DS1644-120+ Dallas Semiconductor, DS1644-120+ Datasheet
DS1644-120+
Specifications of DS1644-120+
Related parts for DS1644-120+
DS1644-120+ Summary of contents
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... Minutes, and Seconds with Leap Year Compensation Valid Up to 2100 § Power-Fail Write Protection Allows for ±10% V Power Supply Tolerance CC § DS1644 Only (DIP Module) Upward Compatible with the DS1643 Timekeeping RAM to Achieve Higher RAM Density Standard JEDEC Bytewide 32k x 8 Static RAM Pinout § ...
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... BAT DESCRIPTION The DS1644 is a 32k x 8 nonvolatile static RAM with a full function real time clock, which are both accessible in a byte-wide format. The nonvolatile timekeeping RAM is functionally equivalent to any JEDEC standard 32k x 8 SRAM. The device can also be easily substituted for ROM, EPROM and EEPROM, providing read/write nonvolatility and the addition of the real time clock function ...
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... CLOCK OPERATIONS—READING THE CLOCK While the double-buffered register structure reduces the chance of reading incorrect data, internal updates to the DS1644 clock registers should be halted before clock data is read to prevent reading of data in transition. However, halting the internal clock register updating process does not affect clock accuracy. ...
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... The MSB Bit, (B7) of the control register is the write bit. Setting the write bit like the read bit, halts updates to the DS1644 registers. The user can then load them with the correct day, date and time data in 24-hour BCD format. Resetting the write bit then transfers those values to the actual clock counters and allows normal operation to resume ...
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... WRITING DATA TO RAM OR CLOCK The DS1644 is in the write mode whenever referenced to the latter occurring high to low transition of throughout the cycle another read or write cycle ...
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... V level of the internal battery supply, power input is switched from the V clock activity, RAM, and clock data are maintained from the battery until V level. > 4.5 volts) the DS1644 can be accessed as described above with CC is below the power-fail point V CC signal ...
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ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground……………………………………………..-0.3V to +7.0V Storage Temperature……………………………………………………...-40°C to +85°C, Noncondensing Soldering Temperature……………………………..…+260°C for 10 seconds (DIP Package) (See Note 7) This is a stress rating only and functional operation of the device ...
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AC ELECTRICAL CHARACTERISTICS PARAMETER Read Cycle Time Address Access Time Access Time CE Data Off Time CE Output Enable Access Time Output Enable Data Off Time Output Enable to DQ Low Low-Z CE Output Hold from Address Write ...
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... DS1644 READ CYCLE TIMING DS1644 WRITE CYCLE TIMING ...
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POWER-DOWN/POWER-UP TIMING OUTPUT LOAD ...
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... In addition, for the PowerCap version: a. Dallas Semiconductor recommends that PowerCap Module bases experience one pass through solder reflow oriented with the label side up (“live - bug”). b. Hand soldering and touch-up: Do not touch or apply the soldering iron to leads for more than 3 (three) seconds ...
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... PACKAGE INFORMATION (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo DS1644 28-PIN PACKAGE DS1644P .) PKG 28-PIN DIM MIN A IN. 1.470 MM 37.34 B IN. 0.715 MM 18.16 C IN. 0.335 MM 8.51 D IN. 0.075 MM 1 ...
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... DS1644P WITH DS9034PCX ATTACHED RECOMMENDED POWERCAP MODULE LAND PATTERN Maxim/Dallas Semiconductor cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim/Dallas Semiconductor product. No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time. ...