27C512

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M27C512: 512 Kbit (64K x 8) UV Erasable Programmable Read-Only Memory (EPROM)

Overview

The M27C512 is a high-performance 512 Kbit (64K x 8) UV-erasable programmable read-only memory (EPROM) designed for applications requiring non-volatile storage. This component is fabricated using advanced CMOS technology, providing low power consumption while maintaining high-speed operation. The M27C512 is housed in a transparent windowed ceramic or plastic package, allowing for ultraviolet (UV) light erasure and reprogramming, making it ideal for development and prototyping environments.

Key Features

• High-Density Storage: 512 Kbit organized as 64K x 8 bits.
• Low Power Consumption: CMOS technology ensures efficient operation with active current as low as 30 mA and standby current of 100 µA.
• Fast Access Time: Available in speed grades of 120 ns, 150 ns, and 200 ns, suitable for high-performance systems.
• UV Erasable: Fully erasable with UV light exposure (typically 15-20 minutes under a UV lamp).
• Single +5V Supply: Simplifies system design by operating on a single power supply.
• Tri-State Outputs: Allows for easy bus sharing in microprocessor-based systems.
• Programmable: Supports standard EPROM programming methods with a 12.5V programming voltage.
• Wide Temperature Range: Commercial (0°C to +70°C) and Industrial (-40°C to +85°C) variants available.

Applications

The M27C512 is widely used in embedded systems, firmware storage, and legacy computing applications, including:

• Microcontroller-based systems requiring non-volatile code storage.
• Industrial control systems and automation.
• Legacy computing and retro computing applications.
• Firmware development and prototyping.
• Telecommunications equipment.
• Automotive electronics (where UV reprogrammability is advantageous).

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (V_CC): -0.5V to +7.0V
• Programming Voltage (V_PP): -0.5V to +13.5V
• Input Voltage (V_IN): -0.5V to V_CC + 0.5V
• Operating Temperature Range: Commercial (0°C to +70°C) / Industrial (-40°C to +85°C)
• Storage Temperature: -65°C to +150°C

DC Characteristics (V_CC = 5V ±10%, T_A = 25°C)

• Input High Voltage (V_IH): 2.0V min
• Input Low Voltage (V_IL): 0.8V max
• Output High Voltage (V_OH): 2.4V min (I_OH = -2.0 mA)
• Output Low Voltage (V_OL): 0.4V max (I_OL = 2.0 mA)
• Standby Current (I_SB): 100 µA max
• Active Current (I_CC): 30 mA max (at 5 MHz)

AC Characteristics

• Address Access Time (t_ACC): 120 ns / 150 ns / 200 ns (speed grade dependent)
• Chip Enable Access Time (t_CE): 120 ns / 150 ns / 200 ns
• Output Enable Time (t_OE): 70 ns max
• Read Cycle Time (t_RC): 120 ns / 150 ns / 200 ns

Package Information

The M27C512 is available in multiple package options, including:

• Windowed Ceramic DIP (PDIP): 28-pin (Cerdip) with UV-transparent quartz window for erasure.
• Plastic DIP (PDIP): 28-pin (non-windowed, one-time programmable).
• PLCC (Plastic Leaded Chip Carrier): 32-pin (J-lead) for surface-mount applications.

Pin Configuration (28-Pin DIP)

• Pins A0-A15: Address inputs (64K addressing).
• Pins O0-O7: Data outputs (tri-state).
• CE (Chip Enable): Active-low control for device selection.
• OE (Output Enable): Active-low control for output buffer.
• V_PP: Programming voltage (12.5V during programming).
• V_CC: +5V power supply.
• GND: Ground reference.

Programming and Erasure

The M27C512 supports standard EPROM programming protocols:

• Programming Voltage (V_PP): 12.5V ±5%.
• Programming Algorithm: Byte-by-byte programming with 50 ms pulses per byte.
• UV Erasure: Requires exposure to UV light (2537 Å wavelength) for 15-20 minutes at a distance of 1 inch from a 12,000 µW/cm² UV source.

Conclusion

The M27C512 is a reliable and versatile EPROM solution for applications requiring reprogrammable non-volatile memory. Its combination of high density, low power consumption, and UV erasability makes it suitable for development, legacy systems, and industrial applications. With multiple speed grades and package options, it provides flexibility for various design requirements.

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