DS1244W-120IND Maxim Integrated Products, DS1244W-120IND Datasheet - Page 8

• Manufacturer Part Number: DS1244W-120IND
• Description: IC NVSRAM 256KBIT 120NS 28DIP
• Manufacturer: Maxim Integrated Products

Specifications of DS1244W-120IND

• Format - Memory: RAM
• Memory Type: NVSRAM (Non-Volatile SRAM)
• Memory Size: 256K (32K x 8)
• Speed: 120ns
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-DIP Module (600 mil), 28-EDIP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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 V
supply is not present. The capability of this internal power supply
CC
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. Each DS1244 is shipped from Dallas Semiconductor with its lithium energy
CC
source disconnected, guaranteeing full energy capacity. When V
is first applied at a level greater than
CC
V
, the lithium energy source is enabled for battery-backup operation. Actual life expectancy of the
PF
DS1244 will be much longer than 10 years since no lithium battery energy is consumed when V
is
CC
present.
See “Conditions of Acceptability” at www.maxim-ic.com/TechSupport/QA/ntrl.htm.
CLOCK ACCURACY (DIP MODULE)
The DS1244 is guaranteed to keep time accuracy to within 1 minute per month at +25C. The clock is
calibrated at the factory by Dallas Semiconductor using special calibration nonvolatile tuning elements
and does not require additional calibration. For this reason, methods of field clock calibration are not
available and not necessary.
CLOCK ACCURACY (POWERCAP MODULE)
The DS1244P and DS9034PCX are each individually tested for accuracy. Once mounted together, the
module will typically keep time accuracy to within 1.53 minutes per month (35ppm) at +25C.
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