Description

The CD74HCT646E is a 16-bit register file designed with simultaneous and independent read and write operations. It is organized as 4 words x 4 bits, with four data inputs for storing a 4-bit word. The write address inputs determine the location of the stored word in the register.

Specifications and Features

• Simultaneous and independent read and write operations
• Expandable to 512 words of n-bits
• Three-state outputs
• Organized as 4 words x 4 bits wide
• Buffered inputs
• Typical read time of 16ns for 'HC670 VCC = 5V, CL = 15pF, TA = 25°C
• Fanout (Over Temperature Range):
  • Standard outputs: 10 LSTTL loads
  • Bus driver outputs: 15 LSTTL loads
• Wide operating temperature range: -55oC to 125oC
• Balanced propagation delay and transition times
• Significant power reduction compared to LSTTL logic ICs
• HC Types:
  • 2V to 6V operation
  • High noise immunity: NIL = 30%, NIH = 30% of VCC at VCC = 5V
• HCT Types:
  • 4.5V to 5.5V operation
  • Direct LSTTL input logic compatibility: VIL= 0.8V (Max), VIH = 2V (Min)
  • CMOS input compatibility: Il ≤ 1µA at VOL, VOH

Application Scenarios

The CD74HCT646E can be used in various applications that require simultaneous read and write operations, such as memory registers, data storage systems, and parallel processing units. Its wide operating temperature range makes it suitable for both industrial and automotive applications.

Comparison

• Simultaneous and independent read and write operations
• Expandable to 512 words of n-bits
• Wide operating temperature range
• Significant power reduction compared to LSTTL logic ICs

• Higher noise immunity compared to some other logic ICs