Description
The ’HC670 and CD74HCT670 are 16-bit register files organized as 4 words x 4 bits each. Read and write address and enable inputs allow simultaneous writing into one location while reading another. Four data inputs are provided to store the 4-bit word. The write address inputs (WA0 and WA1) determine the location of the stored word in the register.

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 = 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