CAT28C257 256 kb CMOS Parallel EEPROM Description The CAT28C257 is a fast, low power, 5 V−only CMOS Parallel EEPROM organized as 32K x 8−bits. It requires a simple interface for in−system programming. On−chip address and data latches, self−timed write cycle with auto−clear and VCC power up/down write protection eliminate additional timing and protection hardware. DATA Polling and Toggle status bits signal the start and end of the self−timed write cycle. Additionally, the CAT28C257 features hardware and software write protection. The CAT28C257 is manufactured using ON Semiconductor’s advanced CMOS floating gate technology. It is designed to endure 100,000 program/erase cycles and has a data retention of 100 years. The device is available in JEDEC approved 28−pin DIP or 32−pin PLCC packages. • • • • • • • A0−A14 – Active: 25 mA Max. – Standby: 150 mA Max. Simple Write Operation: – On−chip Address and Data Latches – Self−timed Write Cycle with Auto−clear Fast Write Cycle Time: − 5 ms Max. CMOS and TTL Compatible I/O Automatic Page Write Operation: − 1 to 128 Bytes in 5 ms − Page Load Timer End of Write Detection: − Toggle Bit − DATA Polling Hardware and Software Write Protection 100,000 Program/Erase Cycles 100 Year Data Retention Commercial, Industrial and Automotive Temperature Ranges © Semiconductor Components Industries, LLC, 2009 December, 2009 − Rev. 6 PLCC−32 N, G SUFFIX CASE 776AK Pin Name • Fast Read Access Times: 120/150 ns • Low Power CMOS Dissipation: • PDIP−28 P, L SUFFIX CASE 646AE PIN FUNCTION Features • http://onsemi.com 1 I/O0−I/O7 Function Address Inputs Data Inputs/Outputs CE Chip Enable OE Output Enable WE Write Enable VCC 5 V Supply VSS Ground NC No Connect ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 13 of this data sheet. Publication Order Number: CAT28C257/D CAT28C257 PIN CONFIGURATION 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 VCC WE A13 A8 A9 A11 OE A10 CE I/O7 I/O6 I/O5 I/O4 I/O3 A6 A5 A4 A3 A2 A1 A0 NC I/O0 4 3 2 1 32 31 30 5 29 6 28 7 27 8 26 9 25 10 24 11 23 12 22 13 21 14 1516 171819 20 A8 A9 A11 NC OE A10 CE I/O7 I/O6 I/O1 I/O2 VSS NC I/O3 I/O4 I/O5 A14 A12 A7 A6 A5 A4 A3 A2 A1 A0 I/O0 I/O1 I/O2 VSS PLCC Package (N, G) A7 A12 A14 NC VCC WE A13 DIP Package (P, L) (Top Views) A7−A14 VCC CE OE WE INADVERTENT WRITE PROTECTION ADDR. BUFFER & LATCHES 32,768 x 8 EEPROM ARRAY HIGH VOLTAGE GENERATOR 128 BYTE PAGE REGISTER CONTROL LOGIC TIMER A0−A6 ROW DECODER ADDR. BUFFER & LATCHES I/O BUFFERS DATA POLLING AND TOGGLE BIT COLUMN DECODER Figure 1. Block Diagram http://onsemi.com 2 I/O0−I/O7 CAT28C257 Table 1. ABSOLUTE MAXIMUM RATINGS Parameters Ratings Units Temperature Under Bias –55 to +125 °C Storage Temperature –65 to +150 °C –2.0 V to +VCC + 2.0 V V Voltage on Any Pin with Respect to Ground (Note 1) VCC with Respect to Ground −2.0 to +7.0 V Package Power Dissipation Capability (TA = 25°C) 1.0 W Lead Soldering Temperature (10 secs) 300 °C Output Short Circuit Current (Note 2) 100 mA Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. 1. The minimum DC input voltage is −0.5 V. During transitions, inputs may undershoot to −2.0 V for periods of less than 20 ns. Maximum DC voltage on output pins is VCC + 0.5 V, which may overshoot to VCC + 2.0 V for periods of less than 20 ns. 2. Output shorted for no more than one second. No more than one output shorted at a time. Table 2. RELIABILITY CHARACTERISTICS (Note 3) Symbol Parameter Test Method Min Typ Max Units Endurance MIL−STD−883, Test Method 1033 104 or 105 Cycles/Byte TDR Data Retention MIL−STD−883, Test Method 1008 100 Years VZAP ESD Susceptibility MIL−STD−883, Test Method 3015 2,000 V Latch−Up JEDEC Standard 17 100 mA NEND ILTH (Note 4) 3. These parameters are tested initially and after a design or process change that affects the parameters. 4. Latch−up protection is provided for stresses up to 100 mA on address and data pins from −1 V to VCC + 1 V. Table 3. D.C. OPERATING CHARACTERISTICS (VCC = 5 V ±10%, unless otherwise specified.) Limits Symbol ICC Parameter Test Conditions Min Typ Max Units VCC Current (Operating, TTL) CE = OE = VIL, f = 6 MHz, All I/O’s Open 30 mA VCC Current (Operating, CMOS) CE = OE = VILC, f = 6 MHz, All I/O’s Open 25 mA VCC Current (Standby, TTL) CE = VIH, All I/O’s Open 1 mA VCC Current (Standby, CMOS) CE = VIHC, All I/O’s Open 150 mA ILI Input Leakage Current VIN = GND to VCC −10 10 mA ILO Output Leakage Current VOUT = GND to VCC, CE = VIH −10 10 mA VIH (Note 6) High Level Input Voltage 2 VCC + 0.3 V VIL (Note 5) Low Level Input Voltage −0.3 0.8 V ICCC (Note 5) ISB ISBC (Note 6) VOH High Level Output Voltage IOH = −400 mA VOL Low Level Output Voltage IOL = 2.1 mA VWI Write Inhibit Voltage 2.4 3.5 5. VILC = −0.3 V to +0.3 V 6. VIHC = VCC −0.3 V to VCC + 0.3 V http://onsemi.com 3 V 0.4 V V CAT28C257 Table 4. MODE SELECTION Mode CE WE OE I/O Power Read L H L DOUT ACTIVE Byte Write (WE Controlled) L H DIN ACTIVE L H DIN ACTIVE Byte Write (CE Controlled) Standby and Write Inhibit H X X High−Z STANDBY Read and Write Inhibit X H H High−Z ACTIVE Table 5. CAPACITANCE (TA = 25°C, f = 1.0 MHz, VCC = 5 V) Symbol Test Min Typ Max Conditions Units CI/O (Note 7) Input/Output Capacitance 10 VI/O = 0 V pF CIN (Note 7) Input Capacitance 6 VIN = 0 V pF 7. This parameter is tested initially and after a design or process change that affects the parameter. Table 6. A.C. CHARACTERISTICS, READ CYCLE (VCC = 5 V ±10%, unless otherwise specified.) 28C257−12 Min Parameter Symbol Typ 28C257−15 Max 120 Min Typ Max Units tRC Read Cycle Time 150 ns tCE CE Access Time 120 150 ns tAA Address Access Time 120 150 ns tOE OE Access Time 50 70 ns tLZ (Note 8) CE Low to Active Output 0 0 ns tOLZ (Note 8) OE Low to Active Output 0 0 ns tHZ (Notes 8, 9) CE High to High−Z Output 50 50 ns tOHZ (Notes 8, 9) OE High to High−Z Output 50 50 ns tOH (Note 8) Output Hold from Address Change 0 0 ns 8. This parameter is tested initially and after a design or process change that affects the parameter. 9. Output floating (High−Z) is defined as the state when the external data line is no longer driven by the output buffer. Table 7. POWER−UP TIMING Symbol Parameter tPUR Power−Up to Read tPUW Power−Up to Write Min 5 http://onsemi.com 4 Typ Max Units 100 ms 10 ms CAT28C257 Table 8. A.C. CHARACTERISTICS, WRITE CYCLE (VCC = 5 V ±10%, unless otherwise specified.) 28C257−12 Symbol Min Parameter Typ 28C257−15 Max Min Typ 5 Max Units 5 ms tWC Write Cycle Time tAS Address Setup Time 0 0 ns tAH Address Hold Time 50 50 ns tCS CE Setup Time 0 0 ns tCH CE Hold Time 0 0 ns tCW (Note 10) CE Pulse Time 100 100 ns tOES OE Setup Time 0 0 ns tOEH OE Hold Time 0 0 ns tWP (Note 10) WE Pulse Width 100 100 ns tDS Data Setup Time 50 50 ns tDH Data Hold Time 0 0 Write Inhibit Period After Power−up 5 10 5 10 ms 0.1 100 0.1 100 ms tINIT (Note 11) tBLC (Notes 11, 12) Byte Load Cycle Time ns 10. A write pulse of less than 20 ns duration will not initiate a write cycle. 11. This parameter is tested initially and after a design or process change that affects the parameter. 12. A timer of duration tBLC max. begins with every LOW to HIGH transition of WE. If allowed to time out, a page or byte write will begin; however a transition from HIGH to LOW within tBLC max. stops the timer. VCC − 0.3 V 2.0 V INPUT PULSE LEVELS REFERENCE POINTS 0.8 V 0.0 V Figure 2. A.C. Testing Input/Output Waveform (Note 13) 13. Input rise and fall times (10% and 90%) < 10 ns. 1.3 V 1N914 3.3 K DEVICE UNDER TEST OUT CL = 100 pF CL INCLUDES JIG CAPACITANCE Figure 3. A.C. Testing Load Circuit (example) http://onsemi.com 5 CAT28C257 DEVICE OPERATION Byte Write A write cycle is executed when both CE and WE are low, and OE is high. Write cycles can be initiated using either WE or CE, with the address input being latched on the falling edge of WE or CE, whichever occurs last. Data, conversely, is latched on the rising edge of WE or CE, whichever occurs first. Once initiated, a byte write cycle automatically erases the addressed byte and the new data is written within 5 ms. Read Data stored in the CAT28C257 is transferred to the data bus when WE is held high, and both OE and CE are held low. The data bus is set to a high impedance state when either CE or OE goes high. This 2−line control architecture can be used to eliminate bus contention in a system environment. tRC ADDRESS tCE CE tOE OE WE tOLZ VIH tLZ tHZ tOH HIGH−Z DATA OUT tOHZ tAA DATA VALID DATA VALID Figure 4. Read Cycle tWC ADDRESS tAS tAH tCH tCS CE OE tOES tOEH tWP WE tBLC DATA OUT DATA IN HIGH−Z DATA VALID tDS tDH Figure 5. Byte Write Cycle [WE Controlled] http://onsemi.com 6 CAT28C257 Page Write can be loaded in any order) during the first and subsequent write cycles. Each successive byte load cycle must begin within tBLC MAX of the falling edge of the preceding WE pulse. There is no page write window limitation as long as WE is pulsed low within tBLC MAX. Upon completion of the page write sequence, WE must stay high a minimum of tBLC MAX for the internal automatic program cycle to commence. This programming cycle consists of an erase cycle, which erases any data that existed in each addressed cell, and a write cycle, which writes new data back into the cell. A page write will only write data to the locations that were addressed and will not rewrite the entire page. The page write mode of the CAT28C257 (essentially an extended BYTE WRITE mode) allows from 1 to 128 bytes of data to be programmed within a single EEPROM write cycle. This effectively reduces the byte−write time by a factor of 128. Following an initial WRITE operation (WE pulsed low, for tWP, and then high) the page write mode can begin by issuing sequential WE pulses, which load the address and data bytes into a 128 byte temporary buffer. The page address where data is to be written, specified by bits A7 to A14, is latched on the last falling edge of WE. Each byte within the page is defined by address bits A0 to A6 (which tWC ADDRESS tAS tAH tBLC tCW CE tOEH OE tCS tOES tCH WE HIGH−Z DATA OUT DATA IN DATA VALID tDH tDS Figure 6. Byte Write Cycle [CE Controlled] OE CE tWP tBLC WE ADDRESS tWC LAST BYTE I/O BYTE 0 BYTE 1 BYTE 2 BYTE n Figure 7. Page Mode Write Cycle http://onsemi.com 7 BYTE n+1 BYTE n+2 CAT28C257 DATA Polling Toggle Bit DATA polling is provided to indicate the completion of write cycle. Once a byte write or page write cycle is initiated, attempting to read the last byte written will output the complement of that data on I/O7 (I/O0–I/O6 are indeterminate) until the programming cycle is complete. Upon completion of the self−timed write cycle, all I/O’s will output true data during a read cycle. In addition to the DATA Polling feature of the CAT28C257, the device offers an additional method for determining the completion of a write cycle. While a write cycle is in progress, reading data from the device will result in I/O6 toggling between one and zero. However, once the write is complete, I/O6 stops toggling and valid data can be read from the device. ADDRESS CE WE tOEH tOES tOE OE Figure 8. DATA Polling WE CE tOEH tOES tOE OE I/O6 (Note 14) (Note 14) Figure 9. Toggle Bit 14. Beginning and ending state of I/O6 is indeterminate. http://onsemi.com 8 CAT28C257 Hardware Data Protection 4. Noise pulses of less than 20 ns on the WE or CE inputs will not result in a write cycle. The following is a list of hardware data protection features that are incorporated into the CAT28C257. 1. VCC sense provides for write protection when VCC falls below 3.5 V min. 2. A power on delay mechanism, tINIT (see AC characteristics), provides a 5 to 10 ms delay before a write sequence, after VCC has reached 3.5 V min. 3. Write inhibit is activated by holding any one of OE low, CE high or WE high. WRITE DATA: ADDRESS: WRITE DATA: ADDRESS: WRITE DATA: ADDRESS: Software Data Protection The CAT28C257 features a software controlled data protection scheme which, once enabled, requires a data algorithm to be issued to the device before a write can be performed. The device is shipped from ON Semiconductor with the software protection NOT ENABLED (the CAT28C257 is in the standard operating mode). WRITE DATA: AA ADDRESS: 5555 WRITE DATA: 55 ADDRESS: 2AAA WRITE DATA: A0 ADDRESS: 5555 WRITE DATA: SOFTWARE DATA PROTECTION ACTIVATED (Note 15) WRITE DATA: ADDRESS: WRITE DATA: XX TO ANY ADDRESS ADDRESS: WRITE LAST BYTE TO LAST ADDRESS WRITE DATA: ADDRESS: Figure 10. Write Sequence for Activating Software Data Protection AA 5555 55 2AAA 80 5555 AA 5555 55 2AAA 20 5555 Figure 11. Write Sequence for Deactivating Software Data Protection 15. Write protection is activated at this point whether or not any more writes are completed. Writing to addresses must occur within tBLC Max., after SDP activation. http://onsemi.com 9 CAT28C257 To activate the software data protection, the device must be sent three write commands to specific addresses with specific data (Figure 10). This sequence of commands (along with subsequent writes) must adhere to the page write timing specifications (Figure 12). Once this is done, all subsequent byte or page writes to the device must be preceded by this same set of write commands. The data protection mechanism is activated until a deactivate sequence is issued regardless of power on/off transitions. This gives the user added inadvertent write protection on power−up in addition to the hardware protection provided. DATA ADDRESS AA 5555 To allow the user the ability to program the device with an EEPROM programmer (or for testing purposes) there is a software command sequence for deactivating the data protection. The six step algorithm (Figure 11) will reset the internal protection circuitry, and the device will return to standard operating mode (Figure 13 provides reset timing). After the sixth byte of this reset sequence has been issued, standard byte or page writing can commence. 55 2AAA tWC A0 5555 BYTE OR PAGE CE tWP tBLC WRITES ENABLED WE Figure 12. Software Data Protection Timing DATA ADDRESS AA 5555 55 2AAA 80 5555 AA 5555 55 2AAA 20 5555 tWC SDP RESET CE DEVICE UNPROTECTED WE Figure 13. Resetting Software Data Protection Timing http://onsemi.com 10 CAT28C257 PACKAGE DIMENSIONS PLCC 32 CASE 776AK−01 ISSUE O PIN#1 IDENTIFICATION E1 E E2 D1 A2 D A3 TOP VIEW END VIEW b1 b e D2 SIDE VIEW Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MS-016. SYMBOL MIN A2 0.38 A3 2.54 2.80 11 MAX b 0.33 0.54 b1 0.66 0.82 D 12.32 12.57 D1 11.36 11.50 D2 9.56 11.32 E 14.86 15.11 E1 13.90 14.04 E2 12.10 13.86 e http://onsemi.com NOM 1.27 BSC CAT28C257 PACKAGE DIMENSIONS PDIP−28, 600 mils CASE 646AE−01 ISSUE A SYMBOL MIN NOM A E1 E D 6.35 A1 0.39 A2 3.18 4.95 b 0.36 0.55 b1 0.77 1.77 c 0.21 0.38 D 35.10 39.70 E 15.24 15.87 E1 12.32 e TOP VIEW A2 A1 b1 e 14.73 2.54 BSC eB 15.24 17.78 L 2.93 5.08 A L b c eB SIDE VIEW END VIEW Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MS-011. http://onsemi.com 12 MAX CAT28C257 Example of Ordering Information (Note 16) Prefix Device # Suffix CAT 28C257 N Company ID (Optional) Product Number 28C257 P: N: L: G: I − 12 Tape & Reel (Note 19) T: Tape & Reel Temperature Range Blank = Commercial (0°C to +70°C) I = Industrial (−40°C to +85°C) A = Automotive (−40°C to +105°C) (Note 18) Package PDIP (Note 17) PLCC (Note 17) PDIP (Lead Free, Halogen Free) PLCC (Lead Free, Halogen Free) T Speed 12: 120 ns 15: 150 ns 16. The device used in the above example is a CAT28C257NI−12T (100,000 Cycle Endurance, PLCC, Industrial Temperature, 120 ns Access Time, Tape & Reel). 17. Solder−plate (tin−lead) packages, contact Factory for availability. 18. −40°C to +125°C is available upon request. 19. For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specifications Brochure, BRD8011/D. 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