COROLLARY THEOREMS - ELECTRONINC DESIGN NOTES: Standard Logic ICs

Not only logic (digital) ICs are way more powerful, compared to analog electronics, but they are also a lot easier to work with. In fact, designing digital electronics may be as simple as playing with a Lego game. All you need for that is a good start, and our book LEARN HARDWARE FIRMWARE AND SOFTWARE DESIGN is, in truth, the best of the lot!

Now, many logic ICs are standard components, meaning, they are built by many manufacturers. That is a particularly important aspect when designing hardware, because you are not constrained to one manufacturer only. Always try to use standard components in your designs as much as it is (humanly) possible. In addition, you should remember that in firmware we can implement any hardware function. For example, an 8 pins Microchip controller of about 0.5 USD may be an excellent local driver, replacing few expensive ICs, and having plenty of upgradeable firmware intelligence. Firmware intelligence should always be preferred to hardware logic.

In this page are highlighted briefly few standard logic ICs, but you should be aware they are far more. The structure used to present families of ICs is:
1. Types of standard ICs
2. Standard Logic ICs

NOTE
The basic notions highlighted in this page are related to few electronic design topics presented in the first part, Hardware Design, of LEARN HARDWARE FIRMWARE AND SOFTWARE DESIGN.

TYPES OF STANDARD ICs

There are five major types of standard Logic ICs as follows:
1. Resistor Transistor Logic (RTL)
2. Diode Transistor Logic (DTL)
3. Transistor-Transistor Logic (TTL)
4. Emitter Coupled Logic (ECL)
5. Complementary MOS Logic (CMOS)

Only TTL and CMOS types are presented here because they are the most important.

COMPARISON CHART TTL AND CMOS STANDARD ICs
Parameter	TTL	CMOS
Designation 74 means industrial range of 0 to +70 Celsius degrees 54 means military range of -55 to +125 Celsius degrees	Have members in both categories	Have members in both categories
Speed The speed is measured as the propagation delay of the NAND Gate	Very fast, up to 3 [ns]	Fairly fast at 25 ns and lower.
Power Dissipation This is the amount of power in [mW] the IC takes from the power supply	They do take more power, but not very much: 1..19 [mW]	Very little power consumption at low frequencies, but it increases greatly at high frequencies.
Cost	Because they were built long time ago, TTLs are the cheapest of all standard Logic ICs	Fairly low, and they become permanently cheaper. However, some highly specialized ICs could be very expensive.
Fanout This is the number of loads a Logic IC may supply. However, this term is related to the same family. When you relate to inter-families of ICs, you need to check the output current supplied--this data is available in DS	Very good drivers; they do supply the largest amount of output current. Fanout is appx 10 TTL.	Has the largest fanout in its family due to their high input impedance. The inter-families output current supplied, however, is very small (1..2 TTL). Fanout is over 25 CMOS.
Availability	They are available, but mostly as older models. New models are developed almost exclusively for the CMOS type.	Catching up, each day. In addition this is the type that is developed most.
DC voltage supply	5 [V]	3..15 [V]
HIGH logic DC LOW logic DC	3..5 [V] 0.2 [V]	1.7..15 [V] 0 [V]
Size	Mostly DIP packages	Smallest. Many come as SM (Surface Mount) components.

STANDARD LOGIC ICs

There are many standard ICs. Following are presented just few of the most interesting, but you should study this subject seriously.

STANDARD LOGIC ICs
Family number	Description
7406	Hex Inverter, buffer driver.
7414	Hex Schmitt-Trigger.
7426	Dual TTL-CMOS Interface gate
7430	8 Input NAND Gate
7441/7442	BCD to Decimal Decoder
7444	3 Grey code to Decimal Decoder
7446	BCD to Seven-Segments Decimal driver (up to 30 V out)
7470	Edge triggered J-K Flip-Flop
7473	Dual J-K
7475	Quad D
7477	4 bit Bistable latch
7480	Gated Full Adder
7481	16 bit active element memory
7483	4 bit binary Full Adder
7486	Quad XOR Gate
7488	256 bit ROM
7490	Decade Counter
7491	8 bit RAM
7492	Divide by 12 Counter
7497	Synchronous 6-bit Binary rate multiplier
74100	4-bit Bistable Latch
74120	Dual pulse Synchronizer/Driver
74121	Monostable Multivibrator
74123	TTL/Monostable Multivibrator
74126	Tri-State Quad buffer
74128	50 ohms Line Driver
74123	Quad Schmitt Trigger
74133	13-Inputs NAND Gate
74138	3-to-8 Line Decoder/Demultiplexer
74147	Decimal-to-binary Encoder
74151	Eight channel Digital Multiplexer
74156	Dual 2:4 Demultiplexer
74164	8-bit Serial-In Parallel-Out Shift Register
74165	8-bit Parallel-In Serial-Out Shift Register
74167	Rate multiplier
74172	Register File
74181	Arithmetic Logic Unit
74183	Dual Carry-Save Full Address
74188	256-Bit PROM
74190	Up-Down Decade Counter
74200	256-bit RAM

The advantage of using standard logic ICs is, they simplify your work a lot, and they come with very low prices. LEARN HARDWARE FIRMWARE AND SOFTWARE DESIGN presents few excellent applications of standard, logic ICs hardware and firmware implementations. For example, the SPI BUS, Multiplexing, Seven-Segments display, SIPO, PISO, RS232 communications, etc.

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