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M41ST87W_11 Datasheet, PDF (1/54 Pages) STMicroelectronics – 5.0 V and 3.3/3.0 V secure serial RTC and NVRAM supervisor with tamper detection and 128 bytes of clearable NVRAM | |||
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M41ST87Y
M41ST87W
5.0 V and 3.3/3.0 V secure serial RTC and NVRAM supervisor
with tamper detection and 128 bytes of clearable NVRAM
Features
â 5.0, 3.3, or 3.0 V operation
â 400 kHz I2C bus
â NVRAM supervisor to non-volatize external
LPSRAM
â 2.5 to 5.5 V oscillator operating voltage
â Automatic switchover and deselect circuitry
â Choice of power-fail deselect voltages
â M41ST87Y:
(not recommended for new design, contact
ST sales office for availability)
THS = 1: VPFDâ 4.63 V; VCC = 4.75 to 5.5 V
THS = 0: VPFDâ 4.37 V; VCC = 4.5 to 5.5 V
â M41ST87W:
THS = 1: VPFD â 2.9 V; VCC = 3.0 to 3.6 V
THS = 0: VPFD â 2.63 V; VCC = 2.7 to 3.6 V
â Two independent power-fail comparators
(1.25 V reference)
â Counters for tenths/hundredths of seconds,
seconds, minutes, hours, day, date, month,
year, and century
â 128 bytes of clearable, general purpose
NVRAM
â Programmable alarm and interrupt function
(valid even during battery backup mode)
â Programmable watchdog timer
â Unique electronic serial number (8-byte)
â 32 kHz frequency output available upon power-
on
â Microprocessor power-on reset output
â Battery low flag
â Ultra-low battery supply current of 500 nA (typ)
Embedded crystal
28-pin, (300 mil)
SOX28
SSOP20
Security features
â Tamper indication circuits with timestamp and
RAM clear
â LPSRAM clear function (TPCLR)
â Packaging includes a 28-lead, embedded
crystal SOIC and a 20-lead SSOP
â Oscillator stop detection
October 2011
Doc ID 9497 Rev 10
1/54
www.st.com
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