DS1339U-33+T&R

Real Time Clock Overview

The DS1339U-33+T&R is an I2C serial real-time clock (RTC) in an 8-pin µSOP package, operating at a nominal 3.3V supply with a range of 2.97V to 5.5V. It provides seconds, minutes, hours, day, date, month, and year information with automatic leap-year compensation valid until 2100. The device features two programmable time-of-day alarms and a programmable square-wave output. A built-in power-fail detect circuit automatically switches to a backup supply (VBACKUP) to maintain timekeeping when primary power is lost. It supports standard (100kHz) and fast mode (400kHz) I2C communication.

Real Time Clock Feature Summary

• I2C Serial Interface supporting Standard (100kHz) and Fast Mode (400kHz)
• Automatic Power-Fail Detection and Switching to Backup Supply
• Two Programmable Time-of-Day Alarms with Maskable Bits
• Programmable Square-Wave Output (1Hz, 4.096kHz, 8.192kHz, 32.768kHz)
• Trickle-Charger Capability for Battery or Super Capacitor Maintenance

Real Time Clock Applications

• Handheld Devices (GPS, POS Terminals)
• Consumer Electronics (Set-Top Box, Digital Recording)
• Telecommunications Equipment (Routers, Switches, Servers)
• Medical Devices (Glucometer, Medicine Dispenser)

Real Time Clock Procurement Notes

Verify the 'T&R' suffix indicates tape-and-reel packaging upon order confirmation. Confirm the '33' designation matches the required 3.3V nominal operating voltage. Ensure the 8-pin µSOP package fits the target PCB footprint. Check that the lead-free/RoHS-compliant status meets regulatory requirements for the final assembly.

Real Time Clock Selection Notes

Select this part for applications requiring low-power RTC functionality with I2C connectivity. The 3.3V variant is suitable for systems where VCC operates between 2.97V and 5.5V. Consider the integrated oscillator stop flag for system reliability monitoring. Evaluate the trickle-charger options if battery backup maintenance is needed without external components.

Real Time Clock Part Context

This component belongs to the DS1339 family of serial real-time clocks. The 'U' suffix denotes the 8-pin µSOP surface-mount package, distinguishing it from the 16-pin SO version ('C'). The '+T&R' indicates a lead-free/RoHS-compliant device supplied in tape-and-reel format for automated assembly processes.

Real Time Clock Replacement Considerations

Direct pin-compatible replacements within the same package include other DS1339 variants such as DS1339U-3+ or DS1339U-2+, provided the supply voltage requirements align with the specific application design.