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| AT28HC64B Features * * * * * * * * * * * Fast Read Access Time - 55 ns Automatic Page Write Operation Internal Address and Data Latches for 64-Bytes Fast Write Cycle Times Page Write Cycle Time: 10 ms Maximum 1 to 64-Byte Page Write Operation Low Power Dissipation 40 mA Active Current 100 A CMOS Standby Current Hardware and Software Data Protection DATA Polling and Toggle Bit for End of Write Detection High Reliability CMOS Technology Endurance: 100,000 Cycles Data Retention: 10 Years Single 5V 10% Supply CMOS and TTL Compatible Inputs and Outputs JEDEC Approved Byte-Wide Pinout Commercial and Industrial Temperature Ranges Description The AT28HC64B is a high-performance electrically erasable and programmable read only memory (EEPROM). Its 64K of memory is organized as 8,192 words by 8 bits. Manufactured with Atmel's advanced nonvolatile CMOS technology, the device offers access times to 55 ns with power dissipation of just 220 mW. When the device is deselected, the CMOS standby current is less than 100 A. The AT28HC64B is accessed like a Static RAM for the read or write cycle without the need for external components. The device contains a 64-byte page register to allow (continued) Pin Name A0 - A12 CE OE WE I/O0 - I/O7 NC DC Function Addresses Chip Enable Output Enable Write Enable Data Inputs/Outputs No Connect Don't Connect 64K (8K x 8) High Speed CMOS E2PROM with Page Write and Software Data Protection Pin Configurations TSOP Top View AT28HC64B PDIP, SOIC Top View PLCC Top View Note: PLCC package pins 1 and 17 are DON'T CONNECT. 0274D 2-267 Description (Continued) writing of up to 64-bytes simultaneously. During a write cycle, the addresses and 1 to 64-bytes of data are internally latched, freeing the address and data bus for other operations. Following the initiation of a write cycle, the device will automatically write the latched data using an internal control timer. The end of a write cycle can be detected by 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 AT28HC64B has additional features to ensure high quality and manufacturability. The device utilizes internal error correction for extended endurance and improved data retention. An optional software data protection mechanism is available to guard against inadvertent writes. The device also includes an extra 64-bytes of EEPROM for device identification or tracking. Block Diagram Absolute Maximum Ratings* Temperature Under Bias................. -55C to +125C Storage Temperature...................... -65C to +150C 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 *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. 2-268 AT28HC64B AT28HC64B Device Operation READ: The AT28HC64B 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 the highimpedance state when either CE or OE is high. This dual line control gives designers flexibility in preventing bus contention in their systems. BYTE WRITE: A low pulse on the WE or CE input with CE or WE low (respectively) and OE high initiates a write cycle. The address is latched on the falling edge of CE or WE, whichever occurs last. The data is latched by the first rising edge of CE or WE. 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. PAGE WRITE: T h e p a g e w r i t e o p e r a t i o n o f t h e AT28HC64B allows 1 to 64-bytes of data to be written into the device during a single internal programming period. A page write operation is initiated in the same manner as a byte write; after the first byte is written, it can then be followed by 1 to 63 additional bytes. Each successive byte must be loaded within 150 s (tBLC) of the previous byte. If the tBLC limit is exceeded, the AT28HC64B will cease accepting data and commence the internal programming operation. All bytes during a page write operation must reside on the same page as defined by the state of the A6 to A12 inputs. For each WE high to low transition during the page write operation, A6 to A12 must be the same. The A0 to A5 inputs specify which bytes within the page are to be written. The bytes may be loaded in any order and may be altered within the same load period. Only bytes which are specified for writing will be written; unnecessary cycling of other bytes within the page does not occur. DATA POLLING: The AT28HC64B features DATA Polling to indicate the end of a write cycle. During a byte or page write cycle, an attempted read of the last byte written will result in the complement of the written data to be presented on I/O7. Once the write cycle has been completed, true data is valid on all outputs, and the next write cycle may begin. DATA Polling may begin at any time during the write cycle. TOGGLE BIT: I n a d d i t i o n t o DATA P o l l i n g , t he AT28HC64B provides another method for determining the end of a write cycle. During the write operation, successive attempts to read data from the device will result in I/O6 toggling between one and zero. Once the write has completed, I/O6 will stop toggling, and valid data will be read. Toggle bit reading may begin at any time during the write cycle. DATA PROTECTION: If precautions are not taken, inadvertent writes may occur during transitions of the host system power supply. Atmel has incorporated both hardware and software features that will protect the memory against inadvertent writes. HARDWARE DATA PROTECTION: Hardware features protect against inadvertent writes to the AT28HC64B in the following ways: (a) VCC sense - if VCC is below 3.8V (typical), the write function is inhibited; (b) VCC power-on delay - once VCC has reached 3.8V, the device will automatically time out 5 ms (typical) before allowing a write; (c) write inhibit - holding any one of OE low, CE high or WE high inhibits write cycles; (d) noise filter - pulses of less than 15 ns (typical) on the WE or CE inputs will not initiate a write cycle. SOFTWARE DATA PROTECTION: A software-controlled data protection feature has been implemented on the AT28HC64B. When enabled, the software data protection (SDP), will prevent inadvertent writes. The SDP feature may be enabled or disabled by the user; the AT28HC64B is shipped from Atmel with SDP disabled. SDP is enabled by the user issuing a series of three write commands in which three specific bytes of data are written to three specific addresses (refer to the Software Data Protection Algorithm diagram in this data sheet). After writing the 3-byte command sequence and waiting tWC, the entire AT28HC64B will be protected against inadvertent writes. It should be noted that even after SDP is enabled, the user may still perform a byte or page write to the AT28HC64B. This is done by preceding the data to be written by the same 3-byte command sequence used to enable SDP. Once set, SDP remains active unless the disable command sequence is issued. Power transitions do not disable SDP, and SDP protects the AT28HC64B during power-up and power-down conditions. All command sequences must conform to the page write timing specifications. The data in the enable and disable command sequences is not actually written into the device; their addresses may still be written with user data in either a byte or page write operation. After setting SDP, any attempt to write to the device without the 3-byte command sequence will start the internal write timers. No data will be written to the device, however. For the duration of tWC, read operations will effectively be polling operations. (continued) 2-269 Device Operation (Continued) DEVICE IDENTIFICATION: A n e x t r a 6 4 - b y t e s o f EEPROM memory are available to the user for device identification. By raising A9 to 12V 0.5V and using address locations 1FC0H to 1FFFH, the additional bytes may be written to or read from in the same manner as the regular memory array. DC and AC Operating Range AT28HC64B-55 Operating Temperature (Case) VCC Power Supply Com. Ind. 5V 10% 0C - 70C AT28HC64B-70 0C - 70C -40C - 85C 5V 10% AT28HC64B-90 0C - 70C -40C - 85C 5V 10% AT28HC64B-120 0C - 70C -40C - 85C 5V 10% Operating Modes Mode Read Write (2) Standby/Write Inhibit Write Inhibit Write Inhibit Output Disable Chip Erase CE VIL VIL VIH X X X VIL OE VIL VIH X (1) WE VIH VIL X VIH X X VIL I/O DOUT DIN High Z X VIL VIH VH (3) High Z High Z Notes: 1. X can be VIL or VIH. 2. Refer to the AC Write Waveforms diagrams in this data sheet. 3. VH = 12.0V 0.5V. DC Characteristics Symbol ILI ILO ISB1 ISB2 ICC VIL VIH VOL VOH Note: Parameter Input Load Current Output Leakage Current VCC Standby Current CMOS VCC Standby Current TTL VCC Active Current Input Low Voltage Input High Voltage Output Low Voltage Output High Voltage Condition VIN = 0V to VCC + 1V VI/O = 0V to VCC CE = VCC - 0.3V to VCC + 1V CE = 2.0V to VCC + 1V f = 5 MHz; IOUT = 0 mA Com., Ind. Min Max 10 10 100 2 (1) (1) Units A A A mA mA V V V V 40 0.8 2.0 IOL = 2.1 mA IOH = -400 A 2.4 .40 1. ISB1 and ISB2 for the 55 ns part is 40 mA maximum. 2-270 AT28HC64B AT28HC64B AC Read Characteristics AT28HC64B-55 AT28HC64B-70 AT28HC64B-90 AT28HC64B-120 Symbol Parameter tACC tCE (1) tOE tDF tOH (2) (3, 4) Min Max Min Max Min Max Min Max Units ns ns ns ns ns Address to Output Delay CE to Output Delay OE to Output Delay OE to Output Float Output Hold 0 0 0 55 55 30 30 0 0 0 70 70 35 35 0 0 0 90 90 40 40 0 0 0 120 120 50 50 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 < 5ns Pin Capacitance (f = 1 MHz, T = 25C) (1) Typ CIN COUT Note: Max 6 12 Units pF pF Conditions VIN = 0V VOUT = 0V 4 8 1. This parameter is characterized and is not 100% tested. 2-271 AC Write Characteristics Symbol tAS, tOES tAH tCS tCH tWP tDS tDH, tOEH Parameter Address, OE Set-up Time Address Hold Time Chip Select Set-up Time Chip Select Hold Time Write Pulse Width (WE or CE) Data Set-up Time Data, OE Hold Time Min 0 50 0 0 100 50 0 Max Units ns ns ns ns ns ns ns AC Write Waveforms WE Controlled CE Controlled 2-272 AT28HC64B AT28HC64B Page Mode Characteristics Symbol tWC tAS tAH tDS tDH tWP tBLC tWPH Parameter Write Cycle Time Address Set-up Time Address Hold Time Data Set-up Time Data Hold Time Write Pulse Width Byte Load Cycle Time Write Pulse Width High 50 0 50 50 0 100 150 Min Max 10 Units ms ns ns ns ns ns s ns Page Mode Write Waveforms (1, 2) Notes: 1. A6 through A12 must specify the same page address during each high to low transition of WE (or CE). 2. OE must be high only when WE and CE are both low. Chip Erase Waveforms tS = tH = 5 sec (min.) tW = 10 msec (min.) VH = 12.0V 0.5V 2-273 Software Data Protection Enable Algorithm (1) LOAD DATA AA TO ADDRESS 1555 LOAD DATA 55 TO ADDRESS 0AAA LOAD DATA A0 TO ADDRESS 1555 LOAD DATA XX TO ANY ADDRESS (4) LOAD LAST BYTE TO LAST ADDRESS Software Data Protection Disable Algorithm (1) LOAD DATA AA TO ADDRESS 1555 LOAD DATA 55 TO ADDRESS 0AAA LOAD DATA 80 TO ADDRESS 1555 LOAD DATA AA TO ADDRESS 1555 LOAD DATA 55 TO ADDRESS 0AAA LOAD DATA 20 TO ADDRESS 1555 LOAD DATA XX TO ANY ADDRESS (4) LOAD LAST BYTE TO LAST ADDRESS WRITES ENABLED (2) ENTER DATA PROTECT STATE Notes for software program code: 1. Data Format: I/O7 - I/O0 (Hex); Address Format: A12 - A0 (Hex). 2. Write Protect state will be activated at end of write even if no other data is loaded. 3. Write Protect state will be deactivated at end of write period even if no other data is loaded. 4. 1 to 64-bytes of data are loaded. EXIT DATA PROTECT STATE (3) Software Protected Write Cycle Waveforms (1, 2) Notes: 1. A6 through A12 must specify the same page address during each high to low transition of WE (or CE) after the software code has been entered. 2. OE must be high only when WE and CE are both low. 2-274 AT28HC64B AT28HC64B Data Polling Characteristics (1) Symbol tDH tOEH tOE tWR Parameter Data Hold Time OE Hold Time OE to Output Delay (2) Min 0 0 0 Typ Max Units ns ns ns ns Write Recovery Time Notes: 1. These parameters are characterized and not 100% tested. 2. See AC Read Characteristics. Data Polling Waveforms Toggle Bit Characteristics (1) Symbol tDH tOEH tOE tOEHP tWR Parameter Data Hold Time OE Hold Time OE to Output Delay OE High Pulse Write Recovery Time (2) Min 10 10 150 0 Typ Max Units ns ns ns ns ns Notes: 1. These parameters are characterized and not 100% tested. 2. See AC Read Characteristics. Toggle Bit Waveforms (1, 2, 3) Notes: 1. Toggling either OE or CE or both OE and CE will operate toggle bit. 2. Beginning and ending state of I/O6 will vary. 3. Any address location may be used, but the address should not vary. 2-275 2-276 AT28HC64B AT28HC64B Ordering Information (1) tACC (ns) 55 ICC (mA) Active 40 Standby 0.1 AT28HC64B-55JC AT28HC64B-55PC AT28HC64B-55SC AT28HC64B-70JC AT28HC64B-70PC AT28HC64B-70SC AT28HC64B-70TC AT28HC64B-70JI AT28HC64B-70PI AT28HC64B-70SI AT28HC64B-70TI AT28HC64B-90JC AT28HC64B-90PC AT28HC64B-90SC AT28HC64B-90TC AT28HC64B-90JI AT28HC64B-90PI AT28HC64B-90SI AT28HC64B-90TI AT28HC64B-12JC AT28HC64B-12PC AT28HC64B-12SC AT28HC64B-12TC AT28HC64B-12JI AT28HC64B-12PI AT28HC64B-12SI AT28HC64B-12TI Ordering Code Package 32J 28P6 28S 32J 28P6 28S 28T 32J 28P6 28S 28T 32J 28P6 28S 28T 32J 28P6 28S 28T 32J 28P6 28S 28T 32J 28P6 28S 28T Operation Range Commercial (0C to 70C) Commercial (0C to 70C) 70 40 0.1 40 0.1 Industrial (-40C to 85C) 90 40 0.1 Commercial (0C to 70C) 40 0.1 Industrial (-40C to 85C) 120 40 0.1 Commercial (0C to 70C) 40 0.1 Industrial (-40C to 85C) Note: 1. See Valid Part Number table below. 2-277 Valid Part Numbers The following table lists standard Atmel products that can be ordered. Device Numbers AT28HC64B AT28HC64B AT28HC64B AT28HC64B Speed 55 70 90 12 Package and Temperature Combinations PC, SC JI, PC, PI, SC, SI, TC, TI JI, PC, PI, SC, SI, TC, TI JI, PC, PI, SC, SI, TC, TI Package Type 32J 28P6 28S 28T 32 Lead, Plastic J-Leaded Chip Carrier (PLCC) 28 Lead, 0.600" Wide, Plastic Dual Inline Package (PDIP) 28 Lead, 0.300" Wide, Plastic Gull Wing Small Outline (SOIC) 28 Lead, Plastic Thin Small Outline Package (TSOP) 2-278 AT28HC64B |
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