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MCP7940NT-I/SN

MCHPMCP7940NT-I/SN

Microchip Technology
Real Time Clock (RTC) IC Clock/Calendar 64B I2C, 2-Wire Serial 8-SOIC (0.154", 3.90mm Width)
Active32,168 in stock
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Overview

The MCP7940NT-I/SN is a low-power Real-Time Clock and Calendar (RTCC) from Microchip Technology featuring a 64-byte SRAM and automatic battery switchover logic. It operates over a wide voltage range of 1.8V to 5.5V and includes digital trimming for clock calibration and power-fail time-stamping to record the exact moment of a power loss event.

Why Choose This Part

The IC features on-chip digital trimming that allows for software-based clock calibration to compensate for crystal frequency drift. It simplifies system design by integrating dual programmable alarms and an automatic backup power switchover circuit that functions down to 1.3V on the backup supply.

Applications

Automotive Systems
Utilizing its AEC-Q100 qualification for dashboard clocks and vehicle telematics units.
Event Logging
Recording precise power-fail and power-restore timestamps in industrial monitoring equipment.
Smart Metering
Managing time-of-use billing and scheduled data transmissions in utility meters.
Battery-Powered Electronics
Providing ultra-low current timekeeping (1.2uA typical sleep current) for portable medical or consumer devices.

Key Specifications

Type Clock/Calendar
Features Alarm, Leap Year, Square Wave Output, SRAM
Interface I2C, 2-Wire Serial
Date Format YY-MM-DD-dd
Memory Size 64B
Time Format HH:MM:SS (12/24 hr)
Mounting Type Surface Mount
Package / Case 8-SOIC (0.154", 3.90mm Width)
Voltage - Supply 1.8V ~ 5.5V
Operating Temperature -40degC ~ 85degC
Supplier Device Package 8-SOIC
Voltage - Supply, Battery 1.3V ~ 5.5V
Current - Timekeeping (Max) 1.2uA @ 3.3V

Getting Started

Interface the device via the I2C bus (up to 400kHz) and ensure a 32.768kHz crystal is connected to the X1 and X2 pins. Engineers can use Microchip's MCP79410 RTCC PICtail Plus Daughter Board for rapid prototyping and software development.

MCP7940 Family

Comparing specs that differ across variants. The current part is highlighted.

Part Number Package Current - Timekeeping (Max) Stock
MCP7940NT-I/SN (this part) SOIC-8 1.2uA 32,168
MCP7940NT-I/MS TSSOP-8 1.2uA 22,374
MCP7940MT-I/MNY WFDFN-8 1uA 10,857
MCP7940M-I/SN SOIC-8 1uA 1,594
MCP7940MT-I/SN SOIC-8 1uA 2,696
MCP7940N-I/P DIP-8 1.2uA 1,254
Also available as: MCP7940N-I/SN, MCP7940N

Also Consider

DS1307 Analog Devices / Maxim Integrated - A widely used 5V I2C RTC alternative, though it lacks the low-voltage 1.8V operation of the MCP7940N.
DS3231 Analog Devices / Maxim Integrated - Features an integrated temperature-compensated crystal oscillator (TCXO) for much higher timing accuracy.

Categories

Clocks & Timing > Real-Time Clocks Microcontrollers > Microchip