DS1392U-3+

Real Time Clock Overview

The DS1392U-3+ is a low-voltage real-time clock (RTC) and calendar from Analog Devices/Maxim Integrated, housed in a 10-pin µSOP package. It provides hundredths of a second through year information with automatic leap-year compensation valid until 2100. The device utilizes a 3-wire synchronous serial interface for data transfer. It features a temperature-compensated voltage reference that monitors VCC and automatically switches to the VBACKUP supply during power failures. Key electrical specifications include a supply voltage range of 2.97V to 5.5V, an operating temperature range of -40°C to +85°C, and support for trickle charging of backup sources.

Real Time Clock Feature Summary

• 3-Wire Synchronous Serial Interface
• Automatic Leap-Year Compensation Valid to 2100
• Power-Fail Detection and Switch Circuitry
• Separate SQW and INT Output Pins
• Trickle-Charge Capability

Real Time Clock Applications

• Hand-Held Devices
• GPS/Telematics Devices
• Embedded Time Stamping
• Medical Devices

Real Time Clock Procurement Notes

Verify the specific suffix 'U-3+' corresponds to the 2.97V–5.5V voltage range and 3-wire interface configuration. Confirm package type is µSOP-10. Check current production status as availability may vary by region. Ensure compatibility with system voltage levels and serial bus protocols before integration.

Real Time Clock Selection Notes

Select this component when a 3-wire interface is required instead of SPI or I2C. The DS1392U-3+ is suitable for applications needing separate interrupt and square-wave outputs. It supports industrial temperatures (-40°C to +85°C). Compare against DS1390/DS1394 if SPI is preferred, or DS1339 if I2C is required. Ensure backup battery voltage falls within the 1.3V to 5.5V range.

Real Time Clock Part Context

The DS1392U-3+ belongs to the DS1390–DS1394 family of low-voltage RTCs. While DS1390/DS1391/DS1394 use SPI, the DS1392 and DS1393 utilize a 3-wire interface. The 'U' indicates the µSOP package, and '3+' denotes the 3.3V nominal voltage variant (2.97V–5.5V). This model distinguishes itself by providing dedicated SQW and INT pins rather than a combined SQW/INT pin.

Real Time Clock Replacement Considerations

Publicly confirmed substitute: RTC-4574SA:B3:PURE SN (EPSON). Verify interface compatibility as the replacement uses a 3-wire serial interface but differs in pin count (14-SOP vs 10-µSOP) and voltage ranges.