X28C256D-20 XICOR [Xicor Inc.], X28C256D-20 Datasheet
X28C256D-20
Available stocks
Related parts for X28C256D-20
X28C256D-20 Summary of contents
Page 1
... RAMs. The X28C256 supports a 64-byte page write operation, effectively providing a 78 s/byte write cycle and en- abling the entire memory to be typically written in less than 2.5 seconds. The X28C256 also features DATA and Toggle Bit Polling, a system software support scheme used to indicate the early completion of a write cycle ...
Page 2
... X28C256 PIN DESCRIPTIONS Addresses (A – The Address inputs select an 8-bit memory location during a read or write operation. Chip Enable (CE) The Chip Enable input must be LOW to enable all read/ write operations. When CE is HIGH, power consumption is reduced. Output Enable (OE) The Output Enable input controls the data output buffers and is used to initiate read operations ...
Page 3
... Page Write Operation The page write feature of the X28C256 allows the entire memory to be written in 2.5 seconds. Page write allows two to sixty-four bytes of data to be consecutively written to the X28C256 prior to the commencement of the internal programming cycle. The host can fetch data ...
Page 4
X28C256 DATA POLLING I/O 7 Figure 2. DATA Polling Bus Sequence LAST WRITE I – Figure 3. DATA Polling Software Flow WRITE DATA WRITES COMPLETE? YES SAVE LAST DATA ...
Page 5
X28C256 THE TOGGLE BIT I/O 6 Figure 4. Toggle Bit Bus Sequence LAST WRITE I Beginning and ending state of I/O 6 will vary. Figure 5. Toggle Bit Software Flow LAST WRITE LOAD ACCUM ...
Page 6
X28C256 HARDWARE DATA PROTECTION The X28C256 provides three hardware features (com- patible with X28C64) that protect nonvolatile data from inadvertent writes. • Noise Protection—A WE pulse typically less than 20ns will not initiate a write cycle. • Default V Sense—All ...
Page 7
X28C256 SOFTWARE DATA PROTECTION Figure 6. Timing Sequence—Byte or Page Write DATA AA ADDR. 5555 CE WE Figure 7. Write Sequence for Software Data Protection WRITE DATA AA TO ADDRESS 5555 WRITE DATA 55 TO ADDRESS 2AAA ...
Page 8
X28C256 RESETTING SOFTWARE DATA PROTECTION Figure 8. Reset Software Data Protection Timing Sequence V CC DATA AA 55 ADDR. 5555 2AAA CE WE Figure 9. Software Sequence to Deactivate Software Data Protection WRITE DATA AA TO ADDRESS 5555 WRITE DATA ...
Page 9
... Because the X28C256 has two power modes, standby and active, proper decoupling of the memory array is of Normalized Active Supply Current vs. Ambient Temperature 1 ...
Page 10
X28C256 ABSOLUTE MAXIMUM RATINGS* Temperature under Bias X28C256 ...................................... – +85 C X28C256I, X28C256M ............... – +135 C Storage Temperature ....................... – +150 C Voltage on any Pin with Respect ....................................... ...
Page 11
X28C256 ENDURANCE AND DATA RETENTION Parameter Endurance Data Retention POWER-UP TIMING Symbol (4) t Power-up to Read Operation PUR PUW (4) t Power-up to Write Operation CAPACITANCE 1MHz Symbol I/O (4) C ...
Page 12
X28C256 A.C. CHARACTERISTICS (over recommended operating conditions, unless otherwise specified) Read Cycle Limits Symbol Parameter t Read Cycle Time RC t Chip Enable Access Time CE t Address Access Time AA t Output Enable Access Time OE CE LOW to ...
Page 13
X28C256 WRITE CYCLE LIMITS Symbol Parameter (7) t Write Cycle Time WC t Address Setup Time AS t Address Hold Time AH t Write Setup Time CS t Write Hold Time CH CE Pulse Width HIGH Setup ...
Page 14
... Notes: (10) Between successive byte writes within a page write operation, OE can be strobed LOW: e.g. this can be done with CE and WE HIGH to fetch data from another memory device within the system for the next write; or with WE HIGH and CE LOW effectively performing a polling operation. ...
Page 15
X28C256 DATA Polling Timing Diagram (12) An ADDRESS I/O 7 (12) Toggle Bit Timing Diagram OEH OE HIGH Z I Starting and ending state of I/O 6 will ...
Page 16
X28C256 PACKAGING INFORMATION 28-LEAD PLASTIC DUAL IN-LINE PACKAGE TYPE P PIN 1 INDEX PIN 1 SEATING PLANE 0.160 (4.06) 0.120 (3.05) 0.110 (2.79) 0.090 (2.29) TYP. 0.010 (0.25) NOTE: 1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) 2. PACKAGE ...
Page 17
X28C256 PACKAGING INFORMATION 28-LEAD HERMETIC DUAL IN-LINE PACKAGE TYPE D PIN 1 SEATING PLANE 0.200 (5.08) 0.150 (3.81) MIN. 0.125 (3.18) 0.110 (2.79) 0.090 (2.29) TYP. 0.100 (2.54) NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) 1.490 (37.85) MAX. ...
Page 18
X28C256 PACKAGING INFORMATION 32-LEAD PLASTIC LEADED CHIP CARRIER PACKAGE TYPE J 0.420 (10.67) 0.045 (1.14 0.495 (12.57) 0.485 (12.32) TYP. 0.490 (12.45) 0.453 (11.51) 0.447 (11.35) TYP. 0.450 (11.43) 0.300 (7.62) REF. PIN 1 NOTES: 1. ALL DIMENSIONS ...
Page 19
X28C256 PACKAGING INFORMATION 32-PAD CERAMIC LEADLESS CHIP CARRIER PACKAGE TYPE E 0.300 (7.62) 0.015 (0.38) 0.003 (0.08) PIN 1 0.200 (5.08) BSC 0.028 (0.71) 0.022 (0.56) (32) PLCS. 0.458 (11.63) 0.442 (11.22) 0.458 (11.63) NOTE: 1. ALL DIMENSIONS IN INCHES ...
Page 20
X28C256 PACKAGING INFORMATION 0.740 (18.80) MAX. 0.006 (0.15) 0.003 (0.08) 0.370 (9.40) 0.250 (6.35) TYP. 0.300 2 PLCS. NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) 28-LEAD CERAMIC FLAT PACK TYPE F PIN 1 INDEX 1 0.440 (11.18) MAX. ...
Page 21
X28C256 PACKAGING INFORMATION 28-LEAD CERAMIC PIN GRID ARRAY PACKAGE TYPE K TYP. 0.100 (2.54) ALL LEADS 0.660 (16.76) 0.640 (16.26) NOTE: ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS ...
Page 22
X28C256 PACKAGING INFORMATION 28-LEAD PLASTIC SMALL OUTLINE GULL WING PACKAGE TYPE S 0.105 (2.67) 0.092 (2.34) 0.0200 (0.5080) 0.0100 (0.2540) 0 – 8 0.0350 (0.8890) 0.0160 (0.4064) NOTES: 1. ALL DIMENSIONS IN INCHES (IN PARENTHESES IN MILLIMETERS) 2. FORMED LEAD ...
Page 23
X28C256 PACKAGING INFORMATION SEE NOTE 2 8.02 (0.315) 7.98 (0.314) 1.18 (0.046) 1.02 (0.040) 0.58 (0.023) 0.42 (0.017) SOLDER PADS FOOTPRINT NOTE: 1. ALL DIMENSIONS ARE SHOWN IN MILLIMETERS (INCHES IN PARENTHESES). 32-LEAD THIN SMALL OUTLINE PACKAGE (TSOP) TYPE T ...
Page 24
X28C256 ORDERING INFORMATION Device LIMITED WARRANTY Devices sold by Xicor, Inc. are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Xicor, Inc. makes no warranty, express, statutory, implied description regarding the ...