serial real-time clock (rtc) ics - rs components...time stamp, anti-tamper for secure applications,...
TRANSCRIPT
Serial real-time clock (RTC) ICs
Content
Real-time clock (RTC) ICs spectrum ................................... 3
Low-power real-time clocks for portable devices ........... 4World’s smallest RTC with embedded crystal .................................. 5
Enhanced industry-standard real-time clocks ............... 6Highly accurate, automatic temperature-compensated real-time clock solution with embedded crystal ............................. 6Real-time clocks with analog calibration ........................................ 8
Highly-integrated real-time clocks ................................... 10Combined RTC and microprocessor supervisor ........................... 10Securitizor ..................................................................................... 12
Design support ........................................................................ 16
Widest portfolio of real-time clocks offers unlimited designs solutions
An extended variety of products with the newest technology innovations are available including ultra-low-power devices, the world’s smallest package with embedded crystal, ST’s SNAPHAT® with battery and crystal integrated. RTC functions include alarm, battery switchover, reset, and special features with time stamp, anti-tamper for secure applications, audio, and trickle charge, and an highly-accurate temperature-compensated RTC with embedded crystal.
RTC ICs spectrum
3
Integration
• Low standby current
• World’s smallest RTC with crystal
• Small packages
Low-power for portable devices
• Automatic battery switchover
• Analog calibration
• Embedded crystal
• Temperature-compensated RTC
Enhanced industry-standard
• RTC with NVRAM and microprocessor supervisor functions
• Battery monitor
• Power-on reset/low-voltage detect
Highly-integrated
• Physical tamper detect
• Internal and external RAM clear
• Tamper event timestamp
Securitizor
M41T6x series M41T81S, M41T00S, M41T82/83/93, M41T00CAP, M41TC8025
M41ST85W, M41T94, M41T00AUD
M41ST87W
4
Low-power RTC ICs
Very low standby current extends battery backup life
Special low-power RTC series available in small packages, from 350 nA, with battery switchover, and with or without an embedded crystal to best fit battery-operated device constraints.
Low-powEr rTCs for porTabLE dEviCES porTfoLio
M41T6x• 10ths and 100ths of seconds
• 350 nA standby (typ) at 3.0 V
• 1.3 to 4.4 V operation • 4.4 V max VCC suitable for lithium-ion battery operation
• Timekeeping down to 1.0 V
• 400 kHz I2C Interface
• Programmable watchdog output • 62.5 ms to 31 min • Dedicated output
appLiCaTion ExaMpLES • Digital cameras
• Portable media players
• Medical instruments
• Point-of-sale terminals
• Test equipment
• Portable navigation
• BCD registers for year, month, day, date, hours, minutes and seconds
• 2 century bits (Y2.1 K compliant)
• Automatic leap year adjustment
• Calibration register
• Oscillator fail detect
3 mm
3 mm
0.90 mm
M41T6x
QFN16
part number
package
battery supply current (ibat)
data bus type
400 kHz
Supply voltage
Timekeepingoscillator fail detect
programmable alarms
watchdog timer
Square wave
dedicated ouput
power-up output
frequency (kHz)
Embedded crystal
typ (na)min - max
(v)min (v)
M41T60 QFN16 350 I2C 1.3 - 4.4 1 •1 - - - -
M41T62QFN16 350 I2C 1.3 - 4.4 1 •1 •1 •1 • 32
LCC8 350 I2C 1.3 - 4.4 1 •1 •1 •1 • 32 •
M41T63 QFN16 350 I2C 1.3 - 4.4 1 • - • • 32
M41T64 QFN16 350 I2C 1.3 - 4.4 1 • - • • 32
M41T65 QFN16 350 I2C 1.3 - 4.4 1 •1 •1 • - -
M41T66 QFN16 525 I2C 1.5 - 4.4 1 •1 •1 •1 • 32
Note: 1: With IRQ output
5
worLd’S SMaLLEST rTC wiTH EMbEddEd CrySTaL
M41T62LC6f • RTC in LCC8 package with
embedded crystal
• 10ths and 100ths of seconds
• Programmable alarm with repeat modes and interrupt function
• Programmable watchdog timer • 62.5 ms to 31 min
• Programmable square-wave output • 1 Hz to 32 KHz • 32 KHz and on at power-up (can be disabled)
LCC8
1.5 mm 3.2 mm
Oscillatorfail detect
Out
Square waveCalibration
OFIE
Seconds0.1 Seconds0.01 SecondsCentury bits
AlarmWatchdog
MinutesHoursDateDay
MonthYear
400 kHzI²C
interface
VCC
Microcontroller I²C
I²C
XI
VCC
XO
2
M41T62
IRQ/OUT(Open drain)
SQW
32 KHzoscillator
HigHLy aCCuraTE, auToMaTiC TEMpEraTurE-CoMpEnSaTEd rEaL-TiME CLoCkSoLuTion wiTH EMbEddEd CrySTaLMore applications now require very accurate timekeeping across a wide range of temperature. Multi-rate smart power metering is a typical example,since power companies need to log multi-rate electricity usage for accurate billing. Applications: Smart metering and industrial.
6
Enhanced industry-standard
Class-leading RTCs for smart utility meters and precision applications
Enhanced industry-standard RTC with fixed reference added for highly-reliable battery switchover threshold, plus analog calibration, embedded crystal and oscillator fail detect.
M41TC8025 • Embedded high-stability 32 KHz DTCXO
• Temperature-compensated serial real-time clock • ±5.0 ppm max from -40 to 85 °C • ±3.8 ppm max from 0 to 50 °C
• Supply voltage • Clock operating & timekeeping: 1.6 to 5.5 V • I2C interface operating: 1.8 to 5.5 V • Temperature compensation: 2.2 to 5.5 V
• 0.8 μA typical current at 3.0 V supply voltage
• 400 kHz I2C interface
• Time-of-day alarm (with interrupt)
• Fixed-cycle timer interrupt function
• Time update interrupt function
• Programmable frequency output • F
OUT = 1 Hz, 1 KHz and 32 KHz
• Registers for seconds, minutes, hours, day-of week, date (day of month), month and year with automatic leap year compensation
• Programmable temperature compensation intervals (0.5 s, 2 s default, 10 s, 30 s)
SO14
32 KHztemp-compensated
OSC & capacitor array
Tempsensor
Interruptcontrol
UIE TIE AIETime update
Fixed-cycle timer
Alarm compare
Clock registers
Alarm registers
Non-clock registers
Compensationcontrol
Counter 0 - 99
Counter 1 - 12
Counter 1 - 7Counter 1 - 31
Counter 0 - 23
Counter 0 - 59
Divide by32768
Counter 0 - 59
1 Hz
32 KHz
32 KHz
1 KHz
1 HzSecondsMinutesHours
DateDay-of-week
MonthYear
VCCFOUTSQW
FOE
VSS
SDASCL
I²Cinterface
Time counter 0
Extension regTime counter 1
Flag registerControl reg
Hour alarmMin alarm
Day/week alarmDate alarm
M41TC8025
IRQ
7
M41T00S• Precision reference for battery
switchover threshold
• Oscillator fail detect circuit
• 400 kHz I2C interface
• Automatic battery switchover and write-protect
• Calibration register - accuracy to 5 seconds per month
• BCD registers: century, year, month, day, date, hours, minutes, seconds
• 2.7 to 5.5 V operation
• Automatic leap year adjustment
• SO8 package
M41T81S • Precision reference for battery
switchover threshold
• Programmable alarm with repeat modes
• Oscillator fail detect circuit
• Battery monitor
• Automatic battery switchover and write-protect
• Calibration register - accuracy to 5 seconds per month
• BCD registers: century, year, month, day, date, hours, minutes, seconds
• 400 kHz I2C interface
• Programmable watchdog • 62.5 ms to 128 s time-out
• Programmable square-wave • 1 Hz to 32 KHz
• Automatic leap year adjustment
M41T00Cap• Integrated backup battery and
embedded crystal
• Based on M41T00S RTC
• CAPHAT™ PCDIP24 package
• 0 to 70 °C operation
• Up to 10 years of timekeeping without system power
M41T00aud• RTC with integrated audio amplifier
• 400 kHz I2C interface
• DFN16 (5 x 4 mm) package
• 0 to 70 °C operation
• 400 nA backup current
• 3.0 to 3.6 V operation
• Automatic battery switchover
• Oscillator fail detect
• Trickle charge circuit for backup capacitor
• Timekeeping down to 1.7 V
audio fEaTurES• 300 mW differential audio amplifier
• 256 and 512 Hz tone generation
• Gain adjustment from - 33 to +12 dB in 3 dB steps
• Automatic shut off in backup mode
PCDIP24 CAPHAT™Embedded crystal + battery (internal view)
XI
XO
Oscillatorfail detect
SecondsCentury bitsCalibration
Out
MinutesHoursDateDay
MonthYear
VCC
Microcontroller
VCC
400 KHzI²C
interfaceI²C
I²C2
M41T00S
32 KHzoscillator
ReferenceVPFD = 2.6 V
FT/OUT/OSC-FAIL-IRQ
Automaticbattery
switchoverand writeprotect
SO8
XI
XO
Oscillatorfail detect
SecondsCentury bitsCalibration
0.1 Seconds0.01 Seconds
AlarmWatchdog
Square wave
Out
MinutesHoursDateDay
MonthYear
VCC
Microcontroller
VCC
400 KHzI²C
interfaceI²C
I²C2
M41T81S
ReferenceVPFD = 2.6 V
Batterymonitor
Automaticbattery
switchoverand writeprotect
FREQ-TEST/ALARM/W-DOG/SQ-WAVE/OSC-FAIL-IRQ/OUT
32 KHzoscillator
SOX18 Embedded crystal
(Internal view)
8
rEaL-TiME CLoCkS wiTH anaLog CaLibraTion M41T83, M41T93 • Dual calibration features • Analog calibration • 5 ppm typical at 25 °C after two reflows • Real-time feedback • Pre-programmed in OTP byte (only in SOX18) • Digital calibration
• 365 nA standby (typ) at 3.0 V
• Automatic battery switchover and write-protect • Precision reference
• 400 kHz I2C, 10 MHz SPI
• 12 bytes of NVRAM • 5 bytes shared with 2 alarm registers
• 2 programmable alarms with repeat modes
• Memory-mapped BCD year, month, day, date, hours, minutes, seconds, 10ths, 100ths of seconds
• 2.38 to 5.5 V operation • Timekeeping down to 1.8 V • Three V
PFD (V
RST) options:
• 2.93 VPFD
@ 3.0 to 5.5 VCC
• 2.63 V
PFD @ 2.7 to 5.5 V
CC
• 2.32 VPFD
@ 2.38 to 5.5 VCC
• Programmable watchdog (62.5 ms to 128 s)
• Programmable squarewave output • 1 Hz to 32 KHz • 32 KHz on at power-up (can be disabled)
M41T82 • Light version of M41T83, pin-to-pin
compatible with earlier RTCs in SO8 packages
• Dual calibration features • Analog calibration - real-time feedback • Digital calibration
• Automatic battery switchover and write-protect • Precision reference
• 400 kHz I2C
• 365 nA standby (typ) at 3.0 V
• 12 bytes of NVRAM
• 2.38 to 5.5 V operation • Timekeeping down to 1.8 V • Three VPFD (VRST) options: • 2.93 V
PFD @ 3.0 to 5.5 V
CC
• 2.63 VPFD
@ 2.7 to 5.5 VCC
• 2.32 V
PFD @ 2.38 to 5.5 V
CC
• Memory-mapped BCD year, month, day, date, hours, minutes, seconds • 10ths, 100ths of seconds
MonthYear
Seconds2 Century bits0.1 Seconds0.01 SecondsA. cal (REG)A. cal (OTP)
Oscillatorfail detect
Auto-reload8-bit tmr/cntr
Alarm1D. cal
Alarm2Watchdog
Out
NVRAM12 bytes
Square ware
MinutesHoursDateDay
VCC VBAT
Microcontroller
VCC
400 KHz I²C T83SPI: T93I²C/
SPI
I²C/SPI
2/4
M41T83, M41T93
Automatic batteryswitchover andwrite protect
ReferenceVPFD (VRST) = 2.6 V
Batterymonitor
IRQ/FT/OUT(W-DOG/ALARM-IRQ/FT/OUT/OSC-FAIL-IRQ/TIMER-IRQ)
IRQ2
SQW(Defaultsto 32 KHzand on; canbe disabled)
OTP onlyon SOX18package
POR/LVD
(SOX18only)
VPP
32 KHzoscillator
SOX18Embedded crystal
(internal view)4 mm
4 mm
0.90 mm QFN16
M41T83
MonthYear
Seconds2 Century bits0.1 Seconds0.01 Seconds
Analog cal
Oscillatorfail detect
Auto-reload8-bit tmr/cntr
Digital cal
NVRAM12 bytes
MinutesHoursDateDay
VCC VBAT
Microcontroller
XI
XO
VCC M41T82
Automatic batteryswitchover andwrite protect
ReferenceVPFD (VRST) = 2.6 V
Batterymonitor
POR/LVD
400 KHz I²CI²C
I²C
2
32 KHzoscillator
SO8
9
appLiCaTion ExaMpLES • Home multimedia
• Metering (gas, electricity, water)
• Multi-function printers
• Vehicle tracking systems
part number
pack
age
battery supply current (ibat)
nvraMsize data
bus type
vCC
Tim
ekee
ping
min
(v)
b atte
rysw
itcho
ver
osci
llato
r fai
l de
tect
prog
ram
mab
leal
arm
s
Squa
re w
ave
outp
ut
pow
er-u
p ou
tput
fr
eque
ncy
(kHz
)
wat
chdo
gtim
er
batte
ry lo
w
dete
ct
pow
er o
nre
set/
low
volta
ge d
etec
tor
outp
ut
Embe
dded
cry
stal
Tem
pera
ture
co
mpe
nsat
ed
typ (na) (bytes)min -
max (v)
M41T0 SO-8 900 - I²C2 2 - 5.5 2 - • - - - - - - - -
M41T00S SO-8 600 - I²C2 2.7 - 5.5 2 •5 • - - - - - - - -
M41T00aud DFN16 600 - I²C2 3 - 3.6 1.7 •5 •3 - - - - - - - -
M41T00Cap PCDIP241 - - I²C2 2.7 - 5.5 - •5 • - - - - - - • -
M41T11SO-8 800 56 I²C 2 - 5.5 2 • - - - - - - - - -
SOH-28 800 56 I²C 2 - 5.5 2 • - - - - - - - - -
M41T56 SO-8 450 56 I²C 4.5 - 5.5 2.5 • - - - - - - - - -
M41T80 SO-8 1500 - I²C2 2 - 5.5 2 - - •3 •3 324 - - - - -
M41T81SSO-8 600 - I²C2 2.7 - 5.5 2 •5 •3 •3 •3 - •3 • - - -
SOX-18 600 - I²C2 2.7 - 5.5 2 •5 •3 •3 •3 - •3 • - • -
M41T82 SO-8 365 12 I²C2 2.38 - 5.5 1.8 •5 • - - - - • • • -
M41T83QFN16 365 12 I²C2 2.38 - 5.5 1.8 •5 •3 •3 •4 32 •3 • • • -
SOX-18 365 12 I²C2 2.38 - 5.5 1.8 •5 •3 •3 •4 32 •3 • • •
M41T93QFN16 365 12 SPI6 2.38 - 5.5 1.8 •5 •3 •3 •4 32 •3 • • • -
SOX-18 365 12 SPI6 2.38 - 5.5 1.8 •5 •3 •3 •4 32 •3 • • •
M41TC8025 S0-14 800 - I²C 1.6 - 5.5 1.6 - - • • 32 - • • • •
Note:1: Integrated battery and embedded crystal2: 400 kHz3: With IRQ output4: Dedicated output5: Fixed switchover reference6: 10 MHz
EnHanCEd induSTry-STandard rTCs porTfoLio
Long-LifE baTTEry baCkup
48 mah baTTEry 12 yEarS baCkup LifE M41T56 baTTEry baCkup• Backup life t = battery capacity / battery current
• BR1225 capacity = 48 mAh
• M41T56 backup current IBAT = 450 nA (typical)
• Backup life t = BR1225 capacity / IBAT
t = 48 mAh / 450 nA = 106,666.7 hours = 4444.4 days
• Backup life t = 12.2 years
M41T56
VCC
VCC = 5 V
VBATVBAT
BR1225Li coin cell VSS
10
Highly-integrated RTC
Combined RTC and Microprocessor supervisor
Highly-integrated RTCs with NVRAM and a large set of microprocessor supervisory functions, including battery monitor, power-on reset and low-voltage detect.
M41T94 • Automatic battery switchover
• Power-fail detect and write-protect
• 2 MHz SPI bus
• THS pin selects 5 or 3/3.3 V operation
• 400 nA standby (typ) at 3.0 V
• 44 bytes of NVRAM
• Programmable alarm with repeat mode
• Programmable square-wave output • 1 Hz to 32 KHz
• 10ths and 100ths of seconds
MiCroproCESSor SupErviSor funCTionS • Power-on reset/low-voltage detect
• Programmable watchdog • 62.5 ms to 128 s
• Two reset inputs
appLiCaTion ExaMpLES • Servers
• Medical equipment
• Point of sales
• Vending machines
• Gaming
44 BytesNVRAM
Seconds0.1 Seconds0.01 SecondsCentury bitsCalibrationWatchdog
AlarmSquare wave
MinutesHoursDateDay
MonthYear
VCC
VCC
Microprocessor
VCC
VCC
WDI
VSS
VBAT
SPISPI
I/O
4
Power-on reset/low-voltage detectPush-button resetWatchdog reset
M41T94
Automaticbattery
switchover
Batterymonitor
Power-faildetect and
writeprotect
Power-failTHSThreshold
32 KHzoscillator
XTAL
RSTRESET
IRQ
IRQ/FT/OUT
SQW
WDF
AF
RSTIN1RSTIN2
1: VPFD = 4.40 V0: VPFD = 2.65 V
SO16
SOH28
SNAPHAT battery top
11
M41ST85w• 400 kHz I2C
• 400 nA standby (typ) at 3.0 V
• 2.7 to 3.6 V
• 28-lead SNAPHAT® IC (SOH28)
• 28-lead embedded crystal SOIC (SOX28)
• Operating temperature: -40 to +85 °C
• 44 bytes of NVRAM
• Programmable alarm with repeat mode
• Programmable square-wave output • 1 Hz to 32 KHz
• 10ths and 100ths of seconds
MiCroproCESSor SupErviSor funCTionS• Early power-fail warning (PFI/PFO)
with 1.25 V reference
• Power-on reset/low-voltage detect
• Programmable watchdog • 62.5 ms to 128 s
• Two reset inputs
nvraM SupErviSor fEaTurES• Automatic battery switchover and
write-protect • Non-volatile external LPSRAM
• Battery monitor
XTAL
RSTIN1RSTIN2
IRQ/FT/OUTWDFAF
44 BytesNVRAM
Seconds0.1 Seconds0.01 SecondsCentury bitsCalibrationWatchdog
AlarmSquare wave
MinutesHoursDateDay
MonthYear
R1
R2
VCC VCC
LPSRAM256 Kb
to 16 Mb
VOUT
VSS
VBAT
VUNREG
WDI
Power-on reset/low-voltage detectPush-button resetWatchdog reset
M41ST85W
Battery monitorPower-fail
deselect andwrite protect
Real-time clock section
32 KHzoscillator
RST
EX
ECON
SQW
PFO
Early power-failwarning 1.25 V
PFI
VCC
VCC
VUNREG
VPFIMicroprocessor
I/O
ADDR/DATA BUS
RESET
CECE
IRQ
NMI
400 kHz I²CI²C
Regulator Battery backupswitchover
2/4
SNAPHAT battery top
SOH28 SNAPHAT IC
SOX28 Embeddedcrystal (internal view)
12
SECuriTizorCombined real-time clock (RTC) IC including microprocessor supervisor, NVRAM supervisor, with physical tamper detect, plus internal and external RAM clear for secure applications.
M41ST87w • 64-bit unique serial number
• -40 to +85 °C
• 3 V, 3.3 V, 5 V operation
• 500 nA standby (typ) at 3.0 V
• 28-lead embedded crystal IC
• Counters for 10ths and 100ths of seconds, seconds, minutes, hours, day, date, month, year, and century
• 128 bytes of clearable NVRAM
• Programmable alarm with repeat modes functions in battery-backed mode
• Programmable square-wave output • 1 Hz to 32 KHz
• Dedicated 32 KHz output
TaMpEr CirCuiT fEaTurES • Two independent inputs detect circuit
opening or closing. Options on alarm: • Generate interrupt • Clear internal RAM • Clear external RAM • Store event time (always) • Output reset
• Tamper detect functions even in battery-backed mode
• Oscillator fail detect bit indicates oscillator has slowed, and crystal may have been tampered
MiCroproCESSor SupErviSor funCTionS • Programmable watchdog • 62.5 ms to 128 s timeout period
• Power-on reset/low-voltage detect
• Two reset input pins
• Two independent early power-fail warning circuits (PFI/PFO) with 1.25 V precision reference
nvraM SupErviSor fEaTurES • Battery switchover
• Power-fail write protect
• Battery monitor
• Turns LPSRAM into NVRAM
appLiCaTion ExaMpLES • Black boxes
• Closed-circuit TV
• Financial security: ATM, cash, registers, POS, card readers
• Gaming machines
• Fire alarms
• Metering (gas, electricity, water)
SOX28 Embedded crystal(internal view)
SSOP20
M41ST87w appLiCaTion diagraM
128 BytesNvram
Seconds0.1 Seconds0.01 SecondsCentury bitsCalibration
AlarmWatchdog
Square wave64 bit ser. no.
MinutesHoursDateDay
MonthYear
Power-on reset/low-voltage detect
Early power-failwarning (PFI/PFO)
Watchdog
Interrupt
EXT RAM CLR
INT RAM CLR
VCC VBAT
Microprocessor/Microcontroller
/CE
TP1INTP2IN
I²C
Batteryswitchover
Writeprotect
LPSRAM
13
part number
pack
age
battery supply current
(ibat)
nvraMsize data
bus type
vCC
batte
rysw
itcho
ver
osci
llato
r fai
l de
tect
prog
ram
mab
leal
arm
s
Squa
re w
ave
dedi
cate
d ou
tput
pow
er-u
p ou
tput
fr
eque
ncy
(kHz
)
wat
chdo
gtim
er
batte
ry lo
w
dete
ct
pow
er o
nre
set/
low
volta
ge d
etec
tor
outp
ut
pow
er f a
il co
mpa
rato
r
rese
t inp
uts
Embe
dded
cry
stal
typ (na) (bytes)min -
max (v)
M41ST85wSOX-28 400 44 I²C2 2.7 - 3.6 •4 - •3 • - •3 • • • • •
SOH-28 400 44 I²C2 2.7 - 3.6 •4 - •3 • - •3 • • • • •
M41ST87wSSOP 20 500 128 I²C2 2.7 - 3.6 •4 •3 •3 • 32 •3 • • • • •
SOX-28 500 128 I²C2 2.7 - 3.6 •4 •3 •3 • 32 •3 • • • • •
M41T94SO-16 400 44 SPI1 2.7 - 5.5 •4 • •3 • - •3 • • - • •
SOH-28 400 44 SPI1 2.7 - 5.5 •4 • •3 • - •3 • • - • •
Note:1: 2 MHz2: 400 kHz3: With IRQ output4: Fixed switchover reference
HigHLy-inTEgraTEd rTCs porTfoLio
RSTIN1RSTIN2
Tamper ckt 2
128 bytesuser ramWatchdog
Real-time clockwith alarm
Osc monitorSquare wave
64 bitserial numberTamper ckt 1
R1
R2
VCCVCC
Any size -256 Kbytes
to 16 Mbytes
LPSRAMVOUT
VSS
VBAT
VUNREG
WDI
M41ST87W
Real-time clock section
XTAL
TP1INTP2IN
RST
ECON
SQW
TPCLR
/BLRAMCLR
WD
TD1TD2
AF
OF(R
ESET
ON
W-D
OG)
(RES
ET O
N TP
CLR)
IRQ/OUT
PFO1
PFO2
1.25 VREF
PFI1
PFI2
VUNREG
VPFI
ADDR/DATA BUS
EX CE
Debounce
400 KHzI²C interface
32 KHz
Regulator
Power-faildeselect andwrite protect
2
VCC
Microprocessor
RESET
CE
IRQ
NMI
I²C
WDI
Compare
Compare
32 KHzoscillator
Power-failwrite protect
Battery monitor
14
part number packagepackage
sizevCC
min - max ibat typ
Timekeeping min
nvraM oscillator fail detect
features(mm) (v) (na) (v) (bytes)
M41T60 QFN16 3.0x3.0 1.3 - 4.4 350 1 - • I²C
M41T62LCC8
QFN161.5x3.2 3.0x3.0
1.3 - 4.4 350 1 - •Dedicated SQW output, crystal, I2C, programmable alarm,
SQW @ 32 kHz, WDG
M41T63 QFN16 3.0x3.0 1.3 - 4.4 350 1 - •Dedicated SQW and WDG timer output, crystal, I2C,
programmable alarm, SQW @ 32 kHz
M41T64 QFN16 3.0x3.0 1.3 - 4.4 350 1 - •Dedicated SQW output, I2C, programmable alarm,
SQW @ 32 kHz, WDG
M41T65 QFN16 3.0x3.0 1.3 - 4.4 350 1 - • Dedicated WDG timer output, I²C, programmable alarm
M41T66 QFN16 3.0x3.0 1.5 - 4.4 525 1 - •Dedicated SQW output I²C, programmable alarm,
SQW @ 32 kHz, WDG,
M41T0 SO-8 3.9x4.9 2 - 5.5 900 2 - • I²C
M41T00S SO-8 3.9x4.9 2.7 - 5.5 600 2 - • Battery switchover with fixed reference, I²C
M41T00aud DFN16 4.0x5.0 3 - 3.6 600 1.7 - •Battery switchover with fixed reference,
integrated audio amplifier, I²C
M41T00Cap PCDIP24 17.8x 34.3 2.7 - 5.5 - - - •Battery switchover with fixed reference,
integrated battery, I2C, crystal
M41T11SO-8
SOH-283.9x4.9 8.2x17.8
2 - 5.5 800 2 56 - Battery switchover, SNAPHAT package available, I²C
M41T56 SO-8 3.9x4.9 4.5 - 5.5 450 2.5 56 - I²C
M41T80 SO-8 3.9x4.9 2 - 5.5 1500 2 - - Battery switchover, I²C, programmable alarm, SQW
M41T81 SO-8 3.9x4.9 2 - 5.5 600 2 - -Battery switchover, low battery detection, I²C,
programmable alarm, SQW, WDG
M41T81SSO-8
SOX-183.9x4.9 7.6x11.6
2.7 - 5.5 600 2 - •Battery switchover with fixed reference, low battery detection,
crystal, I²C, programmable alarm, SQW, WDG
M41T82 SO-8 3.9x4.9 2.38 - 5.5 365 1.8 12 •Analog calibration, battery switchover with fixed reference,
low battery detection, I²C, POR/LVD
M41T83QFN16 SOX-18
4.0x4.0 7.6x11.6
2.38 - 5.5 365 1.8 12 •Analog calibration, battery switchover with fixed reference,
low battery detection, I²C, programmable alarm, SQW @ 32 kHz, WDG, POR/LVD
M41T93QFN16 SOX-18
4.0x4.0 7.6x11.6
2.38 - 5.5 365 1.8 12 •Analog calibration, battery switchover with fixed reference,
low battery detection, crystal, 10 MHz SPI, programmable alarm, SQW @ 32 kHz, WDG, POR/LVD
M41ST85wSOH28 SOX-28
8.2x17.7 17.9x7.6
2.7 - 3.6 400 - 44 -
Battery switchover with fixed reference, low battery detection, microprocessor supervisor functions, crystal,
SNAPHAT package, I²C, programmable alarm, SQW, WDG, POR/LVD, PFI/PFO, RSTin
M41ST87wSOX-28 SSOP20
7.6x17.9 5.3x7.2
2.7 - 3.6 500 - 128 •
Battery switchover with fixed reference, low battery detection, microprocessor supervisor functions, tamper detection, I²C,
programmable alarm, SQW @ 32 kHz, WDG, POR/LVD, PFI/PFO, RSTin
M41T94SO16
SOH283.8x9.8 8.2x17.7
2.7 - 5.5 400 - 44 -
Battery switchover with fixed reference, low battery detection, microprocessor supervisor functions, snaphat package,
2 MHz SPI, programmable alarm, SQW, WDG, POR/LVD, RSTin
M41TC8025 S0-14 9.90 x 5.30 1.6 - 5.5 800 1.6 - -Temperature compensated, Low battery detection, I²C,
programmable alarm, SQW, Fout 1 Hz-1 KHz-32 KHz, POR/LVD
SEriaL rEaL-TiME CLoCkS porTfoLio
15
SnapHaT® paCkagingSerial real-time clocks are packaged in a special SNAPHAT SOIC which mates with ST’s SNAPHAT battery/crystal top. The SNAPHAT top can be removed and replaced allowing the user to extend the battery backup time indefinitely.
SnapHaT® TopS, baTTEry and CrySTaL inTEgraTEd
EMbEddEd CrySTaL paCkagingThe 32 KHz crystal is encapsulated in the serial real-time clock IC package. This allows the crystal to be less sensitive to humidity, temperature and vibration with the benefit of being a surface mount solution. It also enhances security by shielding the crystal from tampering.
48 mAh 120 mAh
M4T28-BR12SH M4T32-BR12SH
SOX28 Embedded crystal(internal view)
SOX18Embedde crystal(internal view)
gLoSSary
function description
Timekeeping supply voltage Minimum oscillator operating voltage for specified temperature range.
programmable alarmsAn alarm which can be set for a specified date and time, or to repeat at a certain day of every month, or at a certain hour of every day, or at a certain minute of every hour, or a certain second of every minute.
Square wave output (SQw) A user programmable square wave signal with rail-to-rail amplitude and 50% duty cycle which is output on the SQW pin.
oscillator fail detectA flag bit used to indicate that the oscillator has either stopped, or was stopped for some period of time and can be used to judge the validity of the clock and date data.
power-up output frequency (f32k)A special 32 kHz square wave function which is enabled on power-up to output on the F32K pin. Some devices offer this power-up default signal on the SQW pin.
battery switchover (vSo)The voltage threshold at which the device power is switched to the back-up battery supply when VCC falls. At this time the clock registers is maintained by the attached battery supply. As system power returns and VCC rises above VSO, the battery is disconnected, and the power supply is switched to external VCC.
watchdog timer (wdg)The watchdog timer is used to detect an out-of-control microprocessor. The user programs the watchdog timer by setting the desired amount of time-out into the watchdog register.
battery low detect (bL)Battery low detect is an automatic comparison of the battery voltage with a reference voltage of ~2.5 V. If the battery voltage is found to be less than 2.5 V, a flag is set and clock data should be considered suspect and verified as correct. A fresh battery should be installed.
power on reset/low voltage detector output (por/Lvd)
A continuous monitor of the VCC supply. When VCC falls to the power fail detect threshold, the /RST output pulls low and remains low for a defined recovery time after power-up,
power fail comparator (pfi/pfo) This function is intended for use as an early warning undervoltage detector to signal a failing power supply.
reset inputs (rSTin) Independent inputs which can generate an output reset which is identical to a reset generated by a power cycle.
paCkagE opTionS
LCC81.5 mm x 3.2 mmEmbedded crystal
QFN163 mm x 3 mm
QFN164 mm x 4 mm
DFN165 mm x 4 mm
SO83.80 mm x 4.80 mm
SO149.9 mm x 5.3 mmEmbedded crystal
SO163.80 mm x 9.80 mm
SSOP207.2 mm x 5.3 mm
PCDIP24 CAPHAT™34.29 mm x 17.83 mmSelf-contained battery
and crystal (internal view)
SOX1811.61 mm x 7.62 mm
Embedded crystal SOIC
SOX2818.01 mm x 7.67 mm
Embedded crystal
SOH2817.71 mm x 8.23 mm
SNAPHAT™:Battery and crystal snap on module to order separately (internal view)
© STMicroelectronics - December 2012- Printed in United Kingdom - All rights reservedThe STMicroelectronics corporate logo is a registered trademark of the STMicroelectronics group of companies
All other names are the property of their respective owners
For more information on ST products and solutions, visit www.st.com/rtcOrder code: BRRTC1212
Real-time clocks application notes, technical notes, online calculators and resources
Readers will find these documents helpful in understanding some of the subtleties of RTCs and what it takes to keep them running reliably.
Design support
application notes
an922 Using a super cap to back up the M41T56, M41T00, M41T11, M41T81, M41T94 and M41ST84W (16-pin)
an923 Timekeeper rolling into the year 2000 (21st century, Y2K)
an1011 Battery technology used in NVRAM and real-time clock (RTC) products from ST
an934 How to use the digital calibration feature in Timekeeper® and serial real-time clock (RTC) products
an1012 Predicting the battery life and data retention period of NVRAMs and serial RTCs
an1879 How to use M41ST87 tamper detect and RAM clear
an1572 Power-down time-stamp function in serial real-time clocks (RTCs)
an2583 Understanding and applying the M41T00AUD real-time clock with audio
an2678 Extremely accurate timekeeping over temperature using adaptive calibration
an2971 Using the typical temperature characteristics of 32 KHz crystal to compensate the M41T83 and the M41T93 serial real-time clocks
an3060 Applications guide for serial real-time clocks (RTCs)
Technical note
Ta0344 Highly accurate, automatic temperature-compensated real-time clock (RTC) solution
produCT SupporT aT HTTp://www.ST.CoM/rTC • Datasheets
• Application notes
• Selector tables
• Serial RTC example code
• UL information
• Clock calibration tools
• RTC and NVRAM model files
• Design support calculators @ www.st.com/calculators
• Online technical support