The DM74S188N is a 256-Bit (32 x 8) Programmable Read-Only Memory (PROM) manufactured by National Semiconductor (now Texas Instruments). This memory device allows users to store and retrieve data permanently. Once programmed, the data cannot be erased, making it suitable for storing firmware, look-up tables, and other fixed data in digital systems.

Applications

• Microcontroller firmware storage
• Look-up tables
• Character generators
• Code converters
• Sequence generators

Features

• 256-Bit (32 x 8) Memory: Stores 32 bytes of data.
• Programmable: Data can be written once by blowing fuses.
• Fast Access Time: Provides quick access to stored data.
• TTL Logic: Compatible with other TTL devices.
• DIP Package: Easy to use with breadboards and prototyping boards.

Benefits

• Permanent Data Storage: Ensures data retention even when power is removed.
• Fast Data Retrieval: Provides quick access to stored data, improving system performance.
• Easy Programming: Simple to program using commercially available PROM programmers.
• Reliable Operation: Offers stable performance in various environments.
• Simple Implementation: Simplifies the design of digital systems requiring permanent data storage.

Additional Details

The DM74S188N is typically programmed by selectively blowing fuses within the memory array using a PROM programmer. The device has address inputs to select one of the 32 memory locations and output pins to provide the 8-bit data stored at the selected location. The access time is a critical specification, indicating how quickly data can be read from the memory after an address is applied. The supply voltage is typically 5V. The package is a 16-pin DIP (Dual In-line Package). Like other parts from this era, the DM74S188N is considered END-OF-LIFE, and sourcing may be difficult.