DS1647 Maxim, DS1647 Datasheet
DS1647
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DS1647 Summary of contents
Page 1
... V Power-Supply Tolerance CC DS1647 Only (DIP Module): Standard JEDEC Byte-Wide 128k x 8 RAM Pinout DS1647P Only (PowerCap Module Board): Surface Mountable Package for Direct Connection to PowerCap Containing Battery and Crystal Replaceable Battery (PowerCap) Power-Fail Output Pin-for-Pin Compatible with Other Densities ...
Page 2
... Data Input/Output DQ6 DQ7 GND Ground CE Active-Low Chip Enable OE Active-Low Output Enable WE Active-Low Write Enable V Power-Supply Input CC Active-Low Power-Fail Output, Open Drain. This pin requires a PFO pullup resistor for proper operation. N.C. No Connection Crystal Connections and Battery Connection V BAT DS1647/DS1647P 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 DS1647 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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... BAT <V X BAT DS1647 OE WE MODE X X Deselect X X Deselect X V Write Read Read Deselect X X Deselect DS1647/DS1647P DQ POWER High-Z Standby High-Z Standby Data In Active Data Out Active High-Z Active High-Z CMOS Standby High-Z Data-Retention Mode ...
Page 5
... The MSB Bit, B7, of the control register is the write bit. Setting the write bit like the read bit halts updates to the DS1647 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 ...
Page 6
... WRITING DATA TO RAM OR CLOCK The DS1647 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 high to low transition of WE and CE. The addresses must be held valid throughout the cycle must return inactive for a minimum of t another read or write cycle ...
Page 7
... -0.3 IL SYMBOL MIN I CC1 CC2 I CC3 2 4.0 PF SYMBOL MIN DS1647/DS1647P TYP MAX UNITS NOTES 5 +0.8 V TYP MAX UNITS NOTES 4.0 mA µA +1 µ 0.4 V 4.5 V TYP MAX UNITS NOTES ...
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... CEL 120 100 CEW t 5 AH1 t 30 AH2 t 75 WEW t WEZ DH1 t 25 DH2 DS1647/DS1647P MAX UNITS NOTES ns 120 ns 120 100 ...
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... READ CYCLE TIMING WRITE CYCLE TIMING DS1647/DS1647P ...
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... Rise Time PF (MIN) PF (MAX) CC Power-Up Expected Data-Retention Time +25°C (Oscillator On) POWER-DOWN/POWER-UP TIMING OUTPUT LOAD SYMBOL MIN TYP 300 REC DS1647/DS1647P MAX UNITS NOTES µs µs µs µs µ years 4 ...
Page 11
... All voltages are referenced to ground. 2) Typical values are at +25°C and nominal supplies. 3) Outputs are open. 4) Each DS1647 has a built-in switch that disconnects the lithium source until V user. The expected t is defined for DIP modules as a cumulative time in the absence from the time power is first applied by the user ...
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... © 2010 Maxim Integrated Products DESCRIPTION Maxim and the Dallas logo are a registered trademark of Maxim Integrated Products, Inc. DS1647/DS1647P PAGES CHANGED 1, 7 ...