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

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The output value is 0, which means no current. Regardless of the family used, just be sure to provide by-pass next to the IC.

A bus can only read one data input from a device at one time, and that is when a tri-state buffer is applied. Retrieved from ” https: Data input is active but control input is inactive.

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. Although we allow the data transmission by turning on the control input, we don’t have data coming in because of the infinite resistance.

As a result, huge amounts of power is drawn by the power source, which causes high disturbances. The location of the bypass capacitor is extremely important; read more on Capacitor Placementas it applies to IC by-passing.

The point of this list is to indicate that a government agency could attempt to procure these items based on the VID number provided. Graphically, it is often represented as a triangle with a small circle attaching to the tip. The suffix is used to define the package style [which is listed] and the packaging method during shipping [which is a don’t care].

Because the output current is generated by the voltage source via buffer, the buffer acts as a barrier between the source and load, thus preventing the load resistance affecting the source network.


This kind of buffer performs no inversion or decision-making possibilities. As a result, the power source will not be affected. Note that 54xx devices are listed to the left and only the 74xx devices are listed above. Using just the standard.

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. By using this site, you agree to the Terms of Use and Privacy Policy.

Because the resistance is infinity, the circuit will draw very little current, and will not disturb the original circuit.

If the input is high, the output is low and vice versa. Note the part number suffix is omitted. The output value will be “Z”, the impedance is approaching infinity. So the outputs could be taken tri-state if required.

Buffers: vs – Geek went Freak!

The output value will be 1 and current will flow through the element. It reads an input and outputs a value. From Wikipedia, the free encyclopedia. Data input is nothing but control input is active. 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.

Although one may cost more that the other, but a small price to pay for time to market. The type 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]. 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” pins.

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.


A Tri-state buffer, with its control input, can prevent a bus from reading excessive input. A voltage buffer has a very high input impedance the opposition to current flow viewed from the load.

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

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. It draws very little current and will not disturb the original circuit. Both the bufer and the control input are inactive; the buffer shuts down. Pick a series [54x] if need the temperature range, otherwise use the series [74x].

Note that the chip displayed indicates OE control of the output [Output Enable]. A circuit with a voltage buffer will always draw a little amount of current because of the high input impedance of the buffer.

Digital buffer

That’s what can be delivered faster, or has a lower lead time, or faster deck date. These buffers are normally available in 7424 number of package styles; however only the surface mount PSOP is shown.

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. Both data input and control input is active.

Buffers: 74244 vs 74245

In this case, the input data is sent to the output. The high input impedance is the reason a voltage buffer is used. Tri-state voltage buffers are used widely on buseswhich allows multiple devices communicate with each other.