The Microchip AT27C256R is a low-power, high-performance, 262,144-bit, one-time programmable, read-only memory (OTP EPROM) organized as 32K by 8 bits. It requires only one 5V power supply in normal read mode operation. Any byte can be accessed in less than 45ns, eliminating the need for speed reducing WAIT states on high-performance microprocessor systems. The Microchip scaled CMOS technology provides low active power consumption and fast programming. Power consumption is typically only 8mA in active mode and less than 10µA in standby mode. The AT27C256R is available in a choice of industry-standard, JEDEC-approved, one-time programmable (OTP) PDIP and PLCC packages. All devices feature two-line control (CE, OE) to give designers the flexibility to prevent bus contention. With 32K byte storage capability, the AT27C256R allows firmware to be stored reliably and to be accessed by the system without the delays of mass storage media. The AT27C256R has additional features to ensure high quality and efficient production use. The rapid programming algorithm reduces the time required to program the part and guarantees reliable programming. Programming time is typically only 100µs/byte. The integrated product identification code electronically identifies the device and manufacturer. This feature is used by industry-standard programming equipment to select the proper programming algorithms and voltages.