STMicroelectronics M48T212Y-70MH6 5v/3.3v timekeeper controller supervisor Datasheet

M48T212Y
M48T212V
5.0V or 3.3V TIMEKEEPER® Supervisor
FEATURES SUMMARY
■
■
■
■
■
■
■
■
■
■
INTEGRATED REAL TIME CLOCK, POWERFAIL CONTROL CIRCUIT, BATTERY AND
CRYSTAL
CONVERTS LOW POWER SRAM INTO
NVRAMs
YEAR 2000 COMPLIANT (4-Digit Year)
BATTERY LOW FLAG
MICROPROCESSOR POWER-ON RESET
PROGRAMMABLE ALARM OUTPUT
ACTIVE IN THE BATTERY BACKED-UP
MODE
WATCHDOG TIMER
AUTOMATIC POWER-FAIL CHIP
DESELECT AND WRITE PROTECTION
CHOICE OF WRITE PROTECT VOLTAGES
(VPFD = Power-fail Deselect Voltage):
– M48T212Y: VCC = 4.5 to 5.5V
4.2V ≤ VPFD ≤ 4.5V
– M48T212V: VCC = 3.0 to 3.6V
2.7V ≤ VPFD ≤ 3.0V
PACKAGING INCLUDES A 44-LEAD SOIC
AND SNAPHAT® TOP (to be ordered
separately)
April 2004
Figure 1. 44-pin SOIC Package
SNAPHAT (SH)
Crystal/Battery
44
1
SOH44 (MH)
1/32
M48T212Y, M48T212V
TABLE OF CONTENTS
FEATURES SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 1. 44-pin SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 2.
Table 1.
Figure 3.
Figure 4.
Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SOIC Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hardware Hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.......
.......
.......
.......
......
......
......
......
......
......
......
......
.....5
.....5
.....6
.....7
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Address Decoding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 2. Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 3. Truth Table for SRAM Bank Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 5. Chip Enable Control and Bank Select Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 4. Chip Enable Control and Bank Select Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
READ Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 6. READ Cycle Timing: RTC Control Signal Waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 5. READ Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
WRITE Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 7. WRITE Cycle Timing: RTC Control Signal Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 6. WRITE Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Data Retention Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
CLOCK OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
TIMEKEEPER® Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Reading the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Setting the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Stopping and Starting the Oscillator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 7. TIMEKEEPER® Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Setting the Alarm Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 8. Alarm Interrupt Reset Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 8. Alarm Repeat Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 9. Back-up Mode Alarm Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
VCC Switch Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Power-on Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 10.(RSTIN1 & RSTIN2) Timing Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 9. Reset AC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Calibrating the Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Battery Low Warning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Initial Power-on Defaults. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 10. Default Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 11.Crystal Accuracy Across Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2/32
M48T212Y, M48T212V
Figure 12.Calibration Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
VCC Noise And Negative Going Transients. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 13.Supply Voltage Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 11. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 12. DC and AC Measurement Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 14.AC Testing Load Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 13. Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Table 14. DC Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figure 15.Power Down/Up Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 15. Power Down/Up Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
PACKAGE MECHANICAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 16.SOH44 – 44-lead Plastic Small Outline, SNAPHAT, Package Outline . . . . . . . . . . . . . . 27
Table 16. SOH44 – 44-lead Plastic Small Outline, SNAPHAT, Package Mechanical Data . . . . . . 27
Figure 17.SH – 4-pin SNAPHAT Housing for 48 mAh Battery & Crystal, Package Outline . . . . . . 28
Table 17. SH – 4-pin SNAPHAT Housing for 48 mAh Battery & Crystal, Package Mech. Data . . . 28
Figure 18.SH – 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Outline . . . . . . 29
Table 18. SH – 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Mech. Data. . . 29
PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 19. Ordering Information Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Table 20. SNAPHAT® Battery Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
REVISION HISTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 21. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3/32
M48T212Y, M48T212V
DESCRIPTION
The M48T212Y/V are self-contained devices that
include a real time clock (RTC), programmable
alarms, a watchdog timer, and two external chip
enable outputs which provide control of up to four
(two in parallel) external low-power static RAMs.
Access to all TIMEKEEPER® functions and the
external RAM is the same as conventional bytewide SRAM. The 16 TIMEKEEPER Registers offer
Century, Year, Month, Date, Day, Hour, Minute,
Second, Calibration, Alarm, Watchdog, and Flags.
Externally attached static RAMs are controlled by
the M48T212Y/V via the E1CON and E2CON signals (see Table 3., page 8).
The 44-pin, 330mil SOIC provides sockets with
gold plated contacts at both ends for direct connection to a separate SNAPHAT® housing containing the battery and crystal. The unique design
allows the SNAPHAT battery package to be
4/32
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 surface-mounting. The SNAPHAT housing is keyed
to prevent reverse insertion.
The SOIC and battery/crystal packages are
shipped separately in plastic anti-static tubes or in
Tape & Reel form. For the-44 lead SOIC, the battery/crystal package (e.g., SNAPHAT) part number
is
“M4TXX-BR12SH”
(see
Table
20., page 30).
Caution: Do not place the SNAPHAT battery/crystal top in conductive foam, as this will drain the lithium button-cell battery.
M48T212Y, M48T212V
Figure 2. Logic Diagram
Table 1. Signal Names
A0-A3
DQ0-DQ7
VCC
VCCSW
4
Data Inputs/Outputs
RSTIN1
Reset 1 Input
RSTIN2
Reset 2 Input
RST
Reset Output (Open Drain)
WDI
Watchdog Input
8
A0-A3
DQ0-DQ7
A
E
IRQ/FT
RST
EX
W
Address Inputs
M48T212Y
M48T212V
G
Bank Select Input
E
Chip Enable Input
EX
External Chip Enable Input
E1CON
G
Output Enable Input
E2CON
W
WRITE Enable Input
WDI
RSTIN1
A
VOUT
RSTIN2
E1CON
RAM Chip Enable 1 Output
E2CON
RAM Chip Enable 2 Output
IRQ/FT
Int/Freq Test Output (Open Drain)
Vccsw
VCC Switch Output
VOUT
Supply Voltage Output
VCC
Supply Voltage
VSS
Ground
NC
Not Connected internally
VSS
AI03019
5/32
M48T212Y, M48T212V
Figure 3. SOIC Connections
RSTIN1
RSTIN2
RST
NC
NC
NC
NC
NC
A
NC
NC
NC
A3
A2
A1
A0
WDI
E2CON
DQ0
DQ1
DQ2
VSS
44
1
2
43
3
42
4
41
5
40
6
39
38
7
37
8
9
36
10
35
M48T212Y
11 M48T212V 34
12
33
13
32
14
31
15
30
16
29
17
28
18
27
19
26
20
25
21
24
22
23
AI03020
6/32
VCC
VOUT
VCCSW
IRQ/FT
EX
NC
NC
NC
NC
NC
G
W
NC
NC
E
E1CON
DQ7
DQ6
DQ5
DQ4
DQ3
NC
M48T212Y, M48T212V
Figure 4. Hardware Hookup
A0-A18
5V/3.3V
VCCSW
VCC
0.1µF
MOTOROLA
MTD20P06HDL
A0-A3
A0-Axx
1N5817(1)
VOUT
A
VCC
0.1µF
E
E2(3)
CMOS
SRAM
E
EX
W
E1CON
Note 2
G
E2CON
WDI
RSTIN1
RSTIN2
DQ0-DQ7
A0-Axx
RST
IRQ/FT
VSS
VCC
(3)
E2
CMOS
SRAM
E
M48T212Y/V
AI03046
Note: 1. See description in Power Supply Decoupling and Undershoot Protection.
2. Traces connecting E1CON and E2CON to external SRAM should be as short as possible.
3. If the second chip enable pin (E2) is unused, it should be tied to VOUT.
7/32
M48T212Y, M48T212V
OPERATION
Automatic backup and write protection for an external SRAM is provided through VOUT, E1CON
and E2CON pins. (Users are urged to insure that
voltage specifications, for both the SUPERVISOR
chip and external SRAM chosen, are similar). The
SNAPHAT® containing the lithium energy source
used to permanently power the real time clock is
also used to retain RAM data in the absence of
VCC power through the VOUT pin.
The chip enable outputs to RAM (E1CON and
E2CON) are controlled during power transients to
prevent data corruption. The date is automatically
adjusted for months with less than 31 days and
corrects for leap years (valid until 2100). The internal watchdog timer provides programmable alarm
windows.
The nine clock bytes (Fh-9h and 1h) are not the
actual clock counters, they are memory locations
consisting of BiPORT™ READ/WRITE memory
cells within the static RAM array. Clock circuitry
updates the clock bytes with current information
once per second. The information can be accessed by the user in the same manner as any other location in the static memory array.
Byte 8h is the clock control register. This byte controls user access to the clock information and also
stores the clock calibration setting. Byte 7h contains the watchdog timer setting. The watchdog
timer can generate either a reset or an interrupt,
depending on the state of the Watchdog Steering
Bit (WDS). Bytes 6h-2h include bits that, when
programmed, provide for clock alarm functionality.
Alarms are activated when the register content
matches the month, date, hours, minutes, and
seconds of the clock registers. Byte 1h contains
century information. Byte 0h contains additional
flag information pertaining to the watchdog timer,
alarm and battery status.
The M48T212Y/V also has its own Power-Fail Detect circuit. This control circuitry constantly monitors the supply voltage for an out of tolerance
condition. When VCC is out of tolerance, the circuit
write protects the TIMEKEEPER® register data
and external SRAM, providing data security in the
midst of unpredictable system operation. As VCC
falls below VSO, the control circuitry automatically
switches to the battery, maintaining data and clock
operation until valid power is restored.
Address Decoding
The M48T212Y/V accommodates 4 address lines
(A3-A0) which allow access to the sixteen bytes of
the TIMEKEEPER clock registers. All TIMEKEEPER registers reside in the SUPERVISOR chip itself. All TIMEKEEPER registers are accessed by
enabling E (Chip Enable).
Table 2. Operating Modes
Mode
VCC
Deselect
WRITE
READ
4.5V to 5.5V
or
3.0V to 3.6V
READ
Deselect
Deselect
VSO to VPFD (min)(1)
≤ VSO
(1)
E
G
VIH
W
DQ7-DQ0
Power
VIL
X
X
High-Z
Standby
X
VIL
DIN
Active
VIL
VIL
VIH
DOUT
Active
VIL
VIH
VIH
High-Z
Active
X
X
X
High-Z
CMOS Standby
X
X
X
High-Z
Battery Back-Up
EX
A
E1CON
E2CON
Power
Low
Low
Low
High
Active
Note: X = VIH or VIL; VSO = Battery Back-up Switchover Voltage
1. See Table 14., page 25 for details.
Table 3. Truth Table for SRAM Bank Select
Mode
VCC
Select
4.5V to 5.5V
or
3.0V to 3.6V
Deselect
Low
High
High
Low
Active
High
X
High
High
Standby
Deselect
VSO to VPFD (min)(1)
X
X
High
High
CMOS Standby
Deselect
≤ VSO(1)
X
X
High
High
Battery Back-Up
Note: X = VIH or VIL; VSO = Battery Back-up Switchover Voltage
1. See Table 14., page 25 for details.
8/32
M48T212Y, M48T212V
Figure 5. Chip Enable Control and Bank Select Timing
EX
tEXPD
tAPD
A
tEXPD
E1CON
E2CON
AI02639
Table 4. Chip Enable Control and Bank Select Characteristics
Symbol
M48T212Y
M48T212V
–70
–85
Parameter
Min
Max
Min
Unit
Max
tEXPD
EX to E1CON or E2CON (Low or High)
10
15
ns
tAPD
A to E1CON or E2CON (Low or High)
10
15
ns
9/32
M48T212Y, M48T212V
READ Mode
The M48T212Y/V executes a READ cycle whenever W (WRITE Enable) is high and E (Chip Enable) is low. The unique address specified by the
address inputs (A3-A0) defines which one of the
on-chip TIMEKEEPER® registers is to be accessed. When the address presented to the
M48T212Y/V is in the range of 0h-Fh, one of the
on-board TIMEKEEPER registers is accessed and
valid data will be available to the eight data output
drivers within tAVQV after the address input signal
is stable, providing that the E and G access times
are also satisfied.If they are not, then data access
must be measured from the latter occurring signal
(E or G) and the limiting parameter is either tELQV
for E or tGLQV for G rather than the address access
time.
When EX input is low, an external SRAM location
will be selected.
Note: Care should be taken to avoid taking both E
and EX low simultaneously to avoid bus contention.
Figure 6. READ Cycle Timing: RTC Control Signal Waveforms
READ
tAVAV
READ
WRITE
tAVAV
tAVAV
ADDRESS
tELQV
tAVQV
tAVWL
tWHAX
E
tELQX
tGLQV
G
tWLWH
W
tGLQX
tAXQX
tGHQZ
DATA OUT
VALID
DATA OUT
VALID
DQ7-DQ0
DATA IN
VALID
AI02640
Note: EX is assumed High.
Table 5. READ Mode AC Characteristics
Symbol
M48T212Y
M48T212V
–70
–85
(1)
Parameter
Min
Max
Min
Unit
Max
tAVAV
Read Cycle Time
tAVQV
Address Valid to Output Valid
70
85
ns
tELQV
Chip Enable Low to Output Valid
70
85
ns
tGLQV
Output Enable Low to Output Valid
25
35
ns
70
85
ns
tELQX(2)
Chip Enable Low to Output Transition
5
5
ns
tGLQX(2)
Output Enable Low to Output Transition
0
0
ns
tEHQZ(2)
Chip Enable High to Output Hi-Z
20
25
ns
tGHQZ(2)
Output Enable High to Output Hi-Z
20
25
ns
tAXQX
Address Transition to Output Transition
5
5
ns
Note: 1. Valid for Ambient Operating Temperature: TA = 0 to 70°C or –40 to 85°C; VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
2. CL = 5pF.
10/32
M48T212Y, M48T212V
WRITE Mode
The M48T212Y/V is in the WRITE Mode whenever
W (WRITE Enable) and E (Chip Enable) are in a
low state after the address inputs are stable. The
start of a WRITE is referenced from the latter occurring falling edge of W or E. A WRITE is terminated by the earlier rising edge of W or E. The
addresses must be held valid throughout the cycle. E or W must return high for a minimum of tEHAX from Chip Enable or tWHAX from WRITE
Enable prior to the initiation of another READ or
WRITE cycle. Data-in must be valid tDVWH prior to
the end of WRITE and remain valid for tWHDX afterward.
G should be kept high during WRITE cycles to
avoid bus contention; although, if the output bus
has been activated by a low on E and G a low on
W will disable the outputs tWLQZ after W falls.
When E is low during the WRITE, one of the onboard TIMEKEEPER® registers will be selected
and data will be written into the device. When EX
is low (and E is high) an external SRAM location is
selected.
Note: Care should be taken to avoid taking both E
and EX low simultaneously to avoid bus contention.
Figure 7. WRITE Cycle Timing: RTC Control Signal Waveforms
WRITE
WRITE
READ
tAVAV
tAVAV
tAVAV
ADDRESS
tAVEH
tAVEL
tELEH
tAVWH
tEHAX
tWHAX
tAVQV
E
tGLQV
G
tEHDX
tAVWL
tWLWH
tWHQX
tWLQZ
W
tEHQZ
DQ0-DQ7
DATA OUT
VALID
tDVEH
DATA IN
VALID
tDVWH
tWHDX
DATA IN
VALID
DATA OUT
VALID
AI02641
Note: EX is assumed High.
11/32
M48T212Y, M48T212V
Table 6. WRITE Mode AC Characteristics
Symbol
M48T212Y
M48T212V
–70
–85
(1)
Parameter
Min
Max
Min
Unit
Max
tAVAV
Write Cycle Time
70
85
ns
tAVWL
Address Valid to Write Enable Low
0
0
ns
tAVEL
Address Valid to Chip Enable Low
0
0
ns
tWLWH
Write Enable Pulse Width
45
55
ns
tELEH
Chip Enable Low to Chip Enable High
50
60
ns
tWHAX
Write Enable High to Address Transition
0
0
ns
tEHAX
Chip Enable High to Address Transition
0
0
ns
tDVWH
Input Valid to Write Enable High
25
30
ns
tDVEH
Input Valid to Chip Enable High
25
30
ns
tWHDX
Write Enable High to Input Transition
0
0
ns
tEHDX
Chip Enable High to Input Transition
0
0
ns
tWLQZ(2,3)
Write Enable Low to Output High-Z
tAVWH
Address Valid to Write Enable High
55
65
ns
tAVEH
Address Valid to Chip Enable High
55
65
ns
Write Enable High to Output Transition
5
5
ns
tWHQX(2,3)
20
25
ns
Note: 1. Valid for Ambient Operating Temperature: TA = 0 to 70°C or –40 to 85°C; VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
2. CL = 5pF
3. If E goes low simultaneously with W going low, the outputs remain in the high impedance state.
12/32
M48T212Y, M48T212V
Data Retention Mode
With valid VCC applied, the M48T212Y/V can be
accessed as described above with READ or
WRITE cycles. Should the supply voltage decay,
the M48T212Y/V will automatically deselect, write
protecting itself (and any external SRAM) when
VCC falls between VPFD (max) and VPFD (min).
This is accomplished by internally inhibiting access to the clock registers via the E signal. At this
time, the Reset pin (RST) is driven active and will
remain active until VCC returns to nominal levels.
External RAM access is inhibited in a similar manner by forcing E1CON and E2CON to a high level.
This level is within 0.2 volts of the VBAT. E1CON
and E2CON will remain at this level as long as VCC
remains at an out-of-tolerance condition.
When VCC falls below battery back-up switchover
voltage (VSO), power input is switched from the
VCC pin to the SNAPHAT® battery and the clock
registers and external SRAM are maintained from
the attached battery supply. All outputs become
high impedance. The VOUT pin is capable of supplying 100µA of current to the attached memory
with less than 0.3V drop under this condition. On
power up, when VCC returns to a nominal value,
write protection continues for 200ms (max) by inhibiting E1CON or E2CON.
The RST signal also remains active during this
time (see Figure 15., page 26).
Note: Most low power SRAMs on the market today can be used with the M48T212Y/V TIMEKEEPER® SUPERVISOR. There are, however
some criteria which should be used in making the
final choice of an SRAM to use. The SRAM must
be designed in a way where the chip enable input
disables all other inputs to the SRAM. This allows
inputs to the M48T212Y/V and SRAMs to be
“Don't care” once VCC falls below VPFD(min). The
SRAM should also guarantee data retention down
to VCC = 2.0V. The chip enable access time must
be sufficient to meet the system needs with the
chip enable output propagation delays included.
If the SRAM includes a second chip enable pin
(E2), this pin should be tied to VOUT.
If data retention lifetime is a critical parameter for
the system, it is important to review the data retention current specifications for the particular
SRAMs being evaluated. Most SRAMs specify a
data retention current at 3.0V. Manufacturers generally specify a typical condition for room temperature along with a worst case condition (generally
at elevated temperatures). The system level requirements will determine the choice of which value to use.
The data retention current value of the SRAMs can
then be added to the IBAT value of the M48T212Y/
V to determine the total current requirements for
data retention. The available battery capacity for
the SNAPHAT® of your choice can then be divided
by this current to determine the amount of data retention available (see Table 20., page 30).
For a further more detailed review of lifetime calculations, please see Application Note AN1012.
13/32
M48T212Y, M48T212V
CLOCK OPERATION
TIMEKEEPER ® Registers
The M48T212Y/V offers 16 internal registers
which contain TIMEKEEPER®, Alarm, Watchdog,
Flag, and Control data. These registers are memory locations which contain external (user accessible) and internal copies of the data (usually
referred to as BiPORT™ TIMEKEEPER cells).
The external copies are independent of internal
functions except that they are updated periodically
by the simultaneous transfer of the incremented
internal copy. TIMEKEEPER and Alarm Registers
store data in BCD. Control, Watchdog and Flags
Registers store data in Binary Format.
Reading the Clock
Updates to the TIMEKEEPER registers should be
halted before clock data is read to prevent reading
data in transition. The BiPORT TIMEKEEPER
cells in the RAM array are only data registers and
not the actual clock counters, so updating the registers can be halted without disturbing the clock itself.
Updating is halted when a '1' is written to the
READ Bit, D6 in the Control Register (8h). As long
as a '1' remains in that position, updating is halted.
After a halt is issued, the registers reflect the
count; that is, the day, date, and time that were
current at the moment the halt command was issued.
All of the TIMEKEEPER registers are updated simultaneously. A halt will not interrupt an update in
progress. Updating occurs 1 second after the
READ Bit is reset to a '0.'
14/32
Setting the Clock
Bit D7 of the Control Register (8h) is the WRITE
Bit. Setting the WRITE Bit to a '1,' like the READ
Bit, halts updates to the TIMEKEEPER registers.
The user can then load them with the correct day,
date, and time data in 24 hour BCD format (see
Table 7., page 15).
Resetting the WRITE Bit to a '0' then transfers the
values of all time registers (Fh-9h, 1h) to the actual
TIMEKEEPER counters and allows normal operation to resume. After the WRITE Bit is reset, the
next clock update will occur one second later.
Note: Upon power-up following a power failure,
the READ Bit will automatically be set to a '1.' This
will prevent the clock from updating the TIMEKEEPER registers, and will allow the user to read
the exact time of the power-down event.
Resetting the READ Bit to a '0' will allow the clock
to update these registers with the current time.
The WRITE Bit will be reset to a '0' upon power-up.
Stopping and Starting the Oscillator
The oscillator may be stopped at any time. If the
device is going to spend a significant amount of
time on the shelf, the oscillator can be turned off to
minimize current drain on the battery. The STOP
Bit is located at Bit D7 within the Seconds Register
(9h). Setting it to a '1' stops the oscillator. When reset to a '0,' the M48T212Y/V oscillator starts within
one second.
Note: It is not necessary to set the WRITE Bit
when setting or resetting the FREQUENCY TEST
Bit (FT) or the STOP Bit (ST).
M48T212Y, M48T212V
Table 7. TIMEKEEPER® Register Map
Address
D7
D6
Fh
D5
D4
D3
D2
10 Years
D0
Function/Range
BCD Format
Year
Year
00-99
Month
Month
01-12
Date: Day of Month
Date
01-31
Day
01-7
Hours (24 Hour Format)
Hours
00-23
Eh
0
0
Dh
0
0
Ch
0
FT
Bh
0
0
Ah
0
10 Minutes
Minutes
Min
00-59
9h
ST
10 Seconds
Seconds
Sec
00-59
8h
W
R
S
7h
WDS
BMB4
BMB3
BMB2
6h
AFE
0
ABE
Al 10M
5h
RPT4
RPT5
4h
RPT3
0
3h
RPT2
2h
RPT1
1h
0h
0
D1
10M
10 Date
0
0
0
10 Hours
Calibration
BMB1
BMB0
Control
RB1
RB0
Watchdog
Alarm Month
A Month
01-12
AI 10 Date
Alarm Date
A Date
01-31
AI 10 Hour
Alarm Hour
A Hour
00-23
Alarm 10 Minutes
Alarm Minutes
A Min
00-59
Alarm 10 Seconds
Alarm Seconds
A Sec
00-59
100 Year
Century
00-99
1000 Year
WDF
Day of Week
AF
Y
Keys: S = Sign Bit
FT = Frequency Test Bit
R = READ Bit
W = WRITE Bit
ST = Stop Bit
0 = Must be set to '0'
BL = Battery Low Flag (Read only)
BMB0-BMB4 = Watchdog Multiplier Bits
BL
Y
Y
Y
Y
Flag
AFE = Alarm Flag Enable Flag
RB0-RB1 = Watchdog Resolution Bits
WDS = Watchdog Steering Bit
ABE = Alarm in Battery Back-Up Mode Enable Bit
RPT1-RPT5 = Alarm Repeat Mode Bits
WDF = Watchdog Flag (Read only)
AF = Alarm Flag (Read only)
Y = '1' or '0'
15/32
M48T212Y, M48T212V
Setting the Alarm Clock
Address locations 6h-2h contain the alarm settings. The alarm can be configured to go off at a
prescribed time on a specific month, date, hour,
minute, or second or repeat every year, month,
day, hour, minute, or second. It can also be programmed to go off while the M48T212Y/V is in the
battery back-up to serve as a system wake-up call.
Bits RPT5-RPT1 put the alarm in the repeat mode
of operation. Table 8 shows the possible configurations. Codes not listed in the table default to the
once per second mode to quickly alert the user of
an incorrect alarm setting.
Note: User must transition address (or toggle chip
enable) to see Flag Bit change.
When the clock information matches the alarm
clock settings based on the match criteria defined
by RPT5-RPT1, the AF (Alarm Flag) is set.
If AFE (Alarm Flag Enable) is also set, the alarm
condition activates the IRQ/FT pin. To disable
alarm, write '0' to the Alarm Date registers and
RPT1-5. The IRQ/FT output is cleared by a READ
to the Flags Register as shown in Figure 8. A subsequent READ of the Flags Register is necessary
to see that the value of the Alarm Flag has been
reset to '0.'
The IRQ/FT pin can also be activated in the battery back-up mode. The IRQ/FT will go low if an
alarm occurs and both ABE (Alarm in Battery
Back-up Mode Enable) and AFE are set. The ABE
and AFE Bits are reset during power-up, therefore
an alarm generated during power-up will only set
AF. The user can read the Flag Register at system
boot-up to determine if an alarm was generated
while the M48T212Y/V was in the deselect mode
during power-up. Figure 9., page 17 illustrates the
back-up mode alarm timing.
Figure 8. Alarm Interrupt Reset Waveforms
ADDRESS 0h
1h
A0-A3
Fh
ACTIVE FLAG BIT
IRQ/FT
HIGH-Z
AI03021
Table 8. Alarm Repeat Modes
RPT5
RPT4
RPT3
RPT2
RPT1
Alarm Setting
1
1
1
1
1
Once per Second
1
1
1
1
0
Once per Minute
1
1
1
0
0
Once per Hour
1
1
0
0
0
Once per Day
1
0
0
0
0
Once per Month
0
0
0
0
0
Once per Year
16/32
M48T212Y, M48T212V
Figure 9. Back-up Mode Alarm Waveforms
tREC
VCC
VPFD (max)
VPFD (min)
AFE Bit/ABE Bit
AF Bit in Flags Register
IRQ/FT
HIGH-Z
HIGH-Z
AI03622
Watchdog Timer
The watchdog timer can be used to detect an outof-control microprocessor. The user programs the
watchdog timer by setting the desired amount of
time-out into the Watchdog Register, address 7h.
Bits BMB4-BMB0 store a binary multiplier and the
two lower-order bits RB1-RB0 select the resolution, where 00=1/16 second, 01=1/4 second, 10=1
second, and 11=4 seconds. The amount of timeout is then determined to be the multiplication of
the five-bit multiplier value with the resolution. (For
example: writing 00001110 in the Watchdog Register = 3*1 or 3 seconds).
Note: Accuracy of timer is within ± the selected
resolution.
If the processor does not reset the timer within the
specified period, the M48T212Y/V sets the WDF
(Watchdog Flag) and generates a watchdog interrupt or a microprocessor reset. WDF is reset by
reading the Flags Register (Address 0h).
The most significant bit of the Watchdog Register
is the Watchdog Steering Bit (WDS). When set to
a '0.' the watchdog will activate the IRQ/FT pin
when timed-out. When WDS is set to a '1,' the
watchdog will output a negative pulse on the RST
pin for 40 to 200 ms. The Watchdog register, AFE,
ABE, and FT Bits will reset to a '0' at the end of a
Watchdog time-out when the WDS Bit is set to a
'1.'
The watchdog timer can be reset by two methods:
1. a transition (high-to-low or low-to-high) can be
applied to the Watchdog Input pin (WDI) or
2. the microprocessor can perform a WRITE of
the Watchdog Register.
The time-out period then starts over. The WDI pin
should be tied to VSS if not used. The watchdog
will be reset on each transition (edge) seen by the
WDI pin. In the order to perform a software reset
of the watchdog timer, the original time-out period
can be written into the Watchdog Register, effectively restarting the count-down cycle.
Should the watchdog timer time-out, and the WDS
Bit is programmed to output an interrupt, a value of
00h needs to be written to the Watchdog Register
in order to clear the IRQ/FT pin. This will also disable the watchdog function until it is again programmed correctly. A READ of the Flags Register
will reset the Watchdog Flag (Bit D7; Register 0h).
The watchdog function is automatically disabled
upon power-down and the Watchdog Register is
cleared. If the watchdog function is set to output to
the IRQ/FT pin and the frequency test function is
activated, the watchdog or alarm function prevails
and the frequency test function is denied.
17/32
M48T212Y, M48T212V
VCC Switch Output
Vccsw output goes low when VOUT switches to
VCC turning on a customer supplied P-Channel
MOSFET (see Figure 4., page 7). The Motorola
MTD20P06HDL is recommended. This MOSFET
in turn connects VOUT to a separate supply when
the current requirement is greater than IOUT1 (see
Table 14., page 25). This output may also be used
simply to indicate the status of the internal battery
switchover comparator, which controls the source
(VCC or battery) of the VOUT output.
Power-on Reset
The M48T212Y/V continuously monitors VCC.
When VCC falls to the power fail detect trip point,
the RST pulls low (open drain) and remains low on
power-up for trec after VCC passes VPFD (max).
The RST pin is an open drain output and an appro-
priate pull-up resistor to VCC should be chosen to
control rise time.
Note: If the RST output is fed back into either of
the RSTIN inputs (for a microprocessor with a bidirectional reset) then a 1kΩ (max) pull-up resistor
is recommended.
Reset Inputs (RSTIN1 & RSTIN2)
The M48T212Y/V provides two independent inputs which can generate an output reset. The duration and function of these resets is identical to a
reset generated by a power cycle. Table 9 and Figure 10 illustrate the AC reset characteristics of this
function. During the time RST is enabled (tR1HRH
& tR2HRH), the Reset Inputs are ignored.
Note: RSTIN1 and RSTIN2 are each internally
pulled up to VCC through a 100KΩ resistor.
Figure 10. (RSTIN1 & RSTIN2) Timing Waveforms
RSTIN1
tR1
RSTIN2
tR2
RST
tR2HRH
tR1HRH
AI02642
Table 9. Reset AC Characteristics
Symbol
Parameter(1)
Min
Max
Unit
tR1(2)
RSTIN1 Low to RSTIN1 High
200
ns
tR2(3)
RSTIN2 Low to RSTIN2 High
100
ms
tR1HRH(4)
RSTIN1 High to RST High
40
200
ms
tR2HRH(4)
RSTIN2 High to RST High
40
200
ms
Note: 1.
2.
3.
4.
18/32
Valid for Ambient Operating Temperature: TA = 0 to 70°C or –40 to 85°C; VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
Pulse width less than 50ns will result in no RESET (for noise immunity).
Pulse width less than 20ms will result in no RESET (for noise immunity).
CL = 5pF (see Figure 14., page 24).
M48T212Y, M48T212V
Calibrating the Clock
The M48T212Y/V is driven by a quartz controlled
oscillator with a nominal frequency of 32,768 Hz.
The devices are tested not to exceed ±35 ppm
(parts per million) oscillator frequency error at
25°C, which equates to about ±1.53 minutes per
month (see Figure 11., page 21). When the Calibration circuit is properly employed, accuracy improves to better than +1/–2 ppm at 25°C.
The oscillation rate of crystals changes with temperature. The M48T212Y/V design employs periodic counter correction. The calibration circuit
adds or subtracts counts from the oscillator divider
circuit at the divide by 256 stage, as shown in Figure 12., page 21. The number of times pulses
which are blanked (subtracted, negative calibration) or split (added, positive calibration) depends
upon the value loaded into the five Calibration bits
found in the Control Register. Adding counts
speeds the clock up, subtracting counts slows the
clock down.
The Calibration bits occupy the five lower-order
bits (D4-D0) in the Control Register 8h. These bits
can be set to represent any value between 0 and
31 in binary form. Bit D5 is a Sign Bit; '1' indicates
positive calibration, ‘0' indicates negative calibration. Calibration occurs within a 64 minute cycle.
The first 62 minutes in the cycle may, once per
minute, have one second either shortened by 128
or lengthened by 256 oscillator cycles.
If a binary ‘1' is loaded into the register, only the
first 2 minutes in the 64 minute cycle will be modified; if a binary 6 is loaded, the first 12 will be affected, and so on.
Therefore, each calibration step has the effect of
adding 512 or subtracting 256 oscillator cycles for
every 125,829,120 actual oscillator cycles, that is
+4.068 or –2.034 ppm of adjustment per calibration step in the calibration register. Assuming that
the oscillator is running at exactly 32,768 Hz, each
of the 31 increments in the Calibration byte would
represent +10.7 or –5.35 seconds per month
which corresponds to a total range of +5.5 or –2.75
minutes per month.
Two methods are available for ascertaining how
much calibration a given M48T212Y/V may require. The first involves setting the clock, letting it
run for a month and comparing it to a known accurate reference and recording deviation over a fixed
period of time. Calibration values, including the
number of seconds lost or gained in a given period, can be found in Application Note, “AN934,
TIMEKEEPER® Calibration.”
This allows the designer to give the end user the
ability to calibrate the clock as the environment requires, even if the final product is packaged in a
non-user serviceable enclosure. The designer
could provide a simple utility that accesses the
Calibration byte.
The second approach is better suited to a manufacturing environment, and involves the use of the
IRQ/FT pin. The pin will toggle at 512Hz, when the
Stop Bit (ST, D7 of 9h) is '0,' the Frequency Test
Bit (FT, D6 of Ch) is '1,' the Alarm Flag Enable Bit
(AFE, D7 of 6h) is '0,' and the Watchdog Steering
Bit (WDS, D7 of 7h) is '1' or the Watchdog Register
(7h=0) is reset.
Any deviation from 512 Hz indicates the degree
and direction of oscillator frequency shift at the test
temperature. For example, a reading of
512.010124 Hz would indicate a +20 ppm oscillator frequency error, requiring a –10 (WR001010)
to be loaded into the Calibration Byte for correction. Note that setting or changing the Calibration
Byte does not affect the Frequency test output frequency.
The IRQ/FT pin is an open drain output which requires a pull-up resistor to VCC for proper operation. A 500-10kΩ resistor is recommended in order
to control the rise time. The FT Bit is cleared on
power-up.
19/32
M48T212Y, M48T212V
Battery Low Warning
The M48T212Y/V automatically performs battery
voltage monitoring upon power-up and at factoryprogrammed time intervals of approximately 24
hours. The Battery Low (BL) Bit, Bit D4 of Flags
Register 0h, will be asserted if the battery voltage
is found to be less than approximately 2.5V. The
BL Bit will remain asserted until completion of battery replacement and subsequent battery low
monitoring tests, either during the next power-up
sequence or the next scheduled 24-hour interval.
If a battery low is generated during a power-up sequence, this indicates that the battery is below approximately 2.5 volts and may not be able to
maintain data integrity in the SRAM. Data should
be considered suspect and verified as correct. A
fresh battery should be installed.
If a battery low indication is generated during the
24-hour interval check, this indicates that the battery is near end of life. However, data is not compromised due to the fact that a nominal VCC is
supplied. In order to insure data integrity during
subsequent periods of battery back-up mode, the
battery should be replaced. The SNAPHAT® battery/crystal top should be replaced with VCC powering the device to avoid data loss.
Note: this will cause the clock to lose time during
the time interval the battery crystal is removed.
The M48T212Y/V only monitors the battery when
a nominal VCC is applied to the device. Thus applications which require extensive durations in the
battery back-up mode should be powered-up periodically (at least once every few months) in order
for this technique to be beneficial.
Additionally, if a battery low is indicated, data integrity should be verified upon power-up via a
checksum or other technique.
Initial Power-on Defaults
Upon application of power to the device, the following register bits are set to a ’0' state: WDS,
BMB0-BMB4, RB0-RB1, AFE, ABE, W, and FT
(see Tabel 10).
Table 10. Default Values
W
R
FT
AFE
ABE
WATCHDOG
Register(1)
Initial Power-up
(Battery Attach for SNAPHAT)(2)
0
0
0
0
0
0
RESET (3)
0
0
0
0
0
0
Power-down (4)
0
1
0
1
1
0
Subsequent Power-up
0
1
0
0
0
0
Condition
Note: 1.
2.
3.
4.
20/32
WDS, BMB0-BMB4, RB0, RB1.
State of other control bits undefined.
State of other control bits remains unchanged.
Assuming these bits set to '1' prior to power-down.
M48T212Y, M48T212V
Figure 11. Crystal Accuracy Across Temperature
Frequency (ppm)
20
0
–20
–40
–60
–80
–100
∆F = -0.038 ppm (T - T )2 ± 10%
0
F
C2
–120
T0 = 25 °C
–140
–160
–40
–30
–20
–10
0
10
20
30
40
50
60
70
80
Temperature °C
AI00999
Figure 12. Calibration Waveform
NORMAL
POSITIVE
CALIBRATION
NEGATIVE
CALIBRATION
AI00594B
21/32
M48T212Y, M48T212V
VCC Noise And Negative Going Transients
ICC transients, including those produced by output
switching, can produce voltage fluctuations, resulting in spikes on the VCC bus. These transients
can be reduced if capacitors are used to store energy which stabilizes the VCC bus. The energy
stored in the bypass capacitors will be released as
low going spikes are generated or energy will be
absorbed when overshoots occur. A ceramic bypass capacitor value of 0.1µF (as shown in Figure
13) is recommended in order to provide the needed filtering.
In addition to transients that are caused by normal
SRAM operation, power cycling can generate negative voltage spikes on VCC that drive it to values
below VSS by as much as one volt. These negative
spikes can cause data corruption in the SRAM
while in battery backup mode. To protect from
these voltage spikes, STMicroelectronics recommends connecting a schottky diode from VCC to
VSS (cathode connected to VCC, anode to VSS).
Schottky diode 1N5817 is recommended for
through hole and MBRS120T3 is recommended
for surface mount.
22/32
Figure 13. Supply Voltage Protection
VCC
VCC
0.1µF
DEVICE
VSS
AI02169
M48T212Y, M48T212V
MAXIMUM RATING
Stressing the device above the rating listed in the
“Absolute Maximum Ratings” table may cause
permanent damage to the device. These are
stress ratings only and operation of the device at
these or any other conditions above those indicated in the Operating sections of this specification is
not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device
reliability.
Refer
also
to
the
STMicroelectronics SURE Program and other relevant quality documents.
Table 11. Absolute Maximum Ratings
Symbol
TA
TSTG
TSLD(1,2)
Parameter
Value
Unit
0 to 70
°C
SNAPHAT®
–40 to 85
°C
SOIC
–55 to 125
°C
260
°C
–0.3 to VCC + 0.3
V
M48T212Y
–0.3 to 7.0
V
M48T212V
–0.3 to 4.6
V
Ambient Operating Temperature
Storage Temperature
Lead Solder Temperature for 10 seconds
VIO
Input or Output Voltage
VCC
Supply Voltage
IO
Output Current
20
mA
PD
Power Dissipation
1
W
Note: 1. For SO package, standard (SnPb) lead finish: Reflow at peak temperature of 225°C (total thermal budget not to exceed 180°C for
between 90 to 150 seconds).
2. For SO package, Lead-free (Pb-free) lead finish: Reflow at peak temperature of 260°C (total thermal budget not to exceed 245°C
for greater than 30 seconds).
CAUTION: Negative undershoots below –0.3V are not allowed on any pin while in the Battery Back-up mode.
CAUTION: Do NOT wave solder SOIC to avoid damaging SNAPHAT sockets.
23/32
M48T212Y, M48T212V
DC AND AC PARAMETERS
This section summarizes the operating and measurement conditions, as well as the DC and AC
characteristics of the device. The parameters in
the following DC and AC Characteristic tables are
derived from tests performed under the Measure-
ment Conditions listed in the relevant tables. Designers should check that the operating conditions
in their projects match the measurement conditions when using the quoted parameters.
Table 12. DC and AC Measurement Conditions
Parameter
M48T212Y
M48T212V
4.5 to 5.5V
3.0 to 3.6V
Grade 1
0 to 70°C
0 to 70°C
Grade 6
–40 to 85°C
–40 to 85°C
Load Capacitance (CL)
100pF
50pF
Input Rise and Fall Times
≤ 5ns
≤ 5ns
0 to 3V
0 to 3V
1.5V
1.5V
Max
Unit
Input Capacitance
10
pF
Input/Output Capacitance
10
pF
VCC Supply Voltage
Ambient Operating Temperature
Input Pulse Voltages
Input and Output Timing Ref. Voltages
Note: Output High Z is defined as the point where data is no longer driven.
Figure 14. AC Testing Load Circuit
645Ω
DEVICE
UNDER
TEST
CL = 100pF or 5pF (1)
CL = 30 pF (2)
1.75V
CL includes JIG capacitance
AI03239
Note: Excluding open-drain output pins; 50pF for M48T212V.
1. DQ0-DQ7
2. E1CON and E2CON
Table 13. Capacitance
Symbol
CIN
COUT(3)
Parameter(1,2)
Min
Note: 1. Effective capacitance measured with power supply at 5V (M48T212Y) or 3.3V (M48T212V); sampled only, not 100% tested.
2. At 25°C, f = 1MHz.
3. Outputs deselected.
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M48T212Y, M48T212V
Table 14. DC Characteristics
Sym
Parameter
(1)
Test Condition
Min
ILI(2)
Input Leakage Current
ILO(3)
Output Leakage Current
M48T212Y
M48T212V
–70
–85
Typ
Max
Min
Typ
Unit
Max
0V ≤ VIN ≤ VCC
±1
±1
µA
0V ≤ VOUT ≤ VCC
±1
±1
µA
10
mA
ICC
Supply Current
ICC1
Supply Current (Standby)
TTL
E = VIH
5
3
mA
ICC2
Supply Current (Standby)
CMOS
E = VCC –0.2
3
2
mA
Outputs open
8
Battery Current OSC ON
IBAT
Battery Current OSC
ON(4)
VCC = 0V
15
4
575
800
575
800
nA
950
1250
950
1250
nA
100
nA
Battery Current OSC
OFF
100
VIL
Input Low Voltage
–0.3
0.8
–0.3
0.8
V
VIH
Input High Voltage
2.2
VCC +
0.3
2.0
VCC +
0.3
V
Output Low Voltage
IOL = 2.1mA
0.4
0.4
V
Output Low Voltage
(open drain) (5)
IOL = 10mA
0.4
0.4
V
Output High Voltage
IOH = –1.0mA
2.4
VOHB(6) VOH Battery Back-up
IOUT2 = –1.0µA
2.0
IOUT1(7) VOUT Current (Active)
VOUT1 > VCC –0.3
IOUT2
VOUT Current (Battery
Back-up)
VOUT2 > VBAT –0.3
VPFD
Power-fail Deselect
Voltage
VSO
Battery Back-up
Switchover Voltage
3.0
VPFD –
100mV
V
VBAT
Battery Voltage
3.0
3.0
V
VOL
VOH
4.2
2.4
3.6
4.35
V
3.6
V
100
70
mA
100
100
µA
3.0
V
4.5
2.0
2.7
2.9
Note: 1.
2.
3.
4.
5.
6.
Valid for Ambient Operating Temperature: TA = 0 to 70°C or –40 to 85°C; VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
RSTIN1 and RSTIN2 internally pulled-up to VCC through 100KΩ resistor. WDI internally pulled-down to VSS through 100KΩ resistor.
Outputs deselected.
IBAT (OSC ON) = Industrial Temperature Range - Grade 6 device.
For IRQ/FT & RST pins (Open Drain).
Conditioned outputs (E1CON - E2CON) can only sustain CMOS leakage currents in the battery back-up mode. Higher leakage currents will reduce battery life.
7. External SRAM must match TIMEKEEPER® SUPERVISOR chip VCC specification.
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M48T212Y, M48T212V
Figure 15. Power Down/Up Mode AC Waveforms
VCC
VPFD (max)
VPFD (min)
VSO
tF
tR
tFB
INPUTS
VALID
OUTPUTS
VALID
tRB
trec
VALID
DON'T CARE
HIGH-Z
VALID
RST
VCCSW
AI02638
Table 15. Power Down/Up Mode AC Characteristics
Parameter(1)
Symbol
tF
VPFD (max) to VPFD (min) VCC Fall Time
tFB
VPFD (min) to VSS VCC Fall Time
tR
Min
Max
Unit
300
µs
M48T212Y
10
µs
M48T212V
150
µs
VPFD (min) to VPFD (max) VCC Rise Time
10
µs
tRB
VSS to VPFD (min) VCC Rise Time
1
µs
trec
VPFD (max) to RST High
40
200
ms
Note: 1. Valid for Ambient Operating Temperature: TA = 0 to 70°C or –40 to 85°C; VCC = 4.5 to 5.5V or 3.0 to 3.6V (except where noted).
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M48T212Y, M48T212V
PACKAGE MECHANICAL INFORMATION
Figure 16. SOH44 – 44-lead Plastic Small Outline, SNAPHAT, Package Outline
A2
A
C
B
eB
e
CP
D
N
E
H
A1
α
L
1
SOH-A
Note: Drawing is not to scale.
Table 16. SOH44 – 44-lead Plastic Small Outline, SNAPHAT, Package Mechanical Data
mm
inches
Symb
Typ
Min
A
Max
Typ
Min
3.05
Max
0.120
A1
0.05
0.36
0.002
0.014
A2
2.34
2.69
0.092
0.106
B
0.36
0.46
0.014
0.018
C
0.15
0.32
0.006
0.012
D
17.71
18.49
0.697
0.728
E
8.23
8.89
0.324
0.350
–
–
–
–
eB
3.20
3.61
0.126
0.142
H
11.51
12.70
0.453
0.500
L
0.41
1.27
0.016
0.050
α
0°
8°
0°
8°
N
44
e
CP
0.81
0.032
44
0.10
0.004
27/32
M48T212Y, M48T212V
Figure 17. SH – 4-pin SNAPHAT Housing for 48 mAh Battery & Crystal, Package Outline
A1
A2
A3
A
eA
B
L
eB
D
E
SHTK-A
Note: Drawing is not to scale.
Table 17. SH – 4-pin SNAPHAT Housing for 48 mAh Battery & Crystal, Package Mech. Data
mm
inches
Symb
Typ
Min
A
Typ
Min
9.78
Max
0.385
A1
6.73
7.24
0.265
0.285
A2
6.48
6.99
0.255
0.275
A3
28/32
Max
0.38
0.015
B
0.46
0.56
0.018
0.022
D
21.21
21.84
0.835
0.860
E
14.22
14.99
0.560
0.590
eA
15.55
15.95
0.612
0.628
eB
3.20
3.61
0.126
0.142
L
2.03
2.29
0.080
0.090
M48T212Y, M48T212V
Figure 18. SH – 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Outline
A1
A2
A3
A
eA
B
L
eB
D
E
SHTK-A
Note: Drawing is not to scale.
Table 18. SH – 4-pin SNAPHAT Housing for 120mAh Battery & Crystal, Package Mech. Data
mm
inches
Symb
Typ
Min
A
Max
Typ
Min
10.54
Max
0.415
A1
8.00
8.51
0.315
.0335
A2
7.24
8.00
0.285
0.315
A3
0.38
0.015
B
0.46
0.56
0.018
0.022
D
21.21
21.84
0.835
0.860
E
17.27
18.03
0.680
.0710
eA
15.55
15.95
0.612
0.628
eB
3.20
3.61
0.126
0.142
L
2.03
2.29
0.080
0.090
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M48T212Y, M48T212V
PART NUMBERING
Table 19. Ordering Information Example
Example:
M48T
212Y
–70
MH
1
TR
Device Type
M48T
Supply and Write Protect Voltage
212Y = VCC = 4.5 to 5.5V; 4.2V ≤ VPFD ≤ 4.5V
212V = VCC = 3.0 to 3.6V; 2.7V ≤ VPFD ≤ 3.0V
Speed
–70 = 70ns (for M48T212Y)
–85 = 85ns (for M48T212V)
Package
MH(1) = SOH44
Temperature Range
1 = 0 to 70°C
6 = –40 to 85°C
Shipping Method
blank = Tubes (Not for New Design - Use E)
E = Lead-free Package (ECO
PACK®), Tubes
F = Lead-free Package (ECO
PACK®), Tape & Reel
TR = Tape & Reel (Not for New Design - Use F)
Note: 1. The SOIC package (SOH44) requires the SNAPHAT® battery package which is ordered separately under the part number
“M4Txx-BR12SH” in plastic tube or “M4Txx-BR12SHTR” in Tape & Reel form (see Table 20).
Caution: Do not place the SNAPHAT battery package “M4Txx-BR12SH” in conductive foam as it will drain the lithium button-cell battery.
For other options, or for more information on any aspect of this device, please contact the ST Sales Office
nearest you.
Table 20. SNAPHAT® Battery Table
Part Number
30/32
Description
Package
M4T28-BR12SH
Lithium Battery (48mAh) SNAPHAT
SH
M4T32-BR12SH
Lithium Battery (120mAh) SNAPHAT
SH
M48T212Y, M48T212V
REVISION HISTORY
Table 21. Document Revision History
Date
Rev. #
Revision Details
October 1999
1.0
First Issue
01-Mar-00
2.0
Document Layout changed; Default Values table added (Table 10)
21-Apr-00
3.0
From Preliminary Data to Data Sheet
10-Nov-00
3.1
Table 16 changed
30-May-01
3.2
Changed “Controller” references to “SUPERVISOR”
10-Sep-01
4.0
Reformatted; added temp./voltage info. to tables (Table 14, 5, 6, 15, 9); added E2 to
Hookup (Figure 4); Improve text in “Setting the Alarm Clock” section
13-May-02
4.1
Modify reflow time and temperature footnote (Table 11)
16-Jul-02
4.1
Updated DC Characteristics, footnotes (Table 14)
27-Mar-03
5.0
v2.2 template applied; updated test condition (Table 14)
31-Mar-04
6.0
Reformatted; updated with Pb-free information (Table 11, 19)
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M48T212Y, M48T212V
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics.
All other names are the property of their respective owners.
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