DS1341U+T&R

Real Time Clock Overview

The DS1341U+T&R is a low-current real-time clock (RTC) from Analog Devices/Maxim Integrated, housed in an 8-pin µSOP package. It operates within a voltage range of 1.8V to 5.5V and maintains timekeeping down to 1.15V with a typical current of 250nA at 3.0V. The device supports high-ESR crystals up to 100kΩ and utilizes a 6pF load capacitance crystal. It features a fast 400kHz I2C interface, two time-of-day alarms, interrupt outputs, and a programmable square-wave output. The RTC provides calendar data through 2099 with leap year compensation.

Real Time Clock Feature Summary

• Low standby current of 250nA (typical) at 3.0V
• Compatible with high-ESR crystals up to 100kΩ
• Fast-mode I2C interface supporting 400kHz clock frequency
• External clock synchronization capability via CLKIN pin

Real Time Clock Applications

• Medical devices
• Point of Sale (POS) systems
• Telematics equipment
• Portable instruments
• Portable audio devices

Real Time Clock Procurement Notes

Verify the specific ordering suffix T&R indicates tape and reel packaging. Confirm RoHS compliance status for lead-free requirements. Ensure the component matches the 8-pin µSOP physical footprint. Check that the crystal load capacitance requirement of 6pF aligns with the system design.

Real Time Clock Selection Notes

Select this model over the DS1342 variant when the application requires a 6pF crystal instead of 12.5pF. Verify that the system can accommodate the 100kΩ ESR support if using non-standard crystals. Ensure the I2C bus timeout mechanism is utilized to prevent lockup during communication errors.

Real Time Clock Part Context

This part belongs to the DS1341/DS1342 family of low-current I2C RTCs. The 'U' designation specifies the µSOP package type, while 'T&R' denotes the tape and reel shipping format. It shares functional similarities with the DS1342 but differs in required crystal load capacitance.

Real Time Clock Replacement Considerations

The DS1342U+T&R is a direct functional substitute if the system crystal load capacitance is adjusted from 6pF to 12.5pF. Other I2C RTCs may require significant circuit redesign due to differing interface or power specifications.

Real Time Clock FAQ

What is the maximum crystal ESR supported by the DS1341?

The DS1341 supports crystals with an Equivalent Series Resistance (ESR) of up to 100kΩ.

How does the device handle external clock synchronization?

It accepts an external clock reference on the CLKIN pin. If enabled, the RTC locks to this source; if the signal is lost or deviates by more than ±0.8%, it switches back to the internal crystal oscillator.

What is the minimum voltage for timekeeping operation?

Timekeeping is maintained down to a typical voltage of 1.15V, with full operation guaranteed between 1.8V and 5.5V.