Ricoh R2221 and R2223 Series - 2 Wire I2C Interface Real Time Clock ICs
Ricoh is a manufacturer of Real Time Clock or RTC ICs since 1982 and has been a leading innovator, developing a wide range features for these devices. Using its 28 years of experience Ricoh has been able to improve the RTC current consumption from 15µA in 1982 to a low 0.18µA for its newest devices, ensuring a long battery life. Accordingly the minimum time keeping voltage has evolved from 2.2V to only 0.9V for the new R2221 and R2223. A combination of both features guarantees a long battery backup period when the application is powered off and the RTC chip is running on the backup battery.
The R2221 and R2223 include a new added ECOmode function for ultra low current consumption. This ECOmode is designed when using a specific 32768Hz crystal for the RTC oscillator with an ESR value smaller than 45k?, as a result the RTC current consumption is only 0.18µA. The ECOmode can be enabled by a hardware ECO pin (R2221) or by a software register setting (R2223).
The RTCs are equipped with Ricoh's reputed Time Trimming Function which means that clock deviation can be compensated by software settings rather than manual trimming with a trimming capacitor. The maximum remaining clock deviation will be ±0.5ppm or ±1.5ppm, depending on register settings, as a result the actual time and date is maintained at an extremely high level of accuracy. An added advantage of software trimming is that deviation compensation settings can be changed at all times, for example settings can depend on the fluctuating ambient temperature to be measured by some external circuit or based on seasonal settings. The R2221 and R2223 have one and two interrupt outputs respectively. They can be used for various alarm and periodic output signals.
Some processor ICs accept a low subclock frequency when it is running in an economic mode. to be activated. By using the external 32kHz output frequency of the RTC IC it is possible to save costs and an additional crystal on the circuit board. This output is controlled by an additional control pin for enabling the output.
The R2221 and R2223 are in both available in TSSOP10G and a new small EQFN12 package, convenient to use on high density and small circuit boards.
Ricoh Company Ltd. is a leading global manufacturer of office automation equipment. The line up includes copiers, multifunctional and other printers, fax machines, personal computers, CD-Recordable, CD-ReWritable and DVD-ReWritable drives and media, and related supplies and services as well as digital cameras and advanced electronic devices. Ricoh is rapidly building a solid presence worldwide as a provider of comprehensive document solutions that help customers streamline their business and cut operating cost. The Ricoh Group has 319 companies of which 199 outside Japan- together employing over 76,000 people.
Ricoh Europe (Netherlands) B.V. is Ricoh Company Ltd.'s regional headquarters. Located in Amstelveen, The Netherlands, it is responsible for marketing, sales and service of Ricoh's products in Europe, the Middle East and Africa. In Europe, Ricoh has three manufacturing sites: two at Ricoh UK Products Ltd. Telford, UK; GR Advanced Materials Ltd., Stirling, UK; and Ricoh Industries France S.A., Colmar, France. In addition, Ricoh Europe's European network comprises 14 sales subsidiaries and affiliates. In the fiscal year ending March 31, 2006, revenues from Ricoh's European operations totalled over € 3 billion, accounting for 22.7% of the company's global revenues. Ricoh's worldwide sales increased with 5.6% totalling over € 13.6 billion. In March 2001 Ricoh established the European Semiconductor Support Centre to support distributors and customers with their applications or other enquiries about Power Management and Real Time Clock ICs.
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