DS1742-85 MAXIM [Maxim Integrated Products], DS1742-85 Datasheet
DS1742-85
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DS1742-85 Summary of contents
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... DQ5 11 14 DQ2 DQ4 12 13 GND DQ3 ENCAPSULATED DIP PIN-PACKAGE TOP MARK** 24 EDIP (0.740a) DS1742-85 24 EDIP (0.740a) DS1742-85+ 24 EDIP (0.740a) DS1742-100 24 EDIP (0.740a) DS1742-100+ 24 EDIP (0.740a) DS1742-100IND 24 EDIP (0.740a) DS1742-100IND+ 24 EDIP (0.740a) DS1742W-120 24 EDIP (0.740a) DS1742W-120+ 24 EDIP (0.740a) DS1742W-150 24 EDIP (0.740a) ...
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... DESCRIPTION The DS1742 is a full-function, year 2000-compliant (Y2KC), real-time clock/calendar (RTC) and nonvolatile static RAM. User access to all registers within the DS1742 is accomplished with a bytewide 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 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 DS1742 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. Updating is halted when written into the read bit, bit 6 of the century register, see Table 2 ...
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... As shown in Table 2, bit 7 of the century register is the write bit. Setting the write bit like the read bit, halts updates to the DS1742 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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... indeterminate until the next address access. WRITING DATA TO RAM OR CLOCK The DS1742 is in the write mode whenever write is referenced to the latter occurring transition of valid throughout the cycle. initiation of another read or write cycle. Data in must be valid t remain valid for t afterward ...
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... BATTERY LONGEVITY The DS1742 has a lithium power source that is designed to provide energy for clock activity, and clock and RAM data retention when the V internal power supply is sufficient to power the DS1742 continuously for the life of the equipment in which it is installed. For specification purposes, the life expectancy is 10 years at 25° ...
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ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground……………………………………..-0.3V to +6.0V Storage Temperature Range………………………………………………………...-40°C to +85°C Soldering Temperature (EDIP, leads)..……………………..+260°C for 10 seconds (See Note 7) This is a stress rating only and functional operation of the device ...
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DC ELECTRICAL CHARACTERISTICS = 3.3V ±10%, Over the operating range PARAMETER Active Supply Current TTL Standby Current ( CMOS Standby Current ≥ 0.2V Input Leakage Current (any input) Output ...
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AC CHARACTERISTICS—READ CYCLE (3.3V) = 3.3V ±10%, Over the operating range PARAMETER Read Cycle Time Address Access Time to DQ Low-Z CE Access Time CE Data Off time Low-Z OE Access Time OE Data Off ...
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AC CHARACTERISTICS—WRITE CYCLE (5V) = 5.0V ±10%, Over the operating range PARAMETER SYMBOL Write Cycle Time Address Access Time Pulse Width WE Pulse Width CE Data Setup Time Data Hold time Address Hold Time Data Off Time WE ...
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WRITE CYCLE TIMING DIAGRAM—WRITE-ENABLE CONTROLLED WRITE CYCLE TIMING DIAGRAM—CHIP-ENABLE CONTROLLED ...
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POWER-UP/POWER-DOWN CHARACTERISTICS (5V) = 5.0V ±10%, Over the operating range PARAMETER Before Power-Down Fall Time PF(MAX) V Fall Time PF(MIN) V Rise ...
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POWER-UP/POWER-DOWN CHARACTERISTICS (3.3V) = 3.3V ±10%, Over the operating range PARAMETER Before Power Down V Fall Time PF(MAX) V Rise Time PF(MIN) Power-Up ...
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... Outputs are open. 4) Battery switchover occurs at the lower of either the battery voltage Data retention time is at 25°C. 6) Each DS1742 has a built-in switch that disconnects the lithium source until V applied by the user. The expected t starting from the time power is first applied by the user. ...
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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/packages ...
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... Ordering Information table. Removed reference to J-STD-020 and indicated the lead 060706 soldering temperature of +260°C for 10 seconds max. Added DS1742-85, DS1742-85+ to the Ordering Information 022207 table; removed DS1742P-100+ (PowerCap) package. Removed the –70 ordering numbers from the Ordering 102808 Information table. ...