M41T315W-65MH6TR ST Microelectronics, M41T315W-65MH6TR Datasheet - Page 4

• Manufacturer Part Number: M41T315W-65MH6TR
• Description: Serial Access Phantom RTC Supervisor
• Manufacturer: ST Microelectronics

M41T315Y*, M41T315V, M41T315W
SUMMARY DESCRIPTION
The M41T315Y/V/W RTC Supervisor is a combi-
nation of a CMOS TIMEKEEPER
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 static RAM by switching on and
invoking write protection to prevent data corrup-
tion in the memory 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:
The nonvolatile supervisor 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.
Figure 3. Logic Diagram
4/24
–
–
RST
XO
a 12-hour mode with an AM/PM indicator;
or
a 24-hour mode
CEI
XI
WE
OE
D
(1)
(1)
V BAT
V CCI
M41T315W
M41T315Y
M41T315V
(1)
V CCO
V SS
®
and a nonvola-
CEO
Q
AI03902
The M41T315Y/V/W is supplied in a 28-lead SOIC
SNAPHAT
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 battery/crystal package to
be mounted on top of the SOIC package after the
completion of the surface mount process.
Insertion of the SNAPHAT housing after reflow
prevents potential battery and crystal damage due
to the high temperatures required for device sur-
face-mounting. The SNAPHAT housing is also
keyed to prevent reverse insertion.
The 28-pin SOIC 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
17., page
Caution: Do not place the SNAPHAT battery/crys-
tal top in conductive foam, as this will drain the lith-
ium button-cell battery.
Note: 1. For 16-pin SOIC only
Table 1. Signal Names
XI-XO
V
V
V
CEO
RST
V
CEI
WE
OE
NC
DU
CCO
BAT
CCI
Q
D
SS
is
22).
®
package (which integrates both crys-
“M4TXX-BR12SH”
32.768 kHz Crystal Connection
Data Input
Data Output
Reset Input
Chip Enable Output
Chip Enable Input
Battery Input
Output Enable Input
WRITE Enable Input
Switched Supply Voltage Output
Supply Voltage Input
Ground
Not Connected Internally
Don’t Use
(see
Table