The CD74HCT259E from Texas Instruments is a high-speed SMOS logic 8-bit addressable latch, which is part of the CDx4HC(T)259 family. This integrated circuit (IC) is designed to offer buffered inputs and outputs, and it supports four distinct operating modes, including three active modes (addressable latch, memory, 8-line demultiplexer) and one reset mode. A notable feature of this device is its typical propagation delay of 15ns at a supply voltage (VCC) of 5V, with a load capacitance (CL) of 15pF and an ambient temperature (TA) of 25°C.
The CD74HCT259E is characterized by its wide operating temperature range of -55°C to 125°C, making it suitable for demanding environments. It also offers significant power reduction compared to LSTTL logic ICs. For applications requiring direct compatibility with LSTTL input logic, the HCT types within this family, including the CD74HCT259E, operate within a 4.5V to 5.5V range, providing ease of integration into existing systems. The device's balanced propagation delay and transition times are key in maintaining signal integrity in complex digital logic circuits.
Digital Logic ICs
Addressable latches, such as the CD74HCT259E, are digital logic components used to store and manage digital signals within a circuit. They are capable of holding data in a stable state until it is required for further processing, making them essential in digital memory and data storage systems. Addressable latches are distinguished by their ability to selectively write or read data to or from specific locations within the device, facilitated by addressing inputs.
When selecting an addressable latch, engineers should consider the device's operating modes, propagation delay, operating temperature range, and compatibility with existing logic levels. The propagation delay is particularly important in high-speed applications, as it determines how quickly the device can respond to input signals. The operating temperature range indicates the environmental conditions under which the device can reliably operate, which is critical for applications subject to extreme conditions.
Furthermore, compatibility with LSTTL and CMOS logic levels ensures that the addressable latch can be easily integrated into a wide range of digital systems without requiring additional interfacing components. The fanout capability, indicating how many standard LSTTL loads the device can drive, is also an important consideration for ensuring adequate signal strength across the system.
In summary, addressable latches like the CD74HCT259E play a crucial role in digital systems, offering flexibility in data management and signal routing. Their selection and integration into circuits require careful consideration of their technical specifications and compatibility with the system's overall design requirements.