Compact real-time clocks combine low power, low cost and high accuracy

2005-09-27

Download datasheet I2C (pdf) Download datasheet 3-wire (pdf) Download datasheet SPI (pdf)

DT Electronics announces a new family of real-time clocks (RTCs) from Ricoh that offer a combination of small footprint, low power, high accuracy and minimal external components. The R2023x, R2033x and R2043x are respectively I2C, 3-wire bus and SPI interface versions of the new devices, which come in a choice of TSSOP10G (4.0mm x 2.9mm x 1.0mm) or FFP12 (2.0mm x 2.0mm x 1.0mm) packages. The outputs are a 32.768kHz clock and interrupt. The devices can be software-trimmed for high timing accuracy in 1ppm steps and the extended load capacitance of up to 9pF enables a small crystal to be used, providing further space savings.

R20x3x clocks operate from 0.66V to 5.5V with a typical current consumption of just 450nA at 3V. The ability to operate at low voltages provides longer backup time or allows a smaller battery to be used. Compensation capacitors are embedded on-chip and series resistance is typically 50kOhms.

Applications are in battery-operated portable devices, home appliances, measurement equipment, set-top boxes, GPS and other communications devices.