Features and Benefits
- Ultra-Low-Power Extends Run Time
- 65nA Timekeeping Current
- 1.1V to 5.5V Timekeeping Voltage Range
- Automatic Switchover to Backup Supply on Power Fail Event
- Trickle Charger for External Supercapacitor or Rechargeable Battery
- Small Footprint and Low BOM
- 1.66mm x 1.26mm 12-bump WLP
- 3mm x 3mm 10-pin TDFN
- No External Load Capacitors Required
- Provides Flexibility
- Wide Range of External Crystals Supported (No External Loading Required)
- Frequency Correction with <0.5ppm Resolution
- 1.62V to 5.5V Interface Voltage Range
- Value-Added Features for Ease of Use
- Event Detection with Dedicated Pin
- Timestamps for Various Events
- Low Battery Voltage Detection
- 1/128 Second Register
- Alarms and Countdown Timer
- 32-byte User RAM
The MAX31331 ultra-low power, real-time clock (RTC) is a time-keeping device that consumes nominal 65nA timekeeping current, extending battery life. The MAX31331 supports a wide range of 32.768kHz crystals. A crystal with any capacitive loading (CL) spec can be used, which broadens the pool of usable crystals for this device. This device is accessed through an I2C serial interface.
The device also features a backup supply pin (VBAT) and automatically switches over to the backup supply (VBAT) when the main supply (VCC) drops below the programmed threshold voltage and the backup supply (VBAT) voltage.
Other features include two time-of-day alarms, interrupt outputs, programmable square-wave output, event detection input with timestamping, and a serial bus timeout mechanism. The 32-byte timestamp registers double as RAM storage. The device features a digital Schmitt trigger input (DIN) which can be used to record timestamps and/or generate an interrupt on the falling/rising edge of the DIN signal. The clock/calendar provides seconds, minutes, hours, day, month, year, and date information. A 1/128 second register is available for a sub-second timestamp resolution. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in 24-hour/12-hour format.
The MAX31331 is available in lead (Pb)-free/RoHS compliant, 12-bump, 1.66mm x 1.26mm WLP with 0.4mm pitch, as well as a 10-pin 3mm x 3mm TDFN package.
The device supports the -40°C to +85°C extended temperature range.
- Portable Instruments
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
The MAX31331 shield evaluation kit (EV kit) is a fully assembled and tested PCB to evaluate the MAX31331, an ultra-low power, low-cost, real-time clock (RTC) with I2C interface and power management. The shield operates from a single supply (either from USB or external power supply) and the onboard crystal provides a 32.768 kHz clock signal. This device is accessed through an I2C serial interface provided by a MAX32625PICO board connected to a PC by a USB port.
The MAX31331 shield EV kit provides the hardware and software graphic user interface (GUI) necessary to evaluate the MAX31331. The kit includes an installed MAX31331. It connects to the PC through a MAX32625 PICO board and a micro-USB cable.
- Portable Instruments
Documentation & Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.