NM27C256 144-Bit (32K High Performance CMOS EPROM NM27C256 256K E

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NM27C256 144-Bit (32K High Performance CMOS EPROM NM27C256 256K E

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NM27C256 144-Bit (32K High Performance CMOS EPROM
NM27C256 144-Bit (32K High Performance CMOS EPROM
NM27C256 256K Electrically Programmable Read Only Memory manufactured National's latest CMOS split gate EPROM technology which enables operate speeds fast access time over full operating range NM27C256 provides microprocessor-based systems extensive storage capacity large portions operating system application software access time provides high speed operation with high-performance CPUs NM27C256 offers single chip solution code storage requirements 100% firmware-based equipment Frequently-used software routines quickly executed from EPROM storage greatly enhancing system utility NM27C256 configured standard EPROM pinout which provides easy upgrade path systems which currently using standard EPROMs NM27C256 member high density EPROM Family which range densities
Features
High performance CMOS access time JEDEC standard configuration 28-pin package 32-pin chip carrier Drop-in replacement 27C256 27256 Manufacturer's identification code
Block Diagram
10833
TRI-STATE registered trademark National Semiconductor Corporation HPCis trademark National Semiconductor Corporation C1995 National Semiconductor Corporation
10833
RRD-B30M65 Printed
Connection Diagrams
27C080 27C040 27C020 27C010 27C512
10833
27C512 27C010 27C020 27C040 27C080
NM27C256
Note Compatible EPROM configurations shown blocks adjacent NM27C256 pins
Commercial Temp Range Parameter Order Number NM27C256 NM27C256 NM27C256 Access Time (ns)
Extended Temp Range (b40 Parameter Order Number NM27C256 NM27C256 NM27C256 Access Time (ns)
Military Temp Range (b55 Parameter Order Number NM27C256 NM27C256 Access Time (ns)
Note Surface mount PLCC package available commercial extended temperature ranges only
Package Types NM27C256 Quartz-Windowed Ceramic Plastic Surface-Mount PLCC packages conform JEDEC standard
versions guaranteed function slower
speeds PLCC Names Symbol Description Addresses Chip Enable Output Enable Outputs Program Don't Care (during Read)
10833
Absolute Maximum Ratings (Note
Military Aerospace specified devices required please contact National Semiconductor Sales Office Distributors availability specifications Storage Temperature Input Voltages except with Respect Ground with Respect Ground Supply Voltage with Respect Ground
Protection Output Voltages with Respect Ground
2000V
Operating Range
Range Comm'l Industrial Military
Temperature
Read Operation Electrical Characteristics Over Operating Range with
Symbol ISB1 (Note ISB2 ICC1 Parameter Input Level Input High Level Output Voltage Output High Voltage Standby Current (CMOS) Standby Current (TTL) Active Current Inputs Supply Current Read Voltage Input Load Current Output Leakage Current VOUT Inputs
Test Conditions
Units
Electrical Characteristics Over Operating Range with
Symbol tACC (Note (Note Parameter Address Output Delay Output Delay Output Delay Output Disable Output Float Output Hold from Addresses Whichever Occurred First Units
Capacitance
Symbol COUT Parameter Input Capacitance Output Capacitance
(Note Conditions VOUT Units
Test Conditions
Output Load Input Rise Fall Times Gate (Note Input Pulse Levels Timing Measurement Reference Level Inputs Outputs (Note
Waveforms (Notes
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Note Stresses above those listed under ``Absolute Maximum Ratings'' cause permanent damage device This stress rating only functional operation device these other conditions above those indicated operational sections this specification implied Exposure absolute maximum rating conditions extended periods affect device reliability Note This parameter only sampled 100% tested Note delayed tACC after falling edge without impacting tACC Note compare level determined follows High TRI-STATE measured VOH1 (DC) TRI-STATE measured VOL1 (DC) Note TRI-STATE attained using Note power switching characteristics EPROMs require careful device decoupling recommended that least ceramic capacitor used every device between Note outputs must restricted avoid latch-up device damage Note Gate includes fixture capacitance Note connected except during programming Note Inputs outputs undershoot Note CMOS inputs
Programming Characteristics (Notes
Symbol tOES tVPS tVCS Parameter Address Setup Time Setup Time Setup Time Setup Time Data Setup Time Address Hold Time Data Hold Time
Conditions Units
Fast Programming Algorithm Flow Chart
10833
FIGURE
Functional Description
DEVICE OPERATION modes operation EPROM listed Table should noted that inputs modes levels power supplies required power supply must during three programming modes must other three modes power supply must during three programming modes other three modes Read Mode EPROM control functions both which must logically active order obtain data outputs Chip Enable PGM) power control should used device selection Output Enable (OE) output control should used gate data output pins independent device selection Assuming that addresses stable address access time (tACC) equal delay from output (tCE) Data available outputs after falling edge assuming that been addresses have been stable least tACC Standby Mode EPROM standby mode which reduces active power dissipation over from EPROM placed standby mode applying CMOS high signal input When standby mode outputs high impedance state independent input Output Disable EPROM placed output disable applying high signal input When output disable circuitry enabled except outputs high impedance state (TRI-STATE) Output OR-Typing Because EPROM usually used larger memory arrays National provided 2-line control function that accommodates this multiple memory connections 2-line control function allows lowest possible memory power dissipation complete assurance that output contention will occur most efficiently these control lines recommended that decoded used primary device selecting function while made common connection devices array connected READ line from system control This assures that deselected memory devices their power standby modes that output pins active only when data desired from particular memory device Programming CAUTION Exceeding (VPP) will damage EPROM Initially after each erasure bits EPROM ``1's'' state Data introduced selectively programming ``0's'' into desired locations Although only ``0's'' will programmed both ``1's'' ``0's'' presented data word only change ``0'' ``1'' ultraviolet light erasure EPROM programming mode when power supply required that least capacitor placed across ground suppress spurious voltage transients which damage device data programmed applied bits parallel data output pins levels required address data inputs When address data stable active program pulse applied input program pulse must applied each address location programmed EPROM programmed with Fast Programming Algorithm shown Figure Each Address programmed with series pulses until verifies good maximum pulses Most memory cells will program with single pulse EPROM must programmed with signal applied input Programming multiple EPROM parallel with same data easily accomplished simplicity programming requirments Like inputs parallel EPROM connected together when they programmed with same data level pulse applied input programs paralleled EPROM Program Inhibit Programming multiple EPROMs parallel with different data also easily accomplished Except like inputs (including parallel EPROMs common level program pulse applied EPROM's input with will program that EPROM high level input inhibits other EPROMs from being programmed
Functional Description (Continued)
Program Verify verify should performed programmed bits determine whether they were correctly programmed verify performed with must except during programming program verify AFTER PROGRAMMING Opaque labels should placed over EPROM window prevent unintentional erasure Covering window will also prevent temporary functional failure generation photo currents MANUFACTURER'S IDENTIFICATION CODE EPROM manufacturer's identification code programming When device inserted EPROM programmer socket programmer reads code then automatically calls specific programming algorithm part This automatic programming control only possible with programmers which have capability reading code Manufacturer's Identification code shown Table specifically identifies manufacturer device type code NM27C256 ``8F04'' where ``8F'' designates that made National Semiconductor ``04'' designates 256K part code accessed applying address Addresses A1-A8 A10-A16 control pins held Address held manufacturer's code held device code code read eight data pins Proper code access only guaranteed ERASURE CHARACTERISTICS erasure characteristics device such that erasure begins occur when exposed light with wavelengths shorter than approximately 4000 Angstroms should noted that sunlight certain types fluorescent lamps have wavelengths 3000 -4000 range recommended erasure procedure EPROM exposure short wave ultraviolet light which wavelength 2537 integrated dose intensity exposure time) erasure should minimum 15W-sec EPROM should placed within inch lamp tubes during erasure Some lamps have filter their tubes which should removed before erasure Table shows minimum EPROM erasure time various light intensities erasure system should calibrated periodically distance from lamp device should maintained inch erasure time increases square distance from lamp distance doubled erasure time increases factor Lamps lose intensity they When lamp changed distance changed lamp aged system should checked make certain full erasure occurring Incomplete erasure will cause symptoms that misleading Programmers components even system designs have been erroneously suspected when incomplete erasure problem SYSTEM CONSIDERATION power switching characteristics EPROMs require careful decoupling devices supply current three segments that interest system designer standby current level active current level transient current peaks that produced voltage transitions input pins magnitude these transient current peaks dependent output capacitance loading device associated transient voltage peaks suppressed properly selected decoupling capacitors recommended that least ceramic capacitor used every device between This should high frequency capacitor inherent inductance addition least bulk electrolytic capacitor should used between each eight devices bulk capacitor should located near where power supply connected array purpose bulk capacitor overcome voltage drop caused inductive effects board traces
Mode Selection
modes operation NM27C256 listed Table single power supply required read mode inputs levels except device signature TABLE Modes Selection Pins Mode Read Output Disable Standby Programming Program Verify Program Inhibit
Note
(Note
Outputs DOUT High-Z High-Z DOUT High-Z
TABLE Manufacturer's Identification Code Pins Manufacturer Code Device Code (10) (24) (19) (18) (17) (16) (15) (13) (12) (11) Data
Physical Dimensions inches (millimeters)
Window Cavity Dual-In-Line CerDIP Package Order Number NM27C256QXXX Package Number J28AQ
28-Lead Plastic One-Time-Programmable Dual-In-Line Package OrderNumber NM27C256NXXX Package Number N28B
NM27C256 144-Bit (32K High Performance CMOS EPROM
Physical Dimensions inches (millimeters) (Continued)
32-Lead Plastic Leaded Chip Carrier (PLCC) Order Number NM27C256VXXX Package Number VA32A LIFE SUPPORT POLICY NATIONAL'S PRODUCTS AUTHORIZED CRITICAL COMPONENTS LIFE SUPPORT DEVICES SYSTEMS WITHOUT EXPRESS WRITTEN APPROVAL PRESIDENT NATIONAL SEMICONDUCTOR CORPORATION used herein Life support devices systems devices systems which intended surgical implant into body support sustain life whose failure perform when properly used accordance with instructions provided labeling reasonably expected result significant injury user
National Semiconductor Corporation 2900 Semiconductor Drive 58090 Santa Clara 95052-8090 1(800) 272-9959 (910) 339-9240 National Semiconductor GmbH Livry-Gargan-Str D-82256 F4urstenfeldbruck Germany (81-41) 35-0 Telex 527649 (81-41) 35-1 National Semiconductor Japan Sumitomo Chemical Engineering Center Bldg 1-7-1 Nakase Mihama-Ku Chiba-City Ciba Prefecture (043) 299-2300 (043) 299-2500
critical component component life support device system whose failure perform reasonably expected cause failure life support device system affect safety effectiveness
National Semiconductor Hong Kong 13th Floor Straight Block Ocean Centre Canton Tsimshatsui Kowloon Hong Kong (852) 2737-1600 (852) 2736-9960
National Semiconductores Brazil Ltda Deputado Lacorda Franco 120-3A Paulo-SP Brazil 05418-000 (55-11) 212-5066 Telex 391-1131931 NSBR (55-11) 212-1181
National Semiconductor (Australia) Building Business Park Drive Monash Business Park Nottinghill Melbourne Victoria 3168 Australia 558-9999 558-9998
National does assume responsibility circuitry described circuit patent licenses implied National reserves right time without notice change said circuitry specifications

NM27C256 144-Bit (32K High Performance CMOS EPROM NM27C256 256K E

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