3-WIRE INTERFACE REAL-TIME CLOCK IN A SOT PACKAGE
SUNNYVALE, CA-September 6, 2001-Maxim Integrated Products introduces the MAX6901 real-time clock (RTC) with a 3-wire interface. This product is the first 3-wire RTC to be packaged in a tiny 8-pin SOT23. Its small size and low power consumption make it ideal for portable and battery-operated systems.
The MAX6901 RTC counts seconds, minutes, hours, day, month, year, and date. The end-of-the-month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year up to 2100. The clock operates in either 24-hour or 12-hour format with an AM/PM indicator. In addition, the MAX6901 features a pollable time/date-programmable ALARM function.
This RTC uses an external watch crystal and it requires no extra crystal bias resistors or capacitors. The crystal is a standard 32.768kHz, 12.5pF load component that is readily available at low cost. In addition, the MAX6901 features a 32.768kHz output available for customer use.
Communication with the device is carried out through a 3-wire interface. This interface is used to read the time or date from the timekeeping registers, and set the time or date by writing to the timekeeping registers. The 3-wire interface is also used to configure the 24-hour/12-hour mode and the AM/PM mode. The timekeeping registers can operate in burst or single read/write mode.
An enhancement of the MAX6901 is the addition of 31 bytes x 8 bits wide of SRAM for scratchpad data storage. The SRAM can be configured to operate in burst or single read/write mode.
An ideal RTC for battery-powered systems, the MAX6901 operates from a supply voltage as low as 2.0V while consuming just 400nA timekeeping supply current. The maximum supply voltage is 5.5V and operation is over the industrial temperature range (-40°C to +85°C). The 3-wire bus interface can operate at 2MHz at 5V and 500kHz at 2V.
Prices start from $1.45 for the MAX6901 (1000-up, FOB USA).
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