Real time clock keeps track of hundredths of seconds,
minutes, hours, days, date of the month, months, and
years
minutes, hours, days, date of the month, months, and
years
? 32K x 8 NV SRAM directly replaces volatile static
RAM or EEPROM
RAM or EEPROM
? Embedded lithium energy cell maintains calendar op-
eration and retains RAM data
eration and retains RAM data
? Watch function is transparent to RAM operation
? Month and year determine the number of days in each
month; volid up to 1200
month; volid up to 1200
? Standard 28?pin JEDEC pinout
? Full 10% operating range
? Operating temperature range 0
? C to 70
?C
? Accuracy is better than
1 minute/month @ 25
?Over 10 years of data retention in the absence of
power
power
Reset
DESCRIPTION
The DS1244Y 256K NV SRAM with Phantom Clock is a
fully static nonvolatile RAM (organized as 32,768 words
by 8 bits) with a built?in real time clock. The DS1244Y
has a self?contained lithium energy source and control
circuitry which constantly monitors V
fully static nonvolatile RAM (organized as 32,768 words
by 8 bits) with a built?in real time clock. The DS1244Y
has a self?contained lithium energy source and control
circuitry which constantly monitors V
CC
for an out?of?
tolerance condition. When such a condition occurs, the
lithium energy source is automatically switched on and
write protection is unconditionally enabled to prevent
garbled data in both the memory and real time clock.
lithium energy source is automatically switched on and
write protection is unconditionally enabled to prevent
garbled data in both the memory and real time clock.