Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsIntegrated Circuits (ICs)Timer IC t- real time clock Phantom clock EDIP 28

1 of 20

FEATURES

 Real-Time Clock (RTC) Keeps Track of

Hundredths of Seconds, Minutes, Hours,

Days, Date of the Month, Months, and Years

 32K 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

 Full 10% Operating Range

 Over 10 Years of Data Retention in the

Absence of Power

 Lithium Energy Source is Electrically

Disconnected to Retain Freshness Until

Power is Applied for the First Time

 DIP Module Only

 Standard 28-Pin JEDEC Pinout

 PowerCap Module Board Only

– Surface Mountable Package for Direct

Connection to PowerCap Containing

Battery and Crystal

– Replaceable Battery (PowerCap)

– Pin-for-Pin Compatible with DS1248P

and DS1251P

 Underwriters Laboratories (UL) Recognized

PIN CONFIGURATIONS

EDIP Module

(740 mils)

A13

A11

A10

DQ7

DQ6

DQ5

DQ3

DQ4

A14/RST

A12

DQ0

DQ1

GND

DQ2

N.C.

DQ7

DQ6

DQ4

DQ3

DQ1

DQ0

N.C.

A12

A11

RST

N.C.

DQ5

DQ2

GND

A14

A13

A10

N.C.

GND

BAT

PowerCap Module

(Uses DS9034PCX+ PowerCap)

TOP VIEW

DS1244P

DS1244

DS1244/DS1244P

256K NV SRAM

with Phantom Clock

www.maxim-ic.com

19-6077; Rev 11/11

Summary of content (20 pages)

PAGE 1
9-6077; Rev 11/11 www.maxim-ic.
PAGE 2
DS1244/DS1244P TYPICAL OPERATING CIRCUIT ORDERING INFORMATION PART TEMP RANGE DS1244W-120+ DS1244W-120IND+ DS1244WP-120+ DS1244WP-120IND+ DS1244Y-70+ DS1244YP-70+ 0°C to +70°C -40°C to +85°C 0°C to +70°C -40°C to +85°C 0°C to +70°C 0°C to +70°C PIN-PACKAGE 28 EDIP (0.740a) 28 EDIP (0.740a) 34 PowerCap* 34 PowerCap* 28 EDIP (0.740a) 34 PowerCap* VOLTAGE (V) 3.3 3.3 3.3 3.3 5.0 5.0 +Denotes a lead(Pb)-free/RoHS-compliant device. *DS9034PCX+ or DS9034I-PCX+ (PowerCap) required.
PAGE 3
DS1244/DS1244P PIN DESCRIPTION EDIP PIN PowerCap NAME 1 1 A14/RST 1 2 3 4 5 6 7 8 9 10 21 23 24 25 26 11 12 13 15 16 17 18 19 20 22 27 32 30 25 24 23 22 21 20 19 18 28 29 27 26 31 16 15 14 13 12 11 10 9 8 7 6 2, 3, 4, 33, 34 5 17 A14 A12 A7 A6 A5 A4 A3 A2 A1 A0 A10 A11 A9 A8 A13 DQ0 DQ1 DQ2 DQ3 DQ4 DQ5 DQ6 DQ7 CE OE WE — 28 14 FUNCTION Address Input/Active-Low Reset Input. This pin has an internal pullup resistor connected to VCC. A14 address on the EDIP package.
PAGE 4
DS1244/DS1244P 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. The DS1244 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition.
PAGE 5
DS1244/DS1244P DATA RETENTION MODE The 5V device is fully accessible and data can be written or read only when VCC is greater than VPF. However, when VCC is below the power fail point, VPF (point at which write protection occurs), the internal clock registers and SRAM are blocked from any access. When VCC falls below the battery switch point, VSO (battery supply level), device power is switched from the VCC pin to the backup battery.
PAGE 6
DS1244/DS1244P 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 clock registers, each register must be handled in groups of 8 bits. Writing and reading individual bits within a register could produce erroneous results. These read/write registers are defined in Figure 2.
PAGE 7
DS1244/DS1244P 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 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).
PAGE 8
DS1244/DS1244P BATTERY LONGEVITY The DS1244 has a lithium power source that is designed to provide energy for clock activity and clock and RAM data retention when the VCC supply is not present. The capability of this internal power supply 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 VCC power.
PAGE 9
DS1244/DS1244P ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground (5V product) ………………………..-0.3V to +6.0V (3.3V product) ……………………..-0.3V to +4.6V Storage Temperature Range EDIP ………………………………………………………….……………………-40ºC to +85ºC PowerCap …………………………………………………………………………-55ºC to +125ºC Lead Temperature (soldering, 10 seconds) ……………………………………………………… +260ºC Note: EDIP is wave or hand-soldered only.
PAGE 10
DS1244/DS1244P DC ELECTRICAL CHARACTERISTICS PARAMETER Input Leakage Current I/O Leakage Current CE ≥ VIH ≤ VCC Output Current at 2.4V Output Current at 0.4V Standby Current CE = 2.2V Standby Current CE = VCC - 0.5V Operating Current tCYC = 70ns Write Protection Voltage Battery Switchover Voltage 1B Over the operating range (3.3V) SYMBOL IIL MIN -1.0 IIO -1.0 IOH IOL ICCS1 -1.0 2.0 TYP ICCS2 ICC01 VPF VSO 2.80 MAX +1.0 UNITS µA +1.0 µA 5 7 mA mA mA 2.0 3.0 mA 50 2.97 mA V V 2.
PAGE 11
DS1244/DS1244P PHANTOM CLOCK AC ELECTRICAL CHARACTERISTICS PARAMETER Read Cycle Time CE Access Time OE Access Time CE to Output Low-Z OE to Output Low-Z CE to Output High-Z OE to Output High-Z Read Recovery Write Cycle Time Write Pulse Width Write Recovery Data Setup Time Data Hold Time CE Pulse Width RESET Pulse Width 12B SYMBOL tRC tCO tOE tCOE tOEE tOD tODO tRR tWC tWP tWR tDS tDH tCW tRST MIN 65 TYP 5 5 10 65 55 10 30 0 60 65 POWER-DOWN/POWER-UP TIMING PARAMETER CE at VIH before Power-Down VCC Sl
PAGE 12
DS1244/DS1244P MEMORY AC ELECTRICAL CHARACTERISTICS PARAMETER Over the operating range (3.
PAGE 13
DS1244/DS1244P POWER-DOWN/POWER-UP TIMING PARAMETER CE at VIH before Power-Down VCC Slew from VPF(MAX) to VPF(MIN)( CE at VIH) VCC Slew from VPF(MAX) to VPF(MIN)( CE at VIH) CE at VIH after Power-Up 16B Over the operating range (3.3V) SYMBOL tPD tF MIN 0 300 tR 0 tREC 1.5 TYP MAX UNITS µs µs NOTES µs 2.
PAGE 14
DS1244/DS1244P MEMORY READ CYCLE (Note 1) MEMORY WRITE CYCLE 1 (Notes 2, 6, and 7) 14 of 20
PAGE 15
DS1244/DS1244P MEMORY WRITE CYCLE 2 (Notes 2 and 8) RESET FOR PHANTOM CLOCK READ CYCLE TO PHANTOM CLOCK 15 of 20
PAGE 16
DS1244/DS1244P WRITE CYCLE TO PHANTOM CLOCK 16 of 20
PAGE 17
DS1244/DS1244P POWER-DOWN/POWER-UP CONDITION, 5V POWER-DOWN/POWER-UP CONDITION, 3.
PAGE 18
DS1244/DS1244P AC TEST CONDITIONS Output Load: 50pF + 1TTL Gate Input Pulse Levels: 0 to 3V Timing Measurement Reference Levels Input: 1.5V Output: 1.5V Input Pulse Rise and Fall Times: 5ns 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.
PAGE 19
DS1244/DS1244P PACKAGE INFORMATION For the latest package outline information and land patterns (footprints), go to 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. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.
PAGE 20
DS1244/DS1244P REVISION HISTORY REVISION DATE 11/11 DESCRIPTION Updated the Features, Ordering Information, and Absolute Maximum Ratings sections PAGES CHANGED 1, 2, 9 20 of 20 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.