Search results
Results from the WOW.Com Content Network
Often two level shifters are used, one at each system: A line driver converts from internal logic levels to standard interface line levels; a line receiver converts from interface levels to internal voltage levels. For example, TTL levels are different from those of CMOS. Generally, a TTL output does not rise high enough to be reliably ...
Transistor–transistor logic (TTL) is a logic family built from bipolar junction transistors.Its name signifies that transistors perform both the logic function (the first "transistor") and the amplifying function (the second "transistor"), as opposed to earlier resistor–transistor logic (RTL) and diode–transistor logic (DTL).
This problem was solved by the invention of the 74HCT family of devices that uses CMOS technology but TTL input logic levels. These devices only work with a 5V power supply. They form a replacement for TTL, although HCT is slower than original TTL (HC logic has about the same speed as original TTL).
In digital electronics, a level shifter, also called level converter or logic level shifter, or voltage level translator, is a circuit used to translate signals from one logic level or voltage domain to another, allowing compatibility between integrated circuits with different voltage requirements, such as TTL and CMOS.
As semiconductor technology has progressed, LVCMOS power supply voltage and interface standards for decreasing voltages have been defined by the Joint Electron Device Engineering Council for digital logic levels lower than 5 volts.
A five level PAM digital signal. In digital electronics, a digital signal is a pulse amplitude modulated signal, i.e. a sequence of fixed-width electrical pulses or light pulses, each occupying one of a discrete number of levels of amplitude. [6] [7] A special case is a logic signal or a binary signal, which varies between a low and a high ...
Normal TTL signals are single-ended, which means that each signal consists of a voltage on one wire, referenced to a system ground. [3] The "low" voltage level is zero to 0.8 volts, and the "high" voltage level is 2 volts to 5 volts. A differential TTL signal consists of two such wires, also referenced to a system ground.
Although the 7400 series was the first de facto industry standard TTL logic family (i.e. second-sourced by several semiconductor companies), there were earlier TTL logic families such as: Sylvania Universal High-level Logic in 1963 [8] [9] [10] Motorola MC4000 MTTL [11] [12] [13] National Semiconductor DM8000 [14] [better source needed]