Transistor-transistor logic - Revision history

Jnc: /* Operation */ +link

2022-04-24T01:59:39Z

Operation: +link

← Older revision		Revision as of 01:59, 24 April 2022
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	==Operation==		==Operation==

	In TTL, gates produce low outputs by sinking [[current]] to [[ground]] (drawing it ''into'' the gate through the output, seemingly paradoxically): the [[transistor\|collector]] of the gate's output transistor is connected to the gate's output, and the [[transistor\|emitter]] to ground, and when the gate is on, for a low output, current flows through the transistor to ground. When the gate is off, the output is pulled up via a [[resistor]] connected to the supply voltage.		In TTL, gates produce low outputs by sinking [[current]] to [[ground]] (drawing it ''into'' the gate through the output, seemingly paradoxically): the [[transistor\|collector]] of the gate's output transistor is connected to the gate's output, and the [[transistor\|emitter]] to ground, and when the gate is on, for a low output, current flows through the transistor to ground. When the gate is off, the output is pulled up via a [[resistor]] connected to the supply [[voltage]].

	Use of a smaller pull-up resistor results in a gate which can switch faster, but draws more power; similarly a larger one produces a transistor that is slower, but uses less power. These approaches are used in the 74H and 74L TTL families, respectively.		Use of a smaller pull-up resistor results in a gate which can switch faster, but draws more power; similarly a larger one produces a transistor that is slower, but uses less power. These approaches are used in the 74H and 74L TTL families, respectively.

Jnc: /* Operation */ clarify

2022-04-24T01:58:41Z

Operation: clarify

← Older revision		Revision as of 01:58, 24 April 2022
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	==Operation==		==Operation==

	In TTL, gates produce low outputs by sinking [[current]] to [[ground]] (drawing it ''into'' the gate through the output, seemingly paradoxically): the [[transistor\|collector]] of the gate's output transistor is connected to the gate's output, and the [[transistor\|emitter]] to ground, and when the gate is on, current flows through the transistor to ground. When the gate is off, the output is pulled up via a [[resistor]] connected to the supply voltage.		In TTL, gates produce low outputs by sinking [[current]] to [[ground]] (drawing it ''into'' the gate through the output, seemingly paradoxically): the [[transistor\|collector]] of the gate's output transistor is connected to the gate's output, and the [[transistor\|emitter]] to ground, and when the gate is on, for a low output, current flows through the transistor to ground. When the gate is off, the output is pulled up via a [[resistor]] connected to the supply voltage.

	Use of a smaller pull-up resistor results in a gate which can switch faster, but draws more power; similarly a larger one produces a transistor that is slower, but uses less power. These approaches are used in the 74H and 74L TTL families, respectively.		Use of a smaller pull-up resistor results in a gate which can switch faster, but draws more power; similarly a larger one produces a transistor that is slower, but uses less power. These approaches are used in the 74H and 74L TTL families, respectively.

Jnc: +See also

2021-10-14T18:19:19Z

+See also

← Older revision		Revision as of 18:19, 14 October 2021
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	Most computers from the late 1960s through to the middle 1970s were produced entirely in TTL (although its use in such ways continued until the early 1980s - e.g. the [[IBM 3081]] was built out of TTL), and TTL continued to be widely used for the 'glue' logic between larger [[VLSI]] chips until the 1990s, when the lower voltages used with most [[CMOS]] made them obsolete.		Most computers from the late 1960s through to the middle 1970s were produced entirely in TTL (although its use in such ways continued until the early 1980s - e.g. the [[IBM 3081]] was built out of TTL), and TTL continued to be widely used for the 'glue' logic between larger [[VLSI]] chips until the 1990s, when the lower voltages used with most [[CMOS]] made them obsolete.

			==See also==

			* [[emitter-coupled logic\|ECL]]

	==External links==		==External links==

Jnc: +cat

2018-12-14T18:20:32Z

+cat

← Older revision		Revision as of 18:20, 14 December 2018
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	* [http://en.wikipedia.org/wiki/Transistor–transistor_logic TTL article on Wikipedia] - has comprehensive coverage of the topic		* [http://en.wikipedia.org/wiki/Transistor–transistor_logic TTL article on Wikipedia] - has comprehensive coverage of the topic

			[[Category: Technology‎]]

Jnc: +link

2018-10-14T12:01:51Z

+link

← Older revision		Revision as of 12:01, 14 October 2018
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	'''Transistor-transistor logic''' (usually referred to by its acronym, '''TTL''') is a [[logic]] ~~[[circuit]] family~~ which replaced the earlier [[diode-transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].		'''Transistor-transistor logic''' (usually referred to by its acronym, '''TTL''') is a [[logic family]] which replaced the earlier [[diode-transistor logic]]. It is the [[circuit]] type inside the most widespread early [[integrated circuit]] [[logic]] family, the [[74 series]].

	The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.		The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.

Jnc: Effing N-dashes!!!!

2018-09-14T19:41:39Z

Effing N-dashes!!!!

← Older revision		Revision as of 19:41, 14 September 2018
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	'''Transistor-transistor logic''' (usually referred to by its acronym, '''TTL''') is a [[logic]] [[circuit]] family which replaced the earlier [[~~diode–transistor~~ logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].		'''Transistor-transistor logic''' (usually referred to by its acronym, '''TTL''') is a [[logic]] [[circuit]] family which replaced the earlier [[diode-transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].

	The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.		The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.

Jnc: Mention common acronym

2018-09-14T19:40:18Z

Mention common acronym

← Older revision		Revision as of 19:40, 14 September 2018
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	'''Transistor-transistor logic''' is a [[logic]] [[circuit]] family which replaced the earlier [[diode–transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].		'''Transistor-transistor logic''' (usually referred to by its acronym, '''TTL''') is a [[logic]] [[circuit]] family which replaced the earlier [[diode–transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].

	The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.		The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.

Jnc: Fix ext link

2018-09-14T19:10:43Z

Fix ext link

← Older revision		Revision as of 19:10, 14 September 2018
Line 1:		Line 1:
	'''Transistor-transistor logic''' is a [[logic]] circuit family which replaced the earlier [[diode–transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].		'''Transistor-transistor logic''' is a [[logic]] [[circuit]] family which replaced the earlier [[diode–transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].

	The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.		The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.
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	==External links==		==External links==

	* [http://en.wikipedia.org/wiki/Transistor–transistor_logic ~~Transistor–transistor logic~~ TTL article on Wikipedia - has comprehensive coverage of the topic]		* [http://en.wikipedia.org/wiki/Transistor–transistor_logic TTL article on Wikipedia] - has comprehensive coverage of the topic

Jnc: 74 series not as important as overall concept

2018-09-14T19:01:28Z

74 series not as important as overall concept

← Older revision		Revision as of 19:01, 14 September 2018
Line 1:		Line 1:
	'''Transistor-transistor logic''' is the circuit type inside the most widespread early [[integrated circuit]] family, the [[74 series~~]]; it replaced the earlier [[diode–transistor logic~~]].		'''Transistor-transistor logic''' is a [[logic]] circuit family which replaced the earlier [[diode–transistor logic]]. It is the circuit type inside the most widespread early [[integrated circuit]] logic family, the [[74 series]].

	The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.		The name is derived from the fact that both logic as well as signal-amplification were performed by [[transistor]]s; also, most [[gate]]s are composed of one or more transistors.

Jnc: Clarifications

2018-04-23T03:06:09Z

Clarifications

← Older revision		Revision as of 03:06, 23 April 2018
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	==Operation==		==Operation==

	In TTL, gates produce low outputs by sinking [[current]] to ground (drawing it in through the output, seemingly paradoxically): the [[transistor\|collector]] of the gate's output transistor is connected to the gate's output, and the [[transistor\|emitter]] to ground, and when the gate is on, current flows through the transistor to ground. When the gate is off, the output is pulled up via a [[resistor]] connected to the supply voltage.		In TTL, gates produce low outputs by sinking [[current]] to [[ground]] (drawing it ''into'' the gate through the output, seemingly paradoxically): the [[transistor\|collector]] of the gate's output transistor is connected to the gate's output, and the [[transistor\|emitter]] to ground, and when the gate is on, current flows through the transistor to ground. When the gate is off, the output is pulled up via a [[resistor]] connected to the supply voltage.

	Use of a smaller pull-up resistor results in a gate which can switch faster, but draws more power; similarly a larger one produces a transistor that is slower, but uses less power. These approaches are used in the 74H and 74L TTL families, respectively.		Use of a smaller pull-up resistor results in a gate which can switch faster, but draws more power; similarly a larger one produces a transistor that is slower, but uses less power. These approaches are used in the 74H and 74L TTL families, respectively.

	One sub-set of TTL uses a pair of transistors in a so-called 'totem pole' arrangement, with the collector of one attached to the supply voltage, the emitter of the other attached to ground, and the remaining emitter and collector both connected to the output. The two are then driven by the desired logic signal and its negation. This produced a ~~chip~~ which has symmetric high->low and low->high switching.		One sub-set of TTL uses a pair of transistors in a so-called 'totem pole' output arrangement, with the collector of one attached to the supply voltage, the emitter of the other attached to ground, and the remaining emitter and collector are both connected to the output. The two transistors are then driven by the desired logic signal and its negation. This produced a gate which has symmetric high->low and low->high switching.

	Another sub-set of TTL are [[open collector]] gates.		Another sub-set of TTL are [[open collector]] gates.