This post explains for the TTL Memory.
The Part Number is 74LS189.
The function of this semiconductor is 64-BIT RANDOM ACCESS MEMORY
The Package: DIP 16 Pin type
Manufacturer: TI, Fairchild
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The 74LS189 is a high speed 64-bit RAM orgainized as a 16-word by 4-bit array. Address inputs are buffered to minimize loading and are fully decoded on-chip. The outputs are 3-state and are in the high impedance state whenever the Chip select (CS) input is HIGH. The outputs are active only in the Read mode and the output data is the complement of the stored data.
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Features
1. 3-State Ouputs For Data BUS Applications
2. Buffered Inputs Minimize Loading
3. Address Decoding ON-Chip
4. Diode Clamped Inputs Minimize Ringing
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74LS189 Datasheet
