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DS1249Y/AB

2048K Nonvolatile SRAM

DS1249Y/AB

021497 1/9

FEATURES

• 10 years minimum data retention in the absence of

external power

• Data is automatically protected during power loss

• Unlimited write cycles

• Low–power CMOS operation

• Read and write access times as fast as 70 ns

• Lithium energy source is electrically disconnected to

retain freshness until power is applied for the first time

• Full ± 10% V

operating range (DS1249Y)

• Optional ± 5% V

operating range (DS1249AB)

• Optional industrial temperature range of –40°C to

+85°C, designated IND

• JEDEC standard 32–pin DIP package

PIN ASSIGNMENT

A15

A17

A13

A11

A10

DQ7

DQ6

DQ5

DQ4

DQ3

A16

A14

A12

DQ0

DQ1

DQ2

GND

32–PIN ENCAPSULATED PACKAGE

740 MIL EXTENDED

PIN DESCRIPTION

A0 – A17 – Address Inputs

DQ0 – DQ7 – Data In/Data Out

– Chip Enable

WE – Write Enable

OE – Output Enable

– Power (+5V)

GND – Ground

NC – No Connect

DESCRIPTION

The DS1249 2048K Nonvolatile SRAMs are

2,097,152–bit, fully static, nonvolatile SRAMs orga-

nized as 262,144 words by 8 bits. Each NV SRAM has a

self–contained lithium energy source and control cir-

cuitry which constantly monitors V

for an out–of–tol-

erance condition. When such a condition occurs, the

lithium energy source is automatically switched on and

write protection is unconditionally enabled to prevent

data corruption. There is no limit on the number of write

cycles which can be executed and no additional support

circuitry is required for microprocessor interfacing.

1 2 3 4 5 6 7 8 9

Resumo do Conteúdo

Página 1 - 2048K Nonvolatile SRAM

Página 2 - FRESHNESS SEAL

DS1249Y/AB021497 2/9READ MODEThe DS1249 devices execute a read cycle wheneverWE (Write Enable) is inactive (high) and CE (Chip En-able) and OE (Output

Página 3 - 021497 3/9

DS1249Y/AB021497 3/9ABSOLUTE MAXIMUM RATINGS*Voltage on Any Pin Relative to Ground –0.3V to +7.0VOperating Temperature 0°C to 70°C, –40°C to +85°C for

Página 4 - : See Note 10) (V

DS1249Y/AB021497 4/9(VCC=5V ± 5% for DS1249AB)AC ELECTRICAL CHARACTERISTICS (tA: See Note 10) (VCC=5V ±10% for DS1249Y)PARAMETERSYMBOLDS1249AB–70DS12

Página 5 - WRITE CYCLE 1

DS1249Y/AB021497 5/9READ CYCLEtRCtACCVIHVILVIHVILVIHVILtOHVIHtODtODVIHVOHVOLVOHVOLtCOEtCOEOUTPUTDATA VALIDDOUTOEADDRESSESVIHVIHtOEVILVILCE tCOSEE NOTE

Página 6 - POWER–DOWN/POWER–UP CONDITION

VCCVTP3.0VtFtPDtRtRECtDRBACKUP CURRENTSUPPLIED FROMLITHIUM BATTERYCE,WESEE NOTE 11tPUDS1249Y/AB021497 6/9WRITE CYCLE 2tWCVILVIHVILVIHVILVIHADDRESSESC

Página 7 - 021497 7/9

DS1249Y/AB021497 7/9POWER–DOWN/POWER–UP TIMING (tA: See Note 10)PARAMETER SYMBOL MIN TYP MAX UNITS NOTESVCC Fail Detect to CE and WEInactivetPD1.5 µs

Página 8 - ORDERING INFORMATION

DS1249Y/AB021497 8/9DC TEST CONDITIONSOutputs OpenCycle = 200 ns for operating currentAll voltages are referenced to groundAC TEST CONDITIONSOutput Lo

Página 9

A1CFGKDHBEJDS1249Y/AB021497 9/9DS1249Y/AB NONVOLATILE SRAM, 32–PIN 740 MIL EXTENDED MODULEPKG 32–PINDIM MIN MAXA IN.MM2.08052.832.10053.34B IN.MM0.715

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Rainbow-electronics DS1249Y_AB Manual do Utilizador

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