• Fast read access time – 45ns
• Low-power CMOS operation
– 100µA max standby
– 20mA max active at 5MHz
• JEDEC standard packages
– 28-lead PDIP
– 32-lead PLCC
• 5V±10% supply
• High reliability CMOS technology
– 2,000V ESD protection
– 200mA latchup immunity
• Rapid programming algorithm – 100µs/byte (typical)
• CMOS- and TTL-compatible inputs and outputs
• Integrated product identification code
• Industrial and automotive temperature ranges
• Green (Pb/halide-free) packaging option
256K (32K x 8)
The Atmel® AT27C256R is a low-power, high-performance, 262,144-bit, one-time pro-
grammable, 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 micropro-
The Atmel scaled CMOS technology provides low active power consumption and fast pro-
gramming. Power consumption is typically only 8mA in active mode and less than 10µA in
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 guar-
antees 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 pro-
gramming algorithms and voltages.