DS1243 Dallas Semiconductor, DS1243 Datasheet
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DS1243
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DS1243 Summary of contents
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... DESCRIPTION The DS1243Y 64K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 8192 words by 8 bits) with a built–in real time clock. The DS1243Y has a self–contained lithium energy source and control circuitry which constantly monitors V condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent corrupted data in both the memory and real time clock ...
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... RAM to retain data. During power–up, when V switching circuit connects external V RAM operation can resume after V FRESHNESS SEAL Each DS1243Y is shipped from Dallas Semiconductor with its lithium energy source disconnected, insuring full energy capacity. When V source is enabled for battery backup operation. PHANTOM CLOCK OPERATION Communication with the Phantom Clock is established by pattern recognition on a serial bit stream of 64 bits which must be matched by executing 64 consecutive write cycles containing the proper data on DQ0 ...
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... Write Enable ( OE control of the Phantom Clock starts the pattern recognition sequence by control of the SmartWatch. These 64 write cycles are used only to gain Initially, a read cycle to any memory WE DS1243Y ...
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... PHANTOM CLOCK REGISTER DEFINITION Figure 1 NOTE: The pattern recognition in Hex is C5, 3A, A3, 5C, C5, 3A, A3, 5C. The odds of this pattern being accidentally duplicated and causing inadvertent entry to the Phantom Clock is less than pattern is sent to the Phantom Clock LSB to MSB DS1243Y 19 . This ...
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... Registers and 6 contain one or more bits which will always read logic 0. When writing these locations, either a logic acceptable. and oscillator functions. Bit 4 controls the RESET bit is set to logic 1, the RESET pin will cause the Phantom Clock to abort data transfer RESET input pin is ignored. When the DS1243Y RESET ...
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... SYMBOL MIN TYP 5.0 CCS1 I 3.0 CCS2 I CC01 V 4.25 TP SYMBOL MIN TYP I DS1243Y ( MAX UNITS NOTES 10%) CC MAX UNITS NOTES + ...
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... Gate 0–3V 1.5V 1. DS1243Y = 5.0V 10%) CC DS1243Y MIN MAX UNITS NOTES 200 ns 200 ns 100 ns 200 100 200 ns 150 ...
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... IH t REC SYMBOL MIN (0°C to 70° 4.5 to 5.5V) CC TYP MAX UNITS ns 100 ns 100 TYP MAX UNITS TYP MAX UNITS years DS1243Y NOTES NOTES = 25°C) NOTES 9 ...
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... MEMORY READ CYCLE (NOTE 1) MEMORY WRITE CYCLE 1 (NOTES 2, 6, AND DS1243Y ...
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... MEMORY WRITE CYCLE 2 (NOTES 2 AND 8) RESET FOR PHANTOM CLOCK READ CYCLE TO PHANTOM CLOCK DS1243Y ...
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... WRITE CYCLE TO PHANTOM CLOCK POWER-DOWN/POWER-UP CONDITION DS1243Y ...
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... IH and . t is measured from the latter going high going high low transition in Write WE high transition, the output WE low transition, CE with the clock oscillator DS1243Y or WE ...
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... DS1243Y 28–PIN EXTENDED BOTTOM 720-MIL BODY WIDTH (DIMENSION B) PKG 28-PIN DIM MIN A IN. 1.520 MM 38.61 B IN. 0.695 MM 17.65 C IN. 0.395 MM 10.03 D IN. 0.100 MM 2.54 E IN. 0.017 MM 0.43 F IN. 0.120 MM 3.05 G IN. 0.090 MM 2.29 H IN. 0.590 MM 14.99 J IN. 0.008 MM 0.20 K IN. 0.015 MM 0. DS1243Y MAX 1.540 39.12 0.720 1.29 0.415 10.54 0.130 3.30 0.030 ...