DS1747 Maxim, DS1747 Datasheet
DS1747
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DS1747 Summary of contents
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... DQ7 DQ6 DQ0 14 19 DQ1 DQ5 DQ2 15 18 DQ4 17 GND 16 DQ3 Encapsulated DIP (512k Maxim 33 2 DS1747P GND X2 18 ...
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PIN DESCRIPTION EDIP PowerCap ...
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... DESCRIPTION The DS1747 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 512k x 8 nonvolatile static RAM. User access to all registers within the DS1747 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour binary-coded decimal (BCD) format ...
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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 DS1747 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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... As shown in Table 2, bit 7 of the century register is the write bit. Setting the write bit to a one, like the read bit, halts updates to the DS1747 registers. The user can then load them with the correct day, date and time data in 24-hour format. Resetting the write bit to a zero then transfers those values to the actual clock counters and allows normal operation to resume ...
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... OH WRITING DATA TO RAM OR CLOCK The DS1747 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 addresses must be held valid throughout the cycle must return inactive for a minimum of t write cycle ...
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... The DS1747 has a lithium power source that is designed to provide energy for clock activity, and clock and RAM data retention when the V is sufficient to power the DS1747 continuously for the life of the equipment in which it is installed. For specification purposes, the life expectancy is 10 years at +25°C with the internal clock oscillator running in the absence of V power ...
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... Soldering Temperature (reflow, PowerCap) .................................................................................................. +260°C This is a stress rating only and functional operation of the device at these or any other condition 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 device reliability. ...
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DC ELECTRICAL CHARACTERISTICS = 3.3V ±10 Over the Operating Range PARAMETER Active Supply Current TTL Standby Current ( CMOS Standby Current ( CE ≥ 0.2V) CC Input Leakage ...
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AC CHARACTERISTICS—READ CYCLE (3.3V 3.3V ±10 Over the Operating Range PARAMETER Read Cycle Time Address Access Time Low Access Time CE Data Off Time Low-Z OE ...
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AC CHARACTERISTICS—WRITE CYCLE (5V 5.0V ±10 Over the Operating Range PARAMETER Write Cycle Time Address Setup Time WE Pulse Width CE Pulse Width Data Setup Time Data Hold Time Data Hold Time Address Hold ...
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... WRITE CYCLE TIMING DIAGRAM, WRITE-ENABLE CONTROLLED WRITE CYCLE TIMING DIAGRAM, CHIP-ENABLE CONTROLLED DS1747/DS1747P Y2K-Compliant, Nonvolatile Timekeeping RAMs ...
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POWER-UP/DOWN AC CHARACTERISTICS (5V 5.0V ±10 Over the Operating Range PARAMETER Before Power-Down V Fall Time PF(MAX) V PF(MIN) V Fall Time ...
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POWER-UP/DOWN CHARACTERISTICS (3.3V 3.3V ±10 Over the Operating Range PARAMETER Before H Power-Down V Fall Time PF(MAX) V PF(MIN) V Rise Time ...
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... Battery switchover occurs at the lower of either the battery terminal voltage Data-retention time is at +25°C. 6) Each DS1747 has a built-in switch that disconnects the lithium source until the user first applies V The expected t is defined for DIP modules and assembled PowerCap modules as accumulative time ...
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... 2012 Maxim Integrated Products DS1747/DS1747P Y2K-Compliant, Nonvolatile Timekeeping RAMs DESCRIPTION Maxim is a registered trademark of Maxim Integrated Products ...