Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsIntegrated Circuits (ICs)Timer IC t- real time clock Clock/calendar PowerCap 34 (modules)

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FEATURES

 Integrates NV SRAM, Real-Time Clock,

Crystal, Power-Fail Control Circuit and

Lithium Energy Source

 Clock Registers are Accessed Identically to

the Static RAM. These Registers are

Resident in the Eight Top RAM Locations

 Totally Nonvolatile with Over 10 Years of

Operation in the Absence of Power

 BCD-Coded Year, Month, Date, Day, Hours,

Minutes, and Seconds with Leap Year

Compensation Valid Up to 2100

 Power-Fail Write Protection Allows for

±10% V

Power Supply Tolerance

 DS1646 only (DIP Module)

Standard JEDEC Bytewide 128k x 8 RAM

Pinout

 DS1646P 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

of DS164xP Timekeeping RAM

Underwriters Laboratories (UL) Recognized

PIN CONFIGURATIONS

ORDERING INFORMATION

PART

VOLTAGE

RANGE (V)

TEMP RANGE PIN-PACKAGE TOP MARK

DS1646-120+

5.0

0°C to +70°C

32 EDIP (0.740a)

DS1646+120

DS1646P-120+

5.0

0°C to +70°C

34 PowerCap*

DS1646P+120

+Denotes a lead(Pb)-free/RoHS-compliant package.

DS9034-PCX+ or DS9034I-PCX+ required (must be ordered separately).

A “+" indicates a lead(Pb)-free product. The top mark will include a “+" symbol on lead(Pb)-free devices.

N.C.

A15

A16

PFO

DQ7

DQ6

DQ5

DQ4

DQ3

DQ2

DQ1

DQ0

GND

N.C.

A14

A13

A12

A11

A10

N.C.

X1 GND

BAT

34-Pin PowerCap Module Board

(Uses DS9034PCX+ or DS9034I-PCX+ PowerCap)

32-Pin Encapsulated Package

A14

DQ1

DQ0

A15

N.C.

A13

A11

A10

DQ7

DQ5

DQ6

A16

A12

N.C.

DQ2

GND

DQ4

DQ3

DS1646/DS1646P

Nonvolatile Timekeeping RAM

www.maxim-ic.com

19-5595; Rev 10/10

Summary of content (12 pages)

PAGE 1
9-5595; Rev 10/10 DS1646/DS1646P Nonvolatile Timekeeping RAM www.maxim-ic.com FEATURES        Integrates NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit and Lithium Energy Source Clock Registers are Accessed Identically to the Static RAM.
PAGE 2
DS1646/DS1646P PIN DESCRIPTION PDIP 1, 30 2 3 4 5 6 7 8 9 10 11 12 25 26 27 28 13 14 15 17 18 19 20 21 16 22 23 24 29 31 32 PIN PowerCap 1, 33, 34 3 32 30 25 24 23 22 21 20 19 18 29 27 26 31 16 15 14 13 12 11 10 9 17 8 28 7 6 2 5 — 4 — NAME N.C.
PAGE 3
DS1646/DS1646P DESCRIPTION The DS1646 is a 128k 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 128k 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. The real time clock information resides in the eight uppermost RAM locations.
PAGE 4
DS1646/DS1646P BLOCK DIAGRAM DS1646 Figure 1 TRUTH TABLE DS1646 Table 1 VCC <4.5V >VBAT VIH X VIL VIL VIL X X X X VIL VIH X X X VIL VIH VIH X MODE DESELECT DESELECT WRITE READ READ DESELECT
PAGE 5
DS1646/DS1646P CLOCK ACCURACY (DIP MODULE) The DS1646 is guaranteed to keep time accuracy to within ±1 minute per month at 25°C. The RTC is calibrated at the factory by Dallas Semiconductor using nonvolatile tuning elements, and does not require additional calibration. For this reason, methods of field clock calibration are not available and not necessary.
PAGE 6
DS1646/DS1646P WRITING DATA TO RAM OR CLOCK The DS1646 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. CE or WE must return inactive for a minimum of tWR prior to the initiation of another read or write cycle. Data in must be valid tDS prior to the end of write and remain valid for tDH afterward.
PAGE 7
DS1646/DS1646P ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground……………………………………………..-0.3V to +6.0V Storage Temperature Range EDIP..........………………………………….........................................……………-40°C to +85°C PowerCap......…………………………………....................................……………-55°C to +125°C Lead Temperature (soldering, 10s) ……........................................................................................... +260°C Note: EDIP is wave or hand soldered only.
PAGE 8
DS1646/DS1646P AC ELECTRICAL CHARACTERISTICS PARAMETER Read Cycle Time Address Access Time CE Access Time CE Data Off Time Output Enable Access Time Output Enable Data Off Time Output Enable to DQ Low-Z CE to DQ Low-Z Output Hold from Address Write Cycle Time Address Setup Time CE Pulse Width Address Hold from End of Write Write Pulse Width WE Data Off Time WE or CE Inactive Time Data Setup Time Data Hold Time High SYMBOL tRC tAA tCEA tCEZ tOEA tOEZ tOEL tCEL tOH tWC tAS tCEW tAH1 tAH2 tWEW tWEZ tWR tDS
PAGE 9
DS1646/DS1646P DS1646 READ CYCLE TIMING DS1646 WRITE CYCLE TIMING 9 of 12
PAGE 10
DS1646/DS1646P POWER-DOWN/POWER-UP TIMING OUTPUT LOAD 10 of 12
PAGE 11
DS1646/DS1646P NOTES: 1) All voltages are referenced to ground. 2) Typical values are at 25°C and nominal supplies. 3) Outputs are open. 4) Data retention time is at 25°C 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. 5) tAH1, tDH1 are measured from WE going high. 6) tAH2, tDH2 are measured from CE going high.
PAGE 12
DS1646/DS1646P REVISION HISTORY REVISION DESCRIPTION DATE Updated the Ordering Information table; updated the storage, lead, 10/10 and soldering information in the Absolute Maximum Ratings section PAGES CHANGED 1, 7 12 of 12 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.