DS1643-150 Dallas Semiconductor, DS1643-150 Datasheet
DS1643-150
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DS1643-150 Summary of contents
Page 1
... DESCRIPTION The DS1643 nonvolatile static RAM with a full function real time clock which are both accessible in a bytewide format. The nonvolatile time keeping RAM is pin and function equivalent to any JEDEC standard SRAM. The device can also be easily substituted ...
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... However, the internal clock reg- isters of the double buffered system continue to update so that the clock accuracy is not affected by the access of data. All of the DS1643 registers are updated simul- taneously after the clock status is reset. Updating is within a second after the read bit is written to zero. ...
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... The 8–bit of the control register is the write bit. Setting the write bit to a one, like the read bit, halts updates to the DS1643 registers. The user can then load them with the correct day, date and time data in 24 hour BCD for- mat ...
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... X = UNUSED WRITING DATA TO RAM OR CLOCK The DS1643 is in the write mode whenever WE and CE are in their active state. The start of a write is referenced to the latter occurring transition CE. The ad- dresses must be held valid throughout the cycle after the last address WE must return inactive for a minimum of t the initiation of another read or write cycle ...
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... DS1643 will be much longer than 10 years since no internal lithium battery energy is con- sumed when V tions, the life expectancy of the DS1643 will be approxi- mately equal to the shelf life (expected useful life of the lithium battery with no load attached) of the lithium bat- tery which may prove long as 20 years ...
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... DS1643 ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability ...
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... 5.0V CC DS1643–150 MIN MAX UNITS UNITS 150 ns 150 ns 150 120 150 120 150 110 MAX UNITS DS1643 10%) NOTES NOTES NOTES 041697 7/11 ...
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... Fall Time (Min Rise Time CC V (Min (Max Rise Time CC Power–Up Expected Data Retention Time (Oscillator On) DS1643 READ CYCLE TIMING READ t RC A0–A12 t CEA CE t CEL t OEA OEL DQ0–DQ7 041697 8/11 SYMBOL MIN TYP ...
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... DS1643 WRITE CYCLE TIMING WRITE t WC A0–A12 CEW WEW WE t CEZ t DS VALID DQ0– OUT DQ7 POWER–DOWN/POWER–UP TIMING (MAX BATT WRITE AH2 DH2 VALID IN (MIN ...
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... DS1643 NOTES: 1. All voltages are referenced to ground. 2. Typical values are and nominal supplies. 3. Outputs are open. 4. Data retention time and is calculated from the date code on the device package. The date code XXYY is the year followed by the week of the year in which the device was manufactured. For example, 9225, would mean the 25th week of 1992 ...
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... DS1643 28–PIN PACKAGE PKG 28–PIN DIM MIN MAX A IN. 1.470 1.490 MM 37.34 37.85 B IN. 0.675 0.740 MM 17.75 18.80 C IN. 0.335 0.355 MM 8.51 9.02 D IN. 0.075 0.105 MM 1.91 2.67 E IN. 0.015 0.030 MM 0.38 0.76 F IN. 0.140 0.180 MM 3.56 4.57 G IN. 0.090 0.110 MM 2.29 2.79 H IN. 0.590 0.630 MM 14.99 16.00 J IN. 0.010 0.018 MM 0.25 0.45 K IN. ...