soldering electronic components, power, function realization, the production is completed.

And the difference between integrated circuits

IC replaced the transistor, for the development of the various functions of electronic products paved the way, and dramatically reduce the cost, the third generation of electronic devices from on stage. Its birth, the emergence of the microprocessor has become possible, but also to ordinary computer into an everyday tool can get close. Application Integration technology spawned more convenient electronic products, such as common handheld electronic calculator, Kilby Following is a new invention of the integrated circuit after. Until today, the silicon material is still the main material of our electronic devices.

In 1958, Texas Instruments' Kilby young engineers working to come up with a good idea, not only in the manufacture of transistors on a silicon wafer, silicon also allows the incorporation of other different elements in a particular area can be controlled, be made to change its conductivity resistance; then plated with a metal capacitor formed in a specific area of ​​the oxide layer formed on the wafer surface; circuit according to design requirements and to connect them to each other, so that a small piece of silicon wafer having an electronic circuit functions, known as integrated circuits, it is like a city under the microscope.

The integrated circuit of the invention is a revolutionary technology of electronic products, and further reduce the size of electronic devices, whereby they become lighter and smaller. Since most of the different electronic components can be fabricated on the same piece of silicon, closely linked to each other, thereby reducing the possibility of component failure and fracture of the lead, to improve the reliability of electronic equipment, but also reduces the manufacturing cost of the electronic products . In order to fully reflect the superiority of the integrated circuit, the people competing to improve the process, and strive to create more and more electronic components on the same size silicon. The early 1960s, making it only a small piece of silicon integrated circuit contains dozens of elements; late 1970s, people have been able to integrate 130,000 transistors in the area of ​​30 mm2 piece of silicon; Since the 1990s, the rapid development of VLSI technology, people have been able to on a fingernail-sized silicon chip making contains 5,000,000 transistors integrated circuits, it is functionally equivalent to 250 computer in 1945 invention , and then the first computer weighs 30 tons, to be occupied by two houses.

The invention of the integrated circuit, greatly reducing the cost of electronic products, miraculously reduce their size, leading to a home computer and cell phones have enabled electronic devices in the past in order to purchase specialized agencies may become a tool for public use.

Electronic devices with integrated circuit manufacturing of cheap, compact, reliable, convenient, people who admiration of electronic technology, the rapid expansion of their applications to many fields of human activity, making it a powerful means of conventional technology innovation, effectively improve the level of human activity.

Repair method

First, detection method of an integrated circuit

Now electronic products often due to an integrated circuit is damaged, causing part or parts not work properly, affecting the normal use of the device. So how to detect IC and the bad? Usually a device which has a plurality of integrated circuits, when to get a faulty integrated circuit device, first according to the failure phenomenon, largely determine the fault location, and then measurement, the possible failure of parts gradually narrowing, and finally found the fault lies. To find the fault must be detected, usually repair personnel pin voltage measurement methods are used to determine, but only to determine the approximate site of the fault, and some pin insensitive reaction, even some no response. Voltage deviation is the case, and also includes external components damaged factors must also be manifold internal fault and strict distinction between peripheral fault, and therefore rely on a particular method of integrated circuit is difficult to detect, and must rely on integrated means of detection.

Multimeter now to detect, for example, describes the specific methods. We know manifold used, there is always a pin printed circuit board "ground" wire is welded pass, called ground pin in the circuit. Due to the direct coupling of integrated circuits internally, therefore, there is a manifold between the pin and ground pin other DC resistance determined, such a determination is called the DC resistance of the foot equivalent internal DC resistance, referred to as the R. When we get a new manifold, it can by using a multimeter to measure the internal DC resistance of each pin is equivalent to judge its quality, the interior of each pin if the equivalent resistance R consistent with the standard value, indicating that this Manifold is good, whereas if the difference is too big and the standard value, indicating manifold internal damage.

It should be noted when measuring, because there are a lot of internal manifold transistors, diodes and other nonlinear elements, in the measurement of a single measured resistance can not judge its quality must be measured once again interchangeable pen, get forward and backward two resistance. Only when the resistance R pros and cons to both meet the criteria to determine the manifold intact. In actual repairs, usually measured on the road. First measure the pin voltage, if the voltage is abnormal, you can disconnect the connection pin terminal voltage measurements to determine the voltage change is caused by external components, or cause internal manifold. You can also use an external sensing circuit to the DC equivalent resistance (called R,) to ground to determine, DC resistance is usually measured in the circuit of a manifold between the pin and ground pin (on the road resistance), the actual R and R, are in the parallel equivalent resistance of the total current. In combination with the use of the road resistance measurement method in road repairs often voltage. Sometimes on the road and on the road resistive voltage deviation from the standard value, not necessarily the manifold damage, but the damage related to peripheral components, so that R, is not normal, resulting in abnormal circuit voltage and resistance on the road. At this time we can only measure the manifold internal DC equivalent resistance, in order to determine whether the damage manifold.

According to the actual repair experience, may not have the manifold welded on the road to detect IC internal resistance from the DC equivalent circuit down, just off the road resistive voltage or abnormal foot with the circuit, while the feet and the ground circuit board is disconnected, the other foot to maintain the status quo, to measure the R test pin and ground pin between positive and negative resistance value can be judged good
Bad. For example, the TV manifold TA7609P Rong foot abnormal voltage or resistance on the road, you can cut off the feet and Rong ⑤ feet (GND) and then use the multimeter to measure electrical resistance between the barrier Rong ⑤ feet and legs, a value measured after Swap table pen test once again. If the manifold shall be measured normal ground red pen to 8.2kΩ, black pen grounded within 272kΩ DC equivalent resistance of R, otherwise manifold is damaged. Most of the pin in the measurement, the multimeter with R × 1k block, when the individual pins R is large, the switch to R × 10k block, this is because R × 1k block within its table cell voltage is only 1.5V, when the manifold When the internal transistor series more, the meter voltage is too low for the manifold transistor into normal working condition, the value can not be revealed or inaccurate. In short, when it detects a careful analysis, flexible use of various methods, explore the law, so quickly, accurately identify the fault.

Second, the introduction of the integrated circuit to detect experience

(A) commonly used detection methods commonly used detection methods are integrated line measurement method, non-line measurement and substitution method.

A non-line measurement of non-line measurement when the tide is not integrated into the welding circuit, the DC resistance by measuring its DC resistance between each pin of the same model with a known normal IC comparison between each pin, to determine whether it is normal.

2-line measurement using the measurement line voltage measurement, the resistance measurement and the current measurement method, by measuring the voltage value of each pin of the integrated circuit on the circuit, the resistance value and the current value is normal, to determine whether the integrated circuit damage.

3 substitution method substitution method is well-known in the same model, same size IC to IC substitution test, can determine whether the damage to the IC.

(B) integrated circuits used to detect

A microprocessor integrated circuit testing microprocessor integrated circuits is a key test pin VDD power supply terminal, RESET reset terminal, XIN oscillator signal input, XOUT oscillator signal output lines and other various inputs and outputs. These key way to measure the foot on the ground in the resistance and voltage values, to see whether the normal (circuit diagram can be found from the product or service related information in) the same. Different types of microprocessors RESET reset voltage is not the same, some low reset, that moment is low in power, to maintain a high level after reset; some high reset, that is, switching instants is high, maintain low after reset.

Switching power supply IC detects the key pin voltage switching power supply IC 2. The power supply terminal (VCC), the excitation pulse output, voltage detection input current detection input. Measure each pin to ground voltage and resistance values, if the normal large difference in its peripheral components under normal circumstances, can determine the IC is damaged. Built-in power switch thick film integrated circuits, but also through the positive and negative resistance measurement switch C, B, E pole between the switch to determine whether it is normal.

3 When the audio amplifier IC audio amplifier IC testing checks should first detect the power supply terminal (positive and negative power supply terminal end), audio inputs, audio output and feedback terminal voltage and resistance values ​​of the land. If the measured value of each pin and normal data big difference, its peripheral components and normal, it is the IC internal damage. When the cause of the failure of a silent audio amplifier IC, measure its normal power supply voltage, signal interference method can be used to check. Measurement, the multimeter should be placed in R × 1 files, grounding the red pen with black pen touch audio inputs, normal speakers should be stronger, "Titicaca" sound.

4 detects the operational amplifier integrated circuit DC voltage profile with a multimeter, measure the output of the operational amplifier and the negative voltage between the power supply terminal (the high voltage static). Followed with a handheld metal tweezers touch the two op-amp inputs (adding the interfering signal), multimeter hands if there was a substantial swing, then the op amp intact; If the meter does not move the hands, then the op amp is damaged.

5 When the base when the base integrated circuit testing integrated circuits containing digital and analog circuits with a multimeter is difficult to directly measure its good or bad. Test circuit consists of resistive and capacitive components, light-emitting diode LED, 6V DC power supply, the power switch S and 8 pin IC socket components. The time-base integrated circuit (such as NE555) IC socket after inserting the letter, press the power switch S, if the measured time-base integrated circuit is normal, light-emitting diode LED will flash light; If the LED is not lit or has been lit, the measured bad time base circuit performance.

Third, the IC substitution technique

(A) direct substitution direct substitution refers to other IC directly without any changes to replace the original IC, the substitution does not affect the main performance indicators of the machine.

Its substitution principle is: IC substitution of several aspects of functionality, performance indicators, package, pin purposes, such as pin number and spacing are the same. Wherein the IC is the same function not only refer to the same function; same logic polarity should also be noted that the polarity of the input level of the output voltage, current amplitude must be the same. For example: the image put IC, TA7607 and TA7611, the former high-level radioactive reverse AGC, which was put forward high AGC, it can not direct substitution. In addition there are different polarity AFT output voltage, output sync pulses of different polarity, such as IC are not directly substitution, even the same 270 _f8 companies or manufacturers of products, should pay attention to distinguish. Performance is the main electrical parameters (or primary characteristic curve) IC, the maximum power dissipation, the maximum operating voltage, frequency range and each signal input and output impedance parameters to be similar to the original IC. Alternative power small pieces to increase the heat sink.

1, the same substitution of the same type IC IC substitution model is generally reliable, the installation of integrated circuits, pay attention to the direction of no mistake, otherwise, when the power IC is likely to be burned. Some single in-line amplifier IC, although the models, features the same characteristics, but the direction pinout order is different. For example, two-channel amplifier IC LA4507, whose pin has a "positive" and "anti" parts, their different starting foot mark (colored dots or pits) direction; no suffix with the suffix "R" of the IC, For example M5115P and M5115RP.

2, different types of IC substitution

(1) Model prefix the same letter, the substitution of different digital IC's. This substitution as long as the pin functions are identical to each other, its internal circuitry and electrical parameters slightly different, but also with each other directly substitution. Such as: audio amp IC LA1363 and the LA1365, the latter is the first ⑤ feet inside the IC adds a Zener diode, the other exactly the same.

(2) Number of different prefix letters, numbers, the same IC substitution. Under normal circumstances, the prefix letter is a class manufacturers and circuit prefix followed by the same number of letters, most of the direct substitution. But a few, although the same number, but the functionality is completely different. For example, HA1364 is sound IC, and uPC1364 is color decoding IC; 4558,8 foot is operational amplifiers NJM4558, 14 feet is the CD4558 digital circuits; therefore both completely unable substitution.

(3) Number prefix letters and numbers are different IC substitution. Some manufacturers introduce unpackaged IC chip, and then processed into products by the factory named. There are certain parameters such as the indicators in order to improve product improvement. These products are used to name different models or models to be distinguished by a suffix. For example, AN380 and uPC1380 direct substitution; AN5620, TEA5620, DG5620 and other direct substitution.

(B) non-direct substitution of non-direct substitution refers not be direct substitution of the peripheral circuit IC slightly modified, changing the original pin arrangement or change individual components, so that the IC can become a method of substitution .

Substitution principle: IC substitution may be used with the original IC pin function is different, different shape, but the function to be identical to similar characteristics; After the substitution should not affect the performance of the original machine.

1, the substitution of different IC packages of the same type IC chip, but a different shape of the package, as long as the shape and arrangement of the original new device pin when the pin of the device for shaping substitution. For example, AFT circuit CA3064 and CA3064E, the former round package, radial pin; latter is dual in-line plastic package, both inside exactly the same characteristics, can be connected by pin functions. Double row IC AN7114, AN7115 and LA4100, LA4102 is basically the same package, pin and heat sink are just difference 180 °. AN5620 mentioned heatsink 16-pin dual in-line package, TEA5620 18-pin dual in-line package, 9,10 feet on the right IC, the equivalent AN5620 heat sink, the other two legs are arranged like the 9,10 feet can be used to link the ground.

2, the circuit functions the same but the individual pin function IC substitution substitution can be different according to the specific parameters of each model IC and instructions. As in the television AGC, video signal output has positive and negative differences, as long as the substitution can be affixed at the output end of the inverter.

3, of the same type but different pin function IC substitution of this substitution needs to change the external circuit and pin arrangement, which requires a certain theoretical knowledge, complete information and a wealth of practical experience and skills.

4, some empty legs should not be allowed inside the ground when the equivalent circuit and application circuits leads to foot some not marked, pin-out across the empty, not without ground, which leads to the foot of replacement or alternate feet, sometimes as an internal connection.

5, discrete components substitution substitution IC IC sometimes be discrete components are damaged portion, to restore function. Should be aware of before the substitution principle of the IC's internal functions, the normal voltage of each pin out of waveforms with peripheral components and the circuit works. Should also be considered:

(1) Remove the signal can be connected to the external circuit from the input of the IC;

(2) The signal processing peripheral circuits, can be connected to the next level within the integrated circuit to be re-treated (signal matching connection should not affect the main parameters and performance). As put IC is damaged, from the typical application circuit and the internal circuitry of view, put by the sound, the frequency discriminator and audio amplification stage into the available signal injection method to identify the damaged part, if the audio amplification partially damaged, the available discrete components instead.

6, the combination of substitution

Combination of substitution is part of the multi-block circuit inside the IC is not the same type of damage, re-assembled into a complete IC, IC method used to replace dysfunctional. Buy wife under IC situation is very applicable. But requires the use of IC internal circuit must have a good interface leads feet. Non-direct substitution is critical to find out the basic electrical parameters of mutual substitution of two IC, the relationship between the internal connection information equivalent circuit, the function of each pin, IC and external components.

The actual operation to be noted: (1) IC pin number order, do not pick the wrong; (2) to adapt to the characteristics of the IC substitution after peripheral circuit components connected to its corresponding change; (3 ) to be consistent with the IC supply voltage after the substitution, if the original circuit power supply voltage is high, you should try to buck; voltage is low, the IC substitution depends on whether the work; later (4) substitution to measure the quiescent current of the IC such as the current is much larger than normal, then the circuit may occur from shock, then subject to decoupling adjustments. If you gain some differences with the original, adjustable feedback resistor; (5) IC substitution input and output impedance to match the original circuit; check their driving ability; (6) when the changes to take full advantage of the original circuit pin holes and leads the board requires external leads neatly to avoid cross back and forth to check and prevent the circuit from shock, particularly to prevent high-frequency self-excited; (7) best before re-energizing the power supply Vcc connected in the circuit in a DC ammeter, resistor descending observed changes buck IC total current is normal; circuit board repair a more popular technology expertise, technology needs to learn the circuit board repair technicians to study the long-term persistence and hard work, many people engaged circuit board repair person, during the apprenticeship, it should stand to increase the pressure and quit boring work environment and career change; course, there are many young people enthusiastic about the electronics industry, carefully buried study technology.

About PCBway

PCBWay, PCB Prototype and Fabrication the Easy Way!