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MCP7940N-I/SN

RTC with SRAM and EEPROM, I2C, SOIC-8

13492

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جزء الشركة المصنعة ： جزء الشركة المصنعة

MCP7940N-I/SN

الحزمة ： الحزمة

SOIC-8 (5.23 x 5.36 x 1.75 mm)

الوصف

MCP7940N-I/SN Overview

The MCP7940N-I/SN is a battery-backed I2C real-time clock from Microchip integrating 64 bytes SRAM and 128 bytes EEPROM, with only 1.2uA timekeeping current, dual alarm outputs, in an SOIC-8 package.

Key Features

I2C interface (400kHz)
Supply voltage: 1.8V-5.5V
Timekeeping current: 1.2uA
64 bytes SRAM
128 bytes EEPROM
Dual alarm function
External 32.768kHz crystal

مقدمة المنتج:MCP7940N-I/SN مقدمة المنتج

The MCP7940N-I/SN is a battery-backed I2C real-time clock/calendar (RTCC) with 64 bytes of SRAM from Microchip Technology, housed in an 8-pin SOIC package. It tracks time using internal counters for seconds, minutes, hours, days, months, years, and day-of-week with automatic leap year compensation through 2399. The device features dual programmable alarms, on-chip digital trimming with 1 PPM resolution and plus or minus 129 PPM range, and a multifunction output pin configurable as clock output, alarm output, or general-purpose output. Operating from 1.8 V to 5.5 V with I2C speeds up to 400 kHz, it achieves AEC-Q100 qualification for automotive applications.

مبدأ العمل:MCP7940N-I/SN مبدأ العمل

The MCP7940N-I/SN uses a 32.768 kHz tuning fork crystal as the timebase, divided down by internal counters to generate seconds, minutes, hours, days, months, and years. The I2C serial interface allows a host microcontroller to read and write the timekeeping registers and configure alarm functions. The digital trimming circuit adjusts the crystal oscillator frequency in 1 PPM steps by periodically adding or omitting oscillator cycles, compensating for crystal tolerance and temperature drift. When VCC drops below the switchover threshold, the power-sense circuit automatically switches to the backup battery supply (VBAT, minimum 1.3 V), ensuring continuous timekeeping and SRAM data retention. The alarm registers compare user-programmed values against the current time; upon match, the multifunction output pin asserts and the alarm flag is set in the status register. The CLKOUT pin can output programmable frequencies of 32.768 kHz, 8.192 kHz, 4.096 kHz, or 1 Hz derived from the crystal oscillator.

وصف الدبوس:MCP7940N-I/SN تعريف الدبوس ووظائفه

دبوس	الاسم	الوصف
1	X1	Crystal oscillator input; connect 32.768 kHz crystal
2	X2	Crystal oscillator output; connect 32.768 kHz crystal
3	VBAT	Battery backup input (1.3 V to 5.5 V); powers timekeeping and SRAM when VCC is absent
4	VSS	أرضي
5	SDA	I2C serial data; open-drain, requires external pull-up resistor
6	SCL	I2C serial clock; open-drain, requires external pull-up resistor
7	MFP	Multi-function output; configurable as alarm output, clock output, or general-purpose output
8	VCC	Main power supply (1.8 V to 5.5 V)

Application Scenarios:In which products and applications isMCP7940N-I/SN مستعمل

Automotive Real-Time Clock: AEC-Q100 qualified timekeeping for infotainment and body control modules
Industrial Data Logging: Timestamping events and sensor readings in battery-backed measurement systems
Embedded System Wake-Up: Alarm-triggered microcontroller wake from sleep mode for periodic tasks
Power Management: Time-stamped power-fail detection with automatic battery switchover logging
الإلكترونيات الاستهلاكية: Calendar and alarm functions in smart meters, thermostats, and appliances

Alternative Models:What chips are recommended as replacements for MCP7940N-I/SN

الطراز	الشركة المصنعة	الواجهة	SRAM	Trimming	الحزمة
MCP7940NT-I/SN	الرقاقة الدقيقة	I2C	64 B	رقمي	SOIC-8
MCP79412-I/SN	الرقاقة الدقيقة	I2C	64 B + EEPROM	رقمي	SOIC-8
DS3231SN	Maxim/ADI	I2C	236 B	TCXO	SOIC-16
PCF8563BS	NXP	I2C	0	No	TSSOP-8
RV-8803-C7	Micro Crystal	I2C	0	No	DFN-8

MCP7940N-I/SN is a battery-backed I2C RTC from Microchip in 8-SOIC with 64-byte SRAM and digital trimming. The MCP7940NT-I/SN variant includes a temperature-compensated crystal oscillator option. MCP7940M-I/SN omits the SRAM for lower cost. DS1307Z from Maxim/ADI is the industry-standard alternative RTC without battery backup. For higher accuracy, DS3231 provides ±2ppm TCXO-based RTC with integrated crystal in SOIC-16.