DS1243 Maxim Integrated Products, DS1243 Datasheet

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DS1243

Manufacturer Part Number
DS1243
Description
DS124364kSRAM,
Manufacturer
Maxim Integrated Products
Datasheet

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GENERAL DESCRIPTION
The DS1254 is a fully nonvolatile static RAM (NV SRAM)
(organized as 2M words by 8 bits) with built-in real-time
clock. It has a self-contained lithium energy source and
control circuitry that constantly monitors V
tolerance condition. When such a condition occurs, the
DS1254 makes use of an attached DS3800 battery cap to
maintain clock information and preserve stored data while
protecting that data by disallowing all memory accesses.
Additionally, the DS1254 has dedicated circuitry for
monitoring the status of an attached DS3800 battery cap.
FEATURES
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APPLICATIONS
Telecom Switches
Routers
RAID Systems
ORDERING INFORMATION
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.
www.maxim-ic.com
DS1254WB-150
DS1254WB2-150
DS1254YB-100
DS1254YB2-100
Real-Time Clock (RTC) Keeps Track of Hundredths of
Seconds, Seconds, Minutes, Hours, Days, Date,
Months, and Years with Automatic Leap-Year
Compensation Valid Up to the Year 2100
2M x 8 NV SRAM
Watch Function is Transparent to RAM Operation
Automatic Data Protection During Power Loss
Unlimited Write-Cycle Endurance
Surface-Mountable BGA Module Construction
Over 10 Years of Data Retention in the Absence of
Power
Battery Monitor Checks Remaining Capacity Daily
+3.3V or +5V Operation
Underwriters Laboratory (UL) Recognized
(www.maxim-ic.com/qa/info/ul/)
PART
TEMP RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
PIN-PACKAGE
40mm BGA
40mm BGA
40mm BGA
40mm BGA
CC
for an out-of-
2M x 8 NV SRAM with Phantom Clock
1 of 17
RANGE (V)
VOLTAGE
PACKAGE OUTLINE
TYPICAL OPERATING CIRCUIT
3.3
3.3
5.0
5.0
(For Reference Only, Not to Scale)
Component placement may vary.
DS1254W-150
DS1254W-150
DS1254Y-100
DS1254Y-100
TOP MARK
Side -A- Shown
REV: 070705
DS1254

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DS1243 Summary of contents

Page 1

GENERAL DESCRIPTION The DS1254 is a fully nonvolatile static RAM (NV SRAM) (organized as 2M words by 8 bits) with built-in real-time clock. It has a self-contained lithium energy source and control circuitry that constantly monitors V tolerance condition. ...

Page 2

DETAILED DESCRIPTION The DS1254 is a fully nonvolatile static RAM (NV SRAM) (organized as 2M words by 8 bits) with built-in real-time clock. It has a self-contained lithium energy source and control circuitry that constantly monitors V tolerance condition. When ...

Page 3

RAM READ MODE The DS1254 executes a read cycle whenever WE is inactive (high) and CE is active (low). The unique address specified by the 21 address inputs (A0–A20) defines which of the 2MB of data accessed. ...

Page 4

The next 64 cycles will cause the phantom clock to either receive or transmit data on DQ0, depending on the level of the OE pin or the WE pin. Cycles ...

Page 5

Figure 3. Phantom Clock Register Definition ...

Page 6

AM/PM/12/24 MODE Bit 7 of the hours register is defined as the 12-hour 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. ...

Page 7

ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground Operating Temperature Range Storage Temperature Range Soldering Temperature Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and ...

Page 8

CAPACITANCE ° + PARAMETER Input Capacitance A18 Input Capacitance: A19 to A20 I/O Capacitance: DQ0 to DQ7 Output Capacitance ELECTRICAL CHARACTERISTICS ° = 5.0V ±10 ...

Page 9

AC ELECTRICAL CHARACTERISTICS ° 3.3V ±10 + PARAMETER Read Cycle Time Address Access Time OE to Output Valid CE to Output Valid Output Active Output High-Z from ...

Page 10

BATTERY WARNING TIMING ° 5.0V ±10 + PARAMETER Battery Test Cycle Battery Test Pulse Width Battery Test to BW Active Valid to BW Valid TEST CONDITIONS Output Load: ...

Page 11

Figure 5. Memory Write Cycle Timing, Write-Enable Controlled (Notes 10, 11, 12, and 13) ADDRESS CE WE DQ0–DQ7 Figure 6. Memory Write Cycle Timing, Chip-Enable Controlled (Notes 10, 11, 12, and 13) ADDRESS CE ...

Page 12

Figure 7. Read Cycle to Phantom Clock DQ0 Figure 8. Write Cycle to Phantom Clock DQ0 COE ...

Page 13

Figure 9. Power-Up/Power-Down Waveform Timing (Note 14 PF(max) V PF(min) V BAT Figure 10. Battery Warning Detection (Note BAT BATTERY TEST ACTIVE ...

Page 14

NOTES: 1) Voltage referenced to ground. 2) These parameters are sampled with a 50pF load and are not 100% tested open-drain output and, as such, cannot source current. An external pullup resistor should be connected to ...

Page 15

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/DallasPackInfo.) PKG MIN IN 1.570 1.580 A MM 39.88 40.13 IN 1.570 1.580 B MM 39.88 ...

Page 16

PACKAGE INFORMATION (continued) (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/DallasPackInfo.) DS1254 with Attached DS3800 Battery Cap PKG MIN A IN 1.656 MM 42.06 B ...

Page 17

... The Maxim logo is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Dallas Semiconductor Corporation. ...

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