MAX31328NELB+

Real Time Clock Overview

The MAX31328 is a low-cost, high-accuracy I2C real-time clock (RTC) featuring an integrated temperature-compensated crystal oscillator (TCXO). It maintains timekeeping with ±3.5ppm accuracy from -40°C to +85°C. The device includes a digital temperature sensor with ±3°C accuracy and manages power via a precision comparator that switches between VCC and VBAT upon failure detection. It supports 24-hour or 12-hour formats, two programmable alarms, and a square-wave output. Operating on a single supply of +2.3V to +5.5V, it utilizes an I2C interface at up to 400kHz and is housed in a 5mm x 5mm 10-pin LGA package.

Real Time Clock Feature Summary

• Integrated TCXO provides ±3.5ppm frequency stability across the operating temperature range.
• Dual power inputs (VCC and VBAT) with automatic switchover logic for continuous operation.
• On-chip digital temperature sensor with ±3°C accuracy and aging trim register.
• Two programmable time-of-day alarms and a configurable square-wave output.

Real Time Clock Applications

• Servers
• Power Meters
• Telematics systems
• Global Positioning System (GPS) devices

Real Time Clock Procurement Notes

Verify the specific ordering suffix for the MAX31328NELB+ against the manufacturer's current datasheet revision. Confirm package availability and lead times directly with Analog Devices or authorized distributors prior to procurement planning.

Real Time Clock Selection Notes

Select this component when system design requires high timing accuracy without external crystals. Ensure the host microcontroller supports the I2C protocol. Verify that the application voltage range falls within the +2.3V to +5.5V limits for both primary and backup supplies.

Real Time Clock Part Context

This part belongs to the Maxim Integrated RTC family, designed for applications demanding precise timekeeping in space-constrained environments. The integration of the TCXO distinguishes it from standard RTCs requiring external resonators, simplifying PCB layout and improving long-term stability.

Real Time Clock Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Evaluate other Maxim Integrated RTCs with similar I2C interfaces and package types if direct replacement is required.

Real Time Clock FAQ

How does the MAX31328 handle power failures?

A precision voltage reference and comparator monitor VCC. If VCC drops below the power-fail threshold (VPF), the device automatically switches to the VBAT input to maintain timekeeping.

What is the function of the RST pin?

The RST pin serves as an active-low reset output indicating power-fail status and can also function as a debounced pushbutton input to generate a microprocessor reset signal.

Does the device support leap years?

Yes, the internal calendar automatically adjusts for months with fewer than 31 days and includes corrections for leap years up to the year 2100.