M27C256B-90B6

Memory IC Overview

The M27C256B-90B6 is a 256 Kbit (32Kb x 8) UV EPROM and OTP EPROM manufactured by STMicroelectronics. It operates with a 5V ± 10% supply voltage in read mode and features a 90 ns access time. The device requires a 12.75V program supply voltage for programming operations, which take 100 µs per word. It supports parallel interface communication and is available in PDIP28 packages for non-erasable applications.

Memory IC Feature Summary

• Supports both UV erasable and one-time programmable configurations
• Features two-line control function to minimize power dissipation and prevent output bus contention
• Includes electronic signature capability for automatic identification by programming equipment
• Utilizes PRESTO II programming algorithm for efficient array programming

Memory IC Applications

• Microprocessor systems requiring firmware storage
• Memory arrays utilizing two-line control functions
• Applications necessitating electronic signature verification during programming

Memory IC Procurement Notes

Verify the specific package variant against project requirements, as the M27C256B family includes FDIP28W, PLCC32, and TSOP28 options alongside the PDIP28. Confirm that the ordering suffix corresponds to the desired speed grade and temperature range. Ensure compatibility with existing programming hardware regarding the required 12.75V supply and TTL input levels. Check for end-of-life status or alternative sourcing needs due to component age.

Memory IC Selection Notes

Select this component when a 256 Kbit capacity with 90 ns access speed is required for microprocessor memory systems. Choose the UV version if field reprogramming via ultraviolet light is necessary, otherwise select the OTP variant for permanent data storage. Ensure the design accommodates the 12.75V programming voltage and provides adequate decoupling capacitors to manage transient current peaks during operation.

Memory IC Part Context

The M27C256B belongs to the M27 series of high-speed CMOS EPROMs from STMicroelectronics. This family offers various speed grades ranging from 45 ns to 250 ns and multiple package types including ceramic DIP with windows for UV erase and plastic packages for OTP use. The device integrates standard EPROM functionality with advanced control features suitable for complex memory architectures.

Memory IC Replacement Considerations

M27C256B-45B6, M27C256B-60B6, M27C256B-70B6, M27C256B-80B6, M27C256B-10B6, M27C256B-12B6, M27C256B-15B6, M27C256B-20B6, M27C256B-25B6