Epoxy plastic PDIP packages were often used for commerical temperature range components, while ceramic packages CDIP were used for military temperature range parts. Email Required, but never shown. It is driven by applying the same current steering idea as above. While originally designed to handle logic-level digital signals, a TTL inverter can be biased as an analog amplifier. A common variation omits the collector resistor of the output transistor, making an open-collector output. Such amplifiers may be useful to convert analog signals to the digital domain but would not ordinarily be used where analog amplification is the primary purpose. If individually packaged transistors were used, the cost of all the transistors would discourage one from using such an input structure.
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Examples of this type of gate are the  and series. Harvard University faculty web page. Home Htl Tags Users Unanswered. Views Read Edit View history. When all the inputs are held at high voltage, the base—emitter junctions of the multiple-emitter transistor are reverse-biased. This allows the designer to fabricate logic by connecting the open-collector outputs of several logic gates together and providing a single external pull-up resistor.
Not only did others make compatible TTL parts, but compatible parts were made using many other circuit technologies as well. Open-collector outputs of some gates have a higher maximum voltage, such as 15V for the useful when driving other than TTL loads. My company is building a device that is specified to have TTL outputs and I shall test them.
Static Dynamic Domino logic Four-phase logic.
Designers can combine ECL and TTL devices in the same system to achieve best overall performance and economy, but level-shifting devices are required between the two logic families. The true origins of the personal computer” Archived at the Wayback Machine. The resistor R 3 does not increase the output resistance since it is connected in the V 3 collector and its influence is compensated by the negative feedback.
To solve the problem with the high output resistance of the simple output stage the second schematic adds to this a “totem-pole” ” push—pull ” output. Even after Very-large-scale integration integrated circuits made multiple-circuit-board processors obsolete, TTL devices still found extensive use as the glue logic interfacing between more densely integrated components. It pulls up the V 5 cathode and cuts-off the diode.
Transistor–transistor logic – Wikipedia
If such an analog input must be used, there are specialized TTL parts with Schmitt trigger inputs available that will reliably convert the analog input to a digital value, effectively operating as a one bit A to D converter. A slowly changing input like this can also cause excess power dissipation in the output circuit. A common variation omits the collector resistor of the output transistor, making an open-collector output. Successive generations of technology produced compatible parts with improved power consumption or switching speed, or both.
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The output can be erratic when the input is in this range. The Texas Instruments family became an industry standard.
These pulses can couple in unexpected ways between multiple integrated circuit packages, resulting in reduced noise margin and lower performance. Radiation-hardened devices for example from the SNJ54 series are offered for space applications. In some cases e.
The driving stage must absorb up to 1. As microprocessors became more functional, TTL devices became important for “glue logic” applications, such as fast bus drivers on a motherboard, which tie together the function blocks realized in VLSI elements. Its name signifies that transistors perform both the logic function the first “transistor” and the amplifying function the second “transistor” ; it is the same naming convention used in resistor—transistor logic RTL and diode—transistor logic DTL.
This is because the transistor is in reverse-active mode.
Parts for military and aerospace applications were packaged in flatpacksa form of surface-mount package, with leads suitable for welding or soldering to printed circuit boards. The main advantage of TTL with a “totem-pole” output stage is the low output resistance at output logical “1”.
Thomas Weller 3 Such amplifiers may be useful to convert analog signals to lvftl digital domain but would not ordinarily be used where analog amplification is the primary purpose.