Datasheet

ManualsBrandsMaxim ManualsMemory ICsNV-RAM 8 k x 8 Bit EDIL-28

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FEATURES

 Real-Time Clock Keeps Track of Hundredths

of Seconds, Seconds, Minutes, Hours, Days,

Date of the Month, Months, and Years

 8K x 8 NV SRAM Directly Replaces

Volatile Static RAM or EEPROM

 Embedded Lithium Energy Cell Maintains

Calendar Operation and Retains RAM Data

 Watch Function is Transparent to RAM

Operation

 Automatic Leap Year Compensation Valid

Up to 2100

 Lithium Energy Source is Electrically

Disconnected to Retain Freshness Until

Power is Applied for the First Time

 Standard 28-Pin JEDEC Pinout

 Full ±10% Operating Range

 Accuracy is Better than ±1 Minute/Month at

+25°C

 Over 10 Years of Data Retention in the

Absence of Power

 Available in 120ns Access Time

 Underwriters Laboratories (UL) Recognized

(www.maxim-ic.com/qa/info/ul)

PIN CONFIGURATION

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

DS1243Y-120+

0°C to +70°C

28 EDIP (0.720a)

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

Encapsulated Package

(720-Mil Extended)

DQ0

DQ1

GND

DQ2

N.C.

A11

A10

DQ7

DQ6

DQ5

DQ3

DQ4

A12

RST

DS1243Y

TOP VIEW

DS1243Y

64K

NV SRAM with Phantom Clock

19-6076; Rev 11/11

Summary of content (14 pages)

PAGE 1
9-6076; Rev 11/11 DS1243Y 64K NV SRAM with Phantom Clock PIN CONFIGURATION FEATURES             Real-Time Clock Keeps Track of Hundredths of Seconds, Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years 8K x 8 NV SRAM Directly Replaces Volatile Static RAM or EEPROM Embedded Lithium Energy Cell Maintains Calendar Operation and Retains RAM Data Watch Function is Transparent to RAM Operation Automatic Leap Year Compensation Valid Up to 2100 Lithium Energy Source is Electrically
PAGE 2
DS1243Y PIN DESCRIPTION PIN NAME 1 RST 2 3 4 5 6 7 8 9 10 23 21 24 25 11 12 13 15 16 17 18 19 20 22 26 27 28 14 A12 A7 A6 A5 A4 A3 A2 A1 A0 A11 A10 A9 A8 DQ0 DQ1 DQ2 DQ3 DQ4 DQ5 DQ6 DQ7 CE OE N.C. WE VCC GND FUNCTION Active-Low Reset Input. This pin has an internal pullup resistor connected to VCC.
PAGE 3
DS1243Y RAM READ MODE The DS1243Y executes a read cycle whenever WE (Write Enable) is inactive (high) and CE (Chip Enable) is active (low). The unique address specified by the 13 address inputs (A0–A12) defines which of the 8192 bytes of data is to be accessed. Valid data will be available to the eight data output drivers within tACC (Access Time) after the last address input signal is stable, providing that CE and OE (Output Enable) access times and states are also satisfied.
PAGE 4
DS1243Y PHANTOM CLOCK OPERATION Communication with the Phantom Clock is established by pattern recognition on a serial bit stream of 64 bits which must be matched by executing 64 consecutive write cycles containing the proper data on DQ0. All accesses which occur prior to recognition of the 64–bit pattern are directed to memory. After recognition is established, the next 64 read or write cycles either extract or update data in the Phantom Clock, and memory access is inhibited.
PAGE 5
DS1243Y PHANTOM CLOCK REGISTER DEFINITION Figure 1 NOTE: THE PATTERN RECOGNITION IN HEX IS C5, 3A, A3, 5C, C5, 3A, A3, 5C. THE ODDS OF THIS PATTERN BEING ACCIDENTALLY DUPLICATED AND CAUSING INADVERTENT ENTRY TO THE PHANTOM CLOCK IS LESS THAN 1 IN 1019. THIS PATTERN IS SENT TO THE PHANTOM CLOCK LSB TO MSB.
PAGE 6
DS1243Y PHANTOM CLOCK REGISTER DEFINITION Figure 2 AM-PM/12/24 MODE Bit 7 of the hours register is defined as the 12- or 24-hour mode select bit. When high, the 12-hour mode is selected. In the 12-hour mode, bit 5 is the AM/PM bit with logic high being PM. In the 24-hour mode, bit 5 is the 20-hour bit (20–23 hours). OSCILLATOR AND RESET BITS Bits 4 and 5 of the day register are used to control the RESET and oscillator functions. Bit 4 controls the RESET (pin 1).
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DS1243Y ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground……………………………………………..-0.3V to +6.0V Operating Temperature Range……………………………………………...0°C to +70°C (noncondensing) Storage Temperature Range……………………………………………...-40°C to +85°C (noncondensing) Lead Temperature (soldering, 10s)……… . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +260°C Note: EDIP is wave or hand-soldered only.
PAGE 8
DS1243Y MEMORY AC ELECTRICAL CHARACTERISTICS (VCC = 5.0V ±10%, TA = 0°C to +70°C.
PAGE 9
DS1243Y PHANTOM CLOCK AC ELECTRICAL CHARACTERISTICS (VCC = 4.5V to 5.5V, TA = 0°C to +70°C.
PAGE 10
DS1243Y MEMORY READ CYCLE (NOTE 1) MEMORY WRITE CYCLE 1 (NOTES 2, 6, AND 7) 10 of 14
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DS1243Y MEMORY WRITE CYCLE 2 (NOTES 2 AND 8) RESET FOR PHANTOM CLOCK READ CYCLE TO PHANTOM CLOCK 11 of 14
PAGE 12
DS1243Y WRITE CYCLE TO PHANTOM CLOCK POWER-DOWN/POWER-UP CONDITION 12 of 14
PAGE 13
DS1243Y NOTES: 1. WE is high for a read cycle. 2. OE = VIH or VIL. If OE = VIH during write cycle, the output buffers remain in a high impedance state. 3. tWP is specified as the logical AND of CE and WE . tWP is measured from the latter of CE or WE going low to the earlier of CE or WE going high. 4. tDH, tDS are measured from the earlier of CE or WE going high. 5. These parameters are sampled with a 50pF load and are not 100% tested. 6.
PAGE 14
DS1243Y REVISION HISTORY REVISION DATE 11/11 DESCRIPTION Updated the Features, Ordering Information, AM-PM/12/24 MODE, and Absolute Maximum Ratings sections PAGES CHANGED 1, 6, 7 14 of 14 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.