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June 2004
M41T315Y*
M41T315V/W
Serial Access Phantom RTC Supervisor
* Contact Local Sales Office
FEATURES SUMMARY
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
PFD
= Power-fail Deselect Voltage)
M41T315Y: V
CC
= 4.5 to 5.5V
4.25V
V
PFD
4.50V
M41T315V: V
CC
= 3.0 to 3.6V
2.80V
V
PFD
2.97V
M41T315W: V
CC
= 2.7 to 3.3V
2.60V
V
PFD
2.70V
NO ADDRESS SPACE REQUIRED TO
COMMUNICATE WITH RTC
PROVIDES NONVOLATILE SUPERVISOR
FUNCTIONS FOR BATTERY BACKUP OF
SRAM
FULL 10% V
CC
OPERATING RANGE
INDUSTRIAL OPERATING TEMPERATURE
RANGE (40 to +85C)
ULTRA-LOW BATTERY SUPPLY CURRENT
OF 500nA (max)
OPTIONAL PACKAGING INCLUDES A 28-
LEAD SOIC and SNAPHAT
TOP (to be
ordered separately)
SNAPHAT PACKAGE PROVIDES DIRECT
CONNECTION FOR A SNAPHAT TOP,
WHICH CONTAINS THE BATTERY AND
CRYSTAL
Figure 1. 16-pin SOIC Package
Figure 2. 28-pin SOIC Package
16
1
SO16 (MQ)
28
1
SOH28 (MH)
SNAPHAT (SH)
Battery/Crystal
M41T315Y*, M41T315V, M41T315W
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TABLE OF CONTENTS
FEATURES SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 1. 16-pin SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 2. 28-pin SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 3. Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Table 1. Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 4. 16-pin SOIC Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 5. 28-pin SOIC Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 6. Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 7. M41T315Y/V/W to RAM/Clock Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 2. Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Non-volatile Supervisor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 8. READ Mode Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 9. WRITE Mode Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 3. AC Electrical Characteristics (M41T315Y) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 4. AC Electrical Characteristics (M41T315V/W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 10.Comparison Register Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Data Retention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
CLOCK OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Clock Register Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
AM-PM/12/24 Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Oscillator and Reset Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Zero Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 5. RTC Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 11.Reset Pulse Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 6. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 7. DC and AC Measurement Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 12.AC Testing Load Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 8. Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 9. DC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 10. Crystal Electrical Characteristics (Externally Supplied) . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 13.Power Down/Up Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 11. Power Down/Up Trip Points DC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
PACKAGE MECHANICAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
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M41T315Y*, M41T315V, M41T315W
Figure 14.SO16 16-lead Plastic Small Outline, Package Outline . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 12. SO16 16-lead Plastic Small Outline (150 mils body width), Package Mech. Data . . . . 18
Figure 15.SOH28 28-lead Plastic Small Outline, Package Outline . . . . . . . . . . . . . . . . . . . . . . . 19
Table 13. SOH28 28-lead Plastic Small Outline, Package Mechanical Data . . . . . . . . . . . . . . . . 19
Figure 16.SH 4-pin SNAPHAT Housing for 48mAh Battery and Crystal, Package Outline . . . . . 20
Table 14. SH 4-pin SNAPHAT Housing for 48mAh Battery and Crystal, Package Mech. Data . . 20
Figure 17.SH 4-pin SNAPHAT Housing for 120mAh Battery and Crystal, Package Outline . . . . 21
Table 15. SH 4-pin SNAPHAT Housing for 120mAh Battery and Crystal, Package Mech. Data . 21
PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 16. Ordering Information Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 17. SNAPHAT Battery Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 18. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
M41T315Y*, M41T315V, M41T315W
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SUMMARY DESCRIPTION
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 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:
a 12-hour mode with an AM/PM indicator;
or
a 24-hour mode
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.
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 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 is "M4TXX-BR12SH" (see
Table
17., page 22
).
Caution: Do not place the SNAPHAT battery/crys-
tal top in conductive foam, as this will drain the lith-
ium button-cell battery.
Figure 3. Logic Diagram
Note: 1. For 16-pin SOIC only
Table 1. Signal Names
AI03902
D
Q
VCCI
M41T315Y
M41T315V
M41T315W
OE
VSS
CEI
WE
CEO
RST
VCCO
VBAT
XI
XO
(1)
(1)
(1)
XI-XO
32.768 kHz Crystal Connection
D
Data Input
Q
Data Output
RST
Reset Input
CEO
Chip Enable Output
CEI
Chip Enable Input
V
BAT
Battery Input
OE
Output Enable Input
WE
WRITE Enable Input
V
CCO
Switched Supply Voltage Output
V
CCI
Supply Voltage Input
V
SS
Ground
NC
Not Connected Internally
DU
Don't Use
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M41T315Y*, M41T315V, M41T315W
Figure 4. 16-pin SOIC Connections
Note: 1. Should be tied to V
SS
if not used.
Figure 5. 28-pin SOIC Connections
Figure 6. Block Diagram
AI03909
8
2
3
4
5
6
7
10
16
15
14
13
12
11
1
VBAT(1)
WE
VSS
RST
DU
OE
NC
VSS
XO
XI
VCCI
M41T315Y
D
Q
CEI
CEO
9
VCCO
M41T315W
M41T315V
AI03910
8
2
3
4
5
6
7
9
10
11
12
13
14
22
21
20
19
18
17
16
15
28
27
26
25
24
23
1
NC
VSS
VSS
NC
NC
WE
VCCI
M41T315Y
NC
NC
NC
NC
NC
Q
D
NC
NC
CEI
CEO
NC
OE
NC
DU
NC
RST
NC
NC
VCCO
NC
M41T315V
M41T315W
AI03636B
32,768 Hz
CRYSTAL
CEI
OE
WE
RST
CEO
CLOCK/CALENDAR LOGIC
TIMEKEEPER REGISTER
COMPARISON REGISTER
CONTROL
LOGIC
ACCESS
ENABLE
SEQUENCE
DETECTOR
I/O
BUFFERS
POWER-FAIL
DETECT
LOGIC
D
Q
VCCI
INTERNAL VCC
VCCO
READ
WRITE
POWER-FAIL
UPDATE
DATA
VBAT
XO
XI
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