The 74HC; 74HCT is an 8-bit buffer/line driver with 3-state outputs. The device can be used as two 4-bit buffers or one 8-bit buffer. Buffers: vs is an octal unidirectional buffer. The 8 lines can be split into two groups and each group can be individually. Electrical Engineering Glossary of Electronic Terms, 8-Bit Buffer IC, functional schematic diagram, true table and package out-line. 74HCT

Author: Zulushura Samuktilar
Country: Cambodia
Language: English (Spanish)
Genre: Video
Published (Last): 1 July 2007
Pages: 223
PDF File Size: 13.47 Mb
ePub File Size: 16.53 Mb
ISBN: 675-5-20822-291-1
Downloads: 48974
Price: Free* [*Free Regsitration Required]
Uploader: Vunris

The location of the bypass capacitor is extremely important; read more on Capacitor Placementas it applies to IC by-passing.

This page was last edited on 19 Septemberat Note that 54xx devices are listed to the left and only the 74xx devices are listed above. It reads an input and buffr a value. Also refer to Logic Family vs Switching Speed.

The output value will be high if and only if the input value is high.

The output value is 0, which means no current. Because the output current is generated by the voltage source via buffer, the buffer 744244 as a barrier between the source and load, thus preventing the load resistance affecting the source network.

Digital buffer – Wikipedia

So the outputs could be taken tri-state if required. A control input is analogous to a valve, which controls the data flow. The output value will be “Z”, the impedance is approaching infinity.

Although we allow the data transmission by turning on bbuffer control input, we don’t have data coming in because of the infinite resistance. If we have a power source and a low impedance resistor load without 7424 buffer, according to Ohm’s law voltage is equal to current times resistancea huge amount of current is drawn from the source.

Tri-state voltage buffers are used widely on buseswhich allows multiple devices communicate with each other. A bus can only read bbuffer data input from a device at one time, and that is when a tri-state buffer is applied.

A typical digital buffer that is used to control multiple data inputs written onto a bus is a Tri-State Digital Buffer, which controls the data flow by “tri-state” buffeer. Regardless of the family used, just be sure to provide by-pass next to the IC.


Buffers: 74244 vs 74245

Both data input and control input is active. When the control input is active, the output value is the input value, and the buffer is not different from the single input digital buffer.

That’s what can be delivered faster, or has a lower lead time, or faster deck date. This kind of buffer performs no inversion or decision-making possibilities. The bjffer or family of buffer used does make a difference in the table above, just the trailing digits that indicate the type of buffer [as in the different options].

However what is available in the IC family may also come into play. A voltage buffer always has a very high input impedance, approaching infinity; as a result, no matter what value the load impedance is, the source voltage will be totally spanned on the buffer impedance because of Ohm’s law ; the voltage across the buffer impedance is the input voltage.

Finally, note that the manufacturer is not listed here either. The functional IC is split into two 4-bit sections, so they could be operated together or separately, driving one 8-bit bus or two separate 4-bit buses.

It is basically the same as active high digital buffer buffdr the fact that the buffer is active when the control input is at a low state.

Because the resistance is infinity, the circuit will draw very little current, and will not disturb the original circuit. The suffix is used to define the package style [which is listed] and the packaging method during shipping [which is a don’t care].

Both the data and the control input are inactive; the buffer shuts down. If the input is high, the output is low and vice versa. It is also called a unity gain buffer because it provides a gain of 1, which means it provides at most the same voltage as the input voltage, serving no amplification function. The high input impedance is the reason a voltage buffer is used. Data input is nothing but control input is active. A single input digital buffer is different from an inverter.

A digital buffer serves to transfer a voltage from a circuit that has a high output impedance level, to a second circuit with a low input impedance level. A digital buffer or a voltage buffer is an electronic circuit element that is used to isolate the input from the output, providing either no voltage or a voltage that is same as the input voltage. The output value will be 1 and current will flow through the element.


These buffers are normally available in a number of package styles; however only the surface mount PSOP is shown. Other than size, Lead Inductance is the next important issue because it slows down switching time, while the size of the IC package causes the placement of the capacitor to move away from the power leads of the IC.

Pick a series [54x] if need the temperature range, otherwise use the series [74x]. Although one may cost more that the other, but a small price to pay for time to market.

The point of this list is to indicate that a government agency could attempt to procure these items based on the VID number provided. As a result, the power source will not be affected. Using just the standard. Add a second by-pass capacitor, and place both by-pass capacitors as close to the Vcc line as possible.

From Wikipedia, the free encyclopedia. It does not invert or alter its input signal in any way. Design Hint; Because this chip is used to drive a bus, which may be capacitive loaded, use more than the normal by-pass capacitor to insure that the IC has the current it needs when the buffers begin to drive the bus. In this case, the input burfer is sent to the output.

Glossary of Electronic and Engineering Terms, IC 8-Bit Buffer Description

As a result, huge amounts 774244 power is drawn by the power source, which causes high disturbances. Views Read Edit View history. Decoders, state machines, and other sophisticated digital devices may use inverters. When the data input is nothing and the control input is open, the output value will be “Z”, which means no current and high impedance.