M41T315Y*

` 3.0V, 3.3V, OR 5V OPERATING VOLTAGE
` REAL TIME CLOCK KEEPS TRACK OF TENTHS/HUNDREDTHS OF SECONDS, SECONDS, MINUTES, HOURS, DAYS, DATE OF THE MONTH, MONTHS, and YEARS
` AUTOMATIC LEAP YEAR CORRECTION VALID UP TO 2100
` AUTOMATIC SWITCH-OVER and DESELECT CIRCUITRY
` CHOICE OF POWER-FAIL DESELECT VOLTAGES:
(V<sub>PFD</sub> = Power-fail Deselect Voltage)
M41T315Y: V<sub>CC</sub> = 4.5 to 5.5V
4.25V V<sub>PFD</sub> 4.50V
M41T315V: V<sub>CC</sub> = 3.0 to 3.6V
2.80V V<sub>PFD</sub> 2.97V
M41T315W: V<sub>CC</sub> = 2.7 to 3.3V
2.60V V<sub>PFD</sub> 2.70V
` NO ADDRESS SPACE REQUIRED TO COMMUNICATE WITH RTC
` PROVIDES NONVOLATILE SUPERVISOR FUNCTIONS FOR BATTERY BACKUP OF SRAM
` FULL ±10% VCC OPERATING RANGE
` INDUSTRIAL OPERATING TEMPERATURE RANGE (40 to +85°C)
` ULTRA-LOW BATTERY SUPPLY CURRENT OF 500 nA (max)
` OPTIONAL PACKAGING INCLUDES A 28-LEAD SOIC and SNAPHAT<sup>®</sup> TOP (to be ordered separately)
` SNAPHAT PACKAGE PROVIDES DIRECT CONNECTION FOR A SNAPHAT TOP, WHICH CONTAINS THE BATTERY and CRYSTAL

Note: 1. Reflow at peak temperature of 215°C to 225°C for < 60 seconds (total thermal budget not to exceed 180°C for between 90 to 120 seconds).

The M41T315Y/V/W RTC Supervisor is a combi-nation of a CMOS TIMEKEEPER® and a nonvola-tile memory supervisor. Power is constantly monitored by the memory supervisor. In the event of power instability or absence, an external battery maintains the timekeeping operation and provides power for a CMOS M41T315Y/V/W static RAM by switching on and invoking write protection to prevent data corrup-tion in the memory and RTC.

The clock M41T315Y/V/W 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 M41T315Y/V/W operates in one of two formats:
a 12-hour mode with an AM/PM indicator; or
a 24-hour mode

The nonvolatile supervisor M41T315Y/V/W supplies all the neces-sary support circuitry to convert a CMOS RAM to a nonvolatile memory. The M41T315Y/V/W can be interfaced with RAM without leaving gaps in memory.

The M41T315Y/V/W is supplied in a 28-lead SOIC SNAPHAT® package (which integrates both crys-tal and battery in a single SNAPHAT top) or a-16 pin SOIC. The 28-pin, 330mil SOIC provides sock-ets with gold plated contacts at both ends for direct connection to a separate SNAPHAT housing con-taining the battery and crystal. The unique design allows the SNAPHAT M41T315Y/V/W battery/crystal package to be mounted on top of the SOIC package of M41T315Y/V/W after the completion of the surface mount process.

Insertion of the SNAPHAT M41T315Y/V/W housing after reflow prevents potential battery and crystal damage due to the high temperatures required for device sur-face-mounting. The SNAPHAT M41T315Y/V/W housing is also keyed to prevent reverse insertion.

The 28-pin SOIC M41T315Y/V/W and battery/crystal packages are shipped separately in plastic anti-static tubes or in Tape & Reel form. For the 28-lead SOIC, the bat-tery/crystal package (e.g., SNAPHAT) part num-ber is "M4TXX-BR12SH"M41T315Y/V/W (see Table 17, page 20).

Caution: Do not place the SNAPHAT battery/crys-tal top in conductive foam, as this will drain the lith-ium button-cell battery.