74HC640DB,118

The 74HC640DB,118 is a monolithic integrated circuit composed of two 4-input NAND gates, two D-type flip-flops and two buffers. It belongs to the Logic - Buffers, Drivers, Receivers, Transceivers family.

Application Fields

The 74HC640DB,118 is a versatile logic gate applied to many types of applications, like Display systems such as LED and LCD drivers, Proximity and infrared sensors, data acquisition systems, logic gates, multiplexer/demultiplexers, interface design, etc.

Working Principle

The 74HC640DB,118 comprises of two 4-input NAND gates, two D-type flip-flops and two buffers. The 4-input NAND gate is a logic gate containing four logic inputs. The logic outputs will be low when any combination of inputs is high. The D-type flip-flop is a combination of two NAND gates and one OR gate, which delay the incoming signal. The two buffers serve as two independent two-terminal devices, which provide buffering and invert or non-invert the input signal. The inputs and outputs of the flip-flops and the NAND gates are TTL compatible.

The 74HC640DB,118 is typically used to convert serial logic data from and to parallel logic data, or to realize bidirectional shift registers. The 74HC640DB,118 device can also be used for level shifting and interfacing two buses of different logic levels, for example TTL and CMOS. When used as a level shifter, the 74HC640DB,118 can provide up to 20mA of output sink current and up to 4mA of output source current.