DS1244 Maxim, DS1244 Datasheet

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DS1244

Manufacturer Part Number
DS1244
Description
The DS1244 256k NV SRAM with a Phantom clock is a fully static nonvolatile RAM (NV SRAM) (organized as 32k words by 8 bits) with a built-in real-time clock
Manufacturer
Maxim
Datasheet

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FEATURES
 Real-Time Clock (RTC) Keeps Track of
 32K x 8 NV SRAM Directly Replaces
 Embedded Lithium Energy Cell Maintains
 Watch Function is Transparent to RAM
 Automatic Leap Year Compensation Valid
 Full 10% Operating Range
 Over 10 Years of Data Retention in the
 Lithium Energy Source is Electrically
 DIP Module Only
 Standard 28-Pin JEDEC Pinout
 PowerCap Module Board Only
 Underwriters Laboratories (UL) Recognized
www.maxim-ic.com
Hundredths of Seconds, Minutes, Hours,
Days, Date of the Month, Months, and Years
Volatile Static RAM or EEPROM
Calendar Operation and Retains RAM Data
Operation
Up to 2100
Absence of Power
Disconnected to Retain Freshness Until
Power is Applied for the First Time
– Surface Mountable Package for Direct
– Replaceable Battery (PowerCap)
– Pin-for-Pin Compatible with DS1248P
Connection to PowerCap Containing
Battery and Crystal
and DS1251P
256K NV SRAM with Phantom Clock
1 of 20
PIN CONFIGURATIONS
TOP VIEW
GND
N.C.
N.C.
N.C.
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
RST
V
WE
OE
CE
CC
A14/RST
(Uses DS9034PCX+ PowerCap)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
PowerCap Module
X1
EDIP Module
DS1244/DS1244P
1
2
3
4
5
6
7
8
9
10
11
12
13
14
(740 mils)
DS1244P
GND V
DS1244
BAT
28
27
26
25
24
23
22
21
20
19
18
17
16
15
X2
V
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
29
34
33
32
31
30
28
27
26
25
24
23
22
21
20
19
18
CC
N.C.
N.C.
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0

Related parts for DS1244

DS1244 Summary of contents

Page 1

... A11 A10 DQ7 11 18 DQ6 12 17 DQ5 13 16 DQ4 14 15 DQ3 EDIP Module (740 mils) N.C. 34 DS1244P N. A14 31 A13 30 A12 A11 29 A10 GND BAT 19 A1 ...

Page 2

... TEMP RANGE DS1244W-120+ 0°C to +70°C DS1244W-120IND+ -40°C to +85°C DS1244WP-120+ 0°C to +70°C DS1244WP-120IND+ -40°C to +85°C DS1244Y-70+ 0°C to +70°C DS1244YP-70+ 0°C to +70°C +Denotes a lead(Pb)-free/RoHS-compliant device. *DS9034PCX+ or DS9034I-PCX+ (PowerCap) required. (Must be ordered separately.) VOLTAGE PIN-PACKAGE (V) 28 EDIP (0.740a) 3 ...

Page 3

PIN DESCRIPTION PIN NAME EDIP PowerCap 1 1 A14/RST 1 32 A14 2 30 A12 A10 23 29 A11 ...

Page 4

... OE RAM WRITE MODE The DS1244 is in the write mode whenever the WE and CE signals are in the active (low) state after address inputs are stable. The latter occurring falling edge will determine the start of the write cycle. The write cycle is terminated by the earlier rising edge All address inputs must be kept valid throughout the write cycle ...

Page 5

DATA RETENTION MODE The 5V device is fully accessible and data can be written or read only when V However, when V is below the power fail point internal clock registers and SRAM are blocked from any access. ...

Page 6

PHANTOM CLOCK REGISTER INFORMATION The phantom clock information is contained in eight registers of 8 bits, each of which is sequentially accessed 1 bit at a time after the 64-bit pattern recognition sequence has been completed. When updating the phantom ...

Page 7

Figure 2. PHANTOM CLOCK REGISTER DEFINITION 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 ...

Page 8

... The DS1244 has a lithium power source that is designed to provide energy for clock activity and clock and RAM data retention when the V is sufficient to power the DS1244 continuously for the life of the equipment in which it is installed. For specification purposes, the life expectancy is 10 years at +25°C with the internal clock oscillator running in the absence of V power ...

Page 9

... Soldering Temperature (reflow, PowerCap) …………………………………………………… This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time can affect reliability. ...

Page 10

DC ELECTRICAL CHARACTERISTICS P ARAMETER 1 B Input Leakage Current I/O Leakage Current CE ≥ V ≤ Output Current at 2.4V Output Current at 0.4V Standby Current CE = 2.2V Standby Current 0.5V ...

Page 11

PHANTOM CLOCK AC ELECTRICAL CHARACTERISTICS P ARAMETER Read Cycle Time Access Time CE Access Time OE to Output Low Output Low Output High Output High-Z OE Read Recovery Write Cycle Time ...

Page 12

... CE to Output Low Output High Output High-Z OE Read Recovery Write Cycle Time Write Pulse Width Write Recovery Data Setup Time Data Hold Time Pulse Width CE Pulse Width RESET DS1244W-120 SYMBOL MIN t 120 RC t ACC COE t OD ...

Page 13

POWER-DOWN/POWER-UP TIMING P ARAMETER before Power-Down Slew from PF(MAX PF(MIN Slew from PF(MAX ...

Page 14

MEMORY READ CYCLE (Note 1) MEMORY WRITE CYCLE 1 (Notes 2, 6, and ...

Page 15

MEMORY WRITE CYCLE 2 (Notes 2 and 8) RESET FOR PHANTOM CLOCK READ CYCLE TO PHANTOM CLOCK ...

Page 16

WRITE CYCLE TO PHANTOM CLOCK ...

Page 17

POWER-DOWN/POWER-UP CONDITION, 5V POWER-DOWN/POWER-UP CONDITION, 3. ...

Page 18

... In addition, for the PowerCap: 1) Maxim recommends that PowerCap module bases experience one pass through solder reflow oriented with the label side up (“live-bug”). 2) Hand soldering and touch-up: Do not touch or apply the soldering iron to leads for more than three seconds. – ...

Page 19

... PACKAGE INFORMATION For the latest package outline information and land patterns (footprints www.maxim-ic.com/packages. Note that a “+”, “#”, or “-“ in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. ...

Page 20

... © 2011 Maxim Integrated Products DESCRIPTION Maxim is a registered trademark of Maxim Integrated Products, Inc. DS1244/DS1244P PAGES CHANGED ...

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