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MCP7940MT-I/SN

MCHPMCP7940MT-I/SN

Microchip Technology
Real Time Clock (RTC) IC Clock/Calendar 64B I2C, 2-Wire Serial 8-SOIC (0.154", 3.90mm Width)
Active2,696 in stock
Datasheet Digi-Key Compare Prices

Overview

The MCP7940MT-I/SN is a low-power I2C Real-Time Clock and Calendar (RTCC) designed for timekeeping applications that require minimal energy consumption. It features digital timing compensation for crystal frequency drift and includes 64 bytes of SRAM for user data storage. The device supports clock and calendar functions with leap year compensation valid through the year 2399.

Why Choose This Part

This RTC is notable for its extremely low power consumption, drawing only 1uA during timekeeping operations. It offers dual programmable alarms and a versatile output pin that can function as a square wave generator or interrupt source. The wide operating voltage range of 1.8V to 5.5V ensures compatibility with both legacy 5V systems and modern low-voltage logic.

Applications

Battery-Powered Instrumentation
Ideal for handheld devices where the 1uA maximum timekeeping current at 5.5V extends battery life during standby.
Data Logging
Uses the 64-byte SRAM to store system configuration or event timestamps during power-down cycles.
Utility Metering
Leverages the on-chip digital trimming and calibration features to maintain accurate time across varying environmental conditions.
Consumer Appliances
Provides 12/24 hour timekeeping and dual programmable alarms for scheduled system wake-ups or user alerts.

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
Current - Timekeeping (Max) 1uA @ 5.5V

Getting Started

To evaluate this part, connect a 32.768 kHz crystal and decoupling capacitors to the oscillator pins. Communication is handled over a standard I2C interface at speeds up to 400kHz. Microchip provides the MCP794XX RTCC PICtail Plus Daughter Board for rapid prototyping with their Explorer development series.

MCP7940 Family

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

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

Also Consider

DS1307ZN+T&R Maxim Integrated - A widely used alternative that also features 56 bytes of NV SRAM but operates at a higher minimum voltage of 4.5V.

Categories

Clocks & Timing > Real-Time Clocks