Features: ` 3.3V ± 10%
` INTEGRATED ULTRA LOW POWER SRAM, REAL TIME CLOCK, POWER-FAIL CONTROL CIRCUIT, BATTERY AND CRYSTAL
` REAL TIME CLOCK KEEPS TRACK OF TENTHS/HUNDREDTHS OF SECONDS, SECONDS, MINUTES, HOURS, DAYS, DATE, MONTHS, and YEARS.
` CLOCK FUNCTION IS TRANSPARENT TO RAM OPERATION.
` PRECISION POWER MONITORING and POWER SWITCHING CIRCUITRY
` AUTOMATIC WRITE-PROTECTION WHEN
VCC IS OUT-OF-TOLERANCE
` POWER-FAIL DESELECT VOLTAGE:
VCC = 3.3V ± 10%; 2.8V VPFD 2.97V
` BATTERY LOW (BL)
` 10 YEARS of DATA RETENTION and CLOCK OPERATION IN THE ABSENCE OF POWER
` SNAPHAT HOUSING (BATTERY/CRYSTAL) IS REPLACEABLE
` 100ns ACCESS (READ = WRITE)
Specifications
| Symbol |
Parameter |
Value |
Unit |
| TA |
Operating Temperature |
0 to 70 |
|
| TSTG |
Storage Temperature (VCC, Oscillator Off) |
40 to 85 |
|
| TSLD |
Lead Solder Temperature for 10 seconds |
260 |
|
| VCC |
Supply Voltage (on any pin relative to Ground) |
0.3 to +4.6 |
V |
| VIO |
Input or Output Voltage |
0.3 to VCC + 0.3 |
V |
| IO |
Output Current |
20 |
mA |
| PD |
Power Dissipation |
1 |
W |
DescriptionThe M48T254V TIMEKEEPER® RAM is a 2Mbit x 8 non-volatile static RAM and real time clock orga-nized as 2,097,152 words by 8 bits. The special BGA package provides a fully integrated battery back-up memory and real time clock solution. In the event of power instability or absence, a self-contained battery maintains the timekeeping oper-ation and provides power for a CMOS static RAM.
Control circuitry of M48T254V monitors VCC and invokes write protection to prevent data corruption in the memo-ry and RTC.
The clock keeps track of tenths/hundredths of sec-onds, seconds, minutes, hours, day, date, month, and year information. The last day of the month is automatically adjusted for months with less than 31 days, including leap year correction.
The clock operates in one of two formats:
a 12-hour mode with an AM/PM indicator; or
a 24-hour mode
The M48T254V is a 168-ball PBGA module that in-tegrates the RTC, the battery, and SRAM in one package.
M48T254V Data Sheet
