M41ST87Y_10 Datasheet, PDF (1/52 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

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
■ 5.0, 3.3, or 3.0 V operation
■ 400 kHz I²C bus
■ NVRAM supervisor to non-volatize external
LPSRAM
■ 2.5 to 5.5 V oscillator operating voltage
■ Automatic switchover and deselect circuitry
■ Choice of power-fail deselect voltages
– M41ST87Y:
THS = 1: V_PFD≈ 4.63 V; V_CC = 4.75 to 5.5 V
THS = 0: V_PFD≈ 4.37 V; V_CC = 4.5 to 5.5 V
– M41ST87W:
THS = 1: V_PFD ≈ 2.9 V; V_CC = 3.0 to 3.6 V
THS = 0: V_PFD ≈ 2.63 V; V_CC = 2.7 to 3.6 V
■ Two independent power-fail comparators
(1.25 V reference)
■ Counters for tenths/hundredths of seconds,
seconds, minutes, hours, day, date, month,
year, and century
■ 128 bytes of clearable, general purpose
NVRAM
■ Programmable alarm and interrupt function
(valid even during battery backup mode)
■ Programmable watchdog timer
■ Unique electronic serial number (8-byte)
■ 32 kHz frequency output available upon power-
on
■ Microprocessor power-on reset output
■ Battery low flag
■ Ultra-low battery supply current of 500 nA (typ)
Embedded crystal
28-pin, (300 mil)
SOX28 (MX)
SSOP20 (SS)
Security features
■ Tamper indication circuits with timestamp and
RAM clear
■ LPSRAM clear function (TP_CLR)
■ Packaging includes a 28-lead, embedded
crystal SOIC and a 20-lead SSOP
■ Oscillator stop detection
April 2010
Doc ID 9497 Rev 8
1/52
www.st.com
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