AT28BV64 Features • • • • • • • • 2.7V to 3.6V Supply Full Read and Write Operation Low Power Dissipation 8 mA Active Current 50 µA CMOS Standby Current Read Access Time - 300 ns Byte Write - 3 ms Direct Microprocessor Control DATA Polling READY/BUSY Open Drain Output High Reliability CMOS Technology Endurance: 100,000 Cycles Data Retention: 10 Years JEDEC Approved Byte-Wide Pinout Commercial and Industrial Temperature Ranges 64K (8K x 8) Battery-Voltage CMOS E2PROM Description The AT28BV64 is a low-voltage, low-power Electrically Erasable and Programmable Read Only Memory specifically designed for battery powered applications. Its 64K of memory is organized 8,192 words by 8 bits. Manufactured with Atmel’s advanced nonvolatile CMOS technology, the device offers access times to 200 ns with power dissipation less than 30 mW. When the device is deselected the standby current is less than 50 µA. The AT28BV64 is accessed like a Static RAM for the read or write cycles without the need for external components. During a byte write, the address and data are latched internally, freeing the microprocessor address and data bus for other operations. Fol(continued) Pin Configurations PDIP, SOIC Top View Pin Name Function A0 - A12 Addresses CE Chip Enable OE Output Enable WE Write Enable I/O0 - I/O7 Data Inputs/Outputs RDY/BUSY Ready/Busy Output NC No Connect DC Don’t Connect PLCC Top View AT28BV64 TSOP Top View 0493A 2-127 Description (Continued) lowing the initiation of a write cycle, the device will go to a busy state and automatically clear and write the latched data using an internal control timer. The device includes two methods for detecting the end of a write cycle, level detection of RDY/BUSY and DATA polling of I/O7. Once the end of a write cycle has been detected, a new access for a read or write can begin. Atmel’s 28BV64 has additional features to ensure high quality and manufacturability. The device utilizes error correction internally for extended endurance and for improved data retention characteristics. An extra 32-bytes of E2PROM are available for device identification or tracking. Block Diagram Absolute Maximum Ratings* Temperature Under Bias................. -55°C to +125°C Storage Temperature...................... -65°C to +150°C All Input Voltages (including NC Pins) with Respect to Ground ................... -0.6V to +6.25V All Output Voltages with Respect to Ground .............-0.6V to VCC + 0.6V Voltage on OE and A9 with Respect to Ground ................... -0.6V to +13.5V 2-128 AT28BV64 *NOTICE: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. AT28BV64 Device Operation READ: The AT28BV64 is accessed like a Static RAM. When CE and OE are low and WE is high, the data stored at the memory location determined by the address pins is asserted on the outputs. The outputs are put in a high impedance state whenever CE or OE is high. This dual line control gives designers increased flexibility in preventing bus contention. BYTE WRITE: Writing data into the AT28BV64 is similar to writing into a Static RAM. A low pulse on the WE or CE input with OE high and CE or WE low (respectively) initiates a byte write. The address location is latched on the falling edge of WE (or CE); the new data is latched on the rising edge. Internally, the device performs a self-clear before write. Once a byte write has been started, it will automatically time itself to completion. Once a programming operation has been initiated and for the duration of tWC, a read operation will effectively be a polling operation. DATA POLLING: The AT28BV64 provides DATA POLLING to signal the completion of a write cycle. During a write cycle, an attempted read of the data being written results in the complement of that data for I/O7 (the other outputs are indeterminate). When the write cycle is finished, true data appears on all outputs. WRITE PROTECTION: Inadvertent writes to the device are protected against in the following ways. (a) VCC sense— if VCC is below 1.8V (typical) the write function is inhibited. (b) VCC power on delay— once VCC h a s reached 2.0V the device will automatically time out 10 ms (typical) before allowing a byte write. (c) Write Inhibit— holding any one of OE low, CE high or WE high inhibits byte write cycles. READY/BUSY: Pin 1 is an open drain READY/BUSY output that can be used to detect the end of a write cycle. RDY/BUSY is actively pulled low during the write cycle and is released at the completion of the write. The open drain connection allows for OR-tying of several devices to the same RDY/BUSY line. 2-129 DC and AC Operating Range AT28BV64-30 Com. Operating Temperature (Case) 0°C - 70°C Ind. -40°C - 85°C VCC Power Supply 2.7V to 3.6V Operating Modes Mode CE OE WE I/O Read VIL VIL VIH DOUT VIL VIH VIL DIN VIH (1) Write (2) Standby/Write Inhibit X X Write Inhibit X X VIH Write Inhibit X VIL X Output Disable X VIH X High Z High Z Notes: 1. X can be VIL or VIH. 2. Refer to AC Programming Waveforms. DC Characteristics Symbol Parameter Condition Min Max Units ILI Input Load Current VIN = 0V to VCC + 1.0V 5 µA ILO Output Leakage Current VI/O = 0V to VCC 5 µA ISB VCC Standby Current CMOS CE = VCC - 0.3V to VCC + 1.0V 50 µA ICC VCC Active Current AC f = 5 MHz; IOUT = 0 mA; CE = VIL 8 mA VIL Input Low Voltage 0.6 V VIH Input High Voltage VOL Output Low Voltage VOH Output High Voltage 2-130 AT28BV64 2.0 V IOL = 1 mA 0.3 V IOL = 2 mA for RDY/BUSY 0.3 V IOH = -100 µA 2.0 V AT28BV64 AC Read Characteristics AT28BV64-30 Symbol Parameter tACC Min Max Units Address to Output Delay 300 ns tCE (1) CE to Output Delay 300 ns tOE (2) OE to Output Delay 0 150 ns tDF (3, 4) CE or OE High to Output Float 0 60 ns Output Hold from OE, CE or Address, whichever occurred first 0 tOH ns AC Read Waveforms (1, 2, 3, 4) Notes: 1. CE may be delayed up to tACC - tCE after the address transition without impact on tACC. 2. OE may be delayed up to tCE - tOE after the falling edge of CE without impact on tCE or by tACC - tOE after an address change without impact on tACC. 3. tDF is specified from OE or CE whichever occurs first (CL = 5 pF). 4. This parameter is characterized and is not 100% tested. Input Test Waveforms and Measurement Level Output Test Load tR, tF < 20 ns Pin Capacitance (f = 1 MHz, T = 25°C) (1) CIN COUT Note: Typ Max Units Conditions 4 6 pF VIN = 0V 8 12 pF VOUT = 0V 1. This parameter is characterized and is not 100% tested. 2-131 AC Write Characteristics Symbol Parameter Min tAS, tOES Address, OE Set-up Time 10 ns tAH Address Hold Time 100 ns tWP Write Pulse Width (WE or CE) 150 tDS Data Set-up Time 100 ns tDH, tOEH Data, OE Hold Time 10 ns tDB Time to Device Busy 50 ns tWC Write Cycle Time 3 ms AC Write Waveforms WE Controlled CE Controlled 2-132 AT28BV64 Max 1000 Units ns AT28BV64 Data Polling Characteristics (1) Symbol Parameter tDH Data Hold Time tOEH OE Hold Time Min OE to Output Delay tWR Write Recovery Time Max Units 10 ns 10 ns (2) tOE Typ ns 0 ns Notes: 1. These parameters are characterized and not 100% tested. 2. See AC Read Characteristics. Data Polling Waveforms 2-133 Ordering Information (1) tACC ICC (mA) (ns) Active Standby 300 Note: Operating Voltage Ordering Code Package 8 0.05 2.7V to 3.6V AT28BV64-30JC AT28BV64-30PC AT28BV64-30SC AT28BV64-30TC 32J 28P6 28S 28T Commercial (0°C to 70°C) 8 0.05 2.7V to 3.6V AT28BV64-30JI AT28BV64-30PI AT28BV64-30SI AT28BV64-30TI 32J 28P6 28S 28T Industrial (-40°C to 85°C) 1. See Valid Part Number table below. Valid Part Numbers The following table lists standard Atmel products that can be ordered. Device Numbers AT28BV64 Speed 30 Package and Temperature Combinations JC, JI, PC, PI, SC, SI, TC, TI Package Type 32J 32 Lead, Plastic J-Leaded Chip Carrier (PLCC) 28P6 28 Lead, 0.600" Wide, Plastic Dual Inline Package (PDIP) 28S 28 Lead, 0.300" Wide, Plastic Gull Wing, Small Outline (SOIC) 28T 28 Lead, Plastic Thin Small Outline Package (TSOP) 2-134 Operation Range AT28BV64