DS1340C-18#

Real Time Clock Overview

The DS1340C-18# is a real-time clock and calendar integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. It features an I2C bidirectional serial bus interface for data transfer. The device includes software clock calibration, an oscillator stop flag, and trickle-charge capability on the VBACKUP pin. It operates within a supply voltage range of 1.71V to 5.5V and supports a backup supply from 1.3V to 3.7V. The unit provides automatic power-fail detection and switching. It is housed in a 16-pin SO package with an operating temperature range of -40°C to +85°C.

Real Time Clock Feature Summary

• Integrated 16-pin SO package with built-in 32.768kHz crystal
• I2C serial interface supporting standard (100kHz) and fast (400kHz) modes
• Software clock calibration with ±10.7 seconds/month adjustment range
• Automatic power-fail detection and switching to backup supply

Real Time Clock Applications

• Portable Instruments
• Point-of-Sale Equipment
• Medical Equipment
• Telecommunications

Real Time Clock Procurement Notes

Verify the specific suffix # indicates RoHS compliance which may include lead exempt under regulations. Confirm the 16-pin SO package matches the design footprint. Ensure the 1.8V nominal voltage rating aligns with the system power bus requirements. Check for availability as distribution status varies.

Real Time Clock Selection Notes

Select this variant for designs requiring an integrated crystal to save board space. The 16-pin SO package offers a larger footprint compared to the 8-pin µSOP options. Verify that the 1.71V minimum operating voltage suits the lowest expected system rail. The trickle charger requires external resistor configuration via the control register.

Real Time Clock Part Context

This component belongs to the DS1340 family of RTCs. It is functionally equivalent to the ST M41T00 but includes enhanced features like the integrated oscillator stop flag and trickle charger. The 'C' designation specifically denotes the version with the integrated crystal, distinguishing it from the Z and U variants which require external crystals.

Real Time Clock Replacement Considerations

The DS1340C-18# is pin-compatible and functionally equivalent to the ST M41T00. Other members of the DS1340 family, such as DS1340Z-18+ or DS1340U-18+, share the same core functionality but differ in package type and crystal integration.