Features Fast read access time 90ns Dual voltage range operation Low voltage power supply range, 3.0V to 3.6V, or Standard power supply range, 5V 10% Compatible with JEDEC standard Atmel AT27C256R Low-power CMOS operation 20A max standby (less than 1A, typical) for V = 3.6V CC 29mW max active at 5MHz for V = 3.6V CC 256K (32K x 8) JEDEC standard package Low Voltage, 32-lead PLCC High-reliability CMOS technology One-time 2,000V ESD protection Programmable, 200mA latchup immunity Read-only Memory Rapid programming algorithm 100s/byte (typical) CMOS- and TTL-compatible inputs and outputs JEDEC standard for LVTTL Atmel AT27LV256A Integrated product identification code Industrial temperature range Green (Pb/halide-free) packaging option 1. Description The Atmel AT27LV256A is a high-performance, low-power, low-voltage, 262,144-bit, one- time programmable, read-only memory (OTP EPROM) organized as 32K by 8 bits. It requires only one supply in the range of 3.0V to 3.6V in normal read mode operation, mak- ing it ideal for fast, portable systems using battery power. The Atmel innovative design techniques provide fast speeds that rival 5V parts, while keep- ing the low power consumption of a 3.3V supply. At V = 3.0V, any byte can be accessed CC in less than 90ns. With a typical power dissipation of only 18mW at 5MHz and V = 3.3V, CC the AT27LV256A consumes less than one-fifth the power of a standard, 5V EPROM. Standby mode supply current is typically less than 1A at 3.3V. The AT27LV256A is available in an industry-standard, JEDEC-approved, one-time program- mable (OTP) PLCC package. All devices feature two-line control (CE, OE) to give designers the flexibility to prevent bus contention. The AT27LV256A operating with V at 3.0V produces TTL-level outputs that are compati- CC ble with standard TTL logic devices operating at V = 5.0V. The device is also capable of CC standard, 5V operation, making it ideally suited for dual supply range systems or card prod- ucts that are pluggable in both 3V and 5V hosts. The AT27LV256A 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 100s/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. The AT27LV256A programs in exactly the same way as a standard, 5V Atmel AT27C256R, and uses the same programming equipment. 0547HEPROM4/112. Pin configurations 32-lead PLCC Pin name Function Top view A0 - A14 Addresses O0 - O7 Outputs CE Chip Enable A6 5 29 A8 A5 6 28 A9 OE Output Enable A4 7 27 A11 NC No Connect A3 8 26 NC A2 9 25 OE A1 10 24 A10 A0 11 23 CE NC 12 22 O7 O0 13 21 O6 Note: PLCC package pins 1 and 17 are dont connect. 3. System considerations Switching between active and standby conditions via the chip enable pin may produce transient voltage excursions. Unless accommodated by the system design, these transients may exceed datasheet limits, resulting in device nonconformance. At a minimum, a 0.1F, high-frequency, low inherent inductance, ceramic capacitor should be utilized for each device. This capacitor should be connected between the V and ground terminals of the device, as close to the device as possible. CC Additionally, to stabilize the supply voltage level on printed circuit boards with large EPROM arrays, a 4.7F bulk electrolytic capacitor should be utilized, again connected between the V and ground terminals. This capacitor should be positioned as CC close as possible to the point where the power supply is connected to the array. Figure 3-1. Block diagram 2 Atmel AT27LV256A 0547HEPROM4/11 O1 14 4 A7 O2 15 3 A12 GND 16 2 VPP NC 17 1 NC O3 18 32 VCC O4 19 31 A14 O5 20 30 A13