Gunning transceiver logic (GTL) is a type of logic signaling used to drive electronic

backplane A backplane or backplane system is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used to connect s ...

buses A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used ...

. It has a

voltage Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...

swing between 0.4 volts and 1.2 volts — much lower than that used in TTL and

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss ", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...

logic — and symmetrical parallel resistive termination. The maximum signaling

frequency Frequency is the number of occurrences of a repeating event per unit of time. Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio ...

is specified to be 100 MHz, although some applications use higher frequencies. GTL is defined by

JEDEC The Joint Electron Device Engineering Council (JEDEC) Solid State Technology Association is a consortium of the semiconductor industry headquartered in Arlington County, Virginia, Arlington, United States. It has over 300 members and is focused ...

standard JESD 8-3 (1993) and was invented by William Gunning while working for

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at the Palo Alto Research Center. All Intel

front-side bus The front-side bus (FSB) is a computer communication interface ( bus) that was often used in Intel-chip-based computers during the 1990s and 2000s. The EV6 bus served the same function for competing AMD CPUs. Both typically carry data between th ...

es use GTL. As of 2008, GTL in these FSBs has a maximum frequency of 1.6 GHz. The front-side bus of the Intel Pentium Pro,

Pentium II The Pentium II is a brand of sixth-generation Intel x86 microprocessors based on the P6 (microarchitecture), P6 microarchitecture, introduced on May 7, 1997. It combined the ''P6'' microarchitecture seen on the Pentium Pro with the MMX (instruc ...

and

Pentium III The Pentium III (marketed as Intel Pentium III Processor, informally PIII or P3) brand refers to Intel's 32-bit x86 desktop and mobile CPUs based on the sixth-generation P6 (microarchitecture), P6 microarchitecture introduced on February 28, 1999 ...

microprocessors uses GTL+ (or GTLP) developed by

Fairchild Semiconductor Fairchild Semiconductor International, Inc. was an American semiconductor company based in San Jose, California. It was founded in 1957 as a division of Fairchild Camera and Instrument by the " traitorous eight" who defected from Shockley Semi ...

, an upgraded version of GTL which has defined

slew rate In electronics and electromagnetics, slew rate is defined as the change of voltage or current, or any other electrical or electromagnetic quantity, per unit of time. Expressed in SI units, the unit of measurement is given as the change per seco ...

s and higher voltage levels. AGTL+ stands for either assisted Gunning transceiver logic or advanced Gunning transceiver logic. These are GTL signaling derivatives used by Intel microprocessors.

References

* * * * {{Logic Families Computer buses JEDEC standards Logic families