Real-time clock module has integral crystal

An Advanced Power Components (APC) product story

Edited by the Electronicstalk editorial team Jan 17, 2003

The RTC9701JE is one of the smallest real-time-clock modules designed by Epson and available now from Hero Electronics.

The RTC9701JE is one of the smallest real-time-clock modules designed by Epson and available now from Hero Electronics.

It is packed with design features including a number that optimise production efficiency.

The small 7 x 5mm package includes a 32.768kHz crystal that is already factory-trimmed to eliminate that expensive production test tweak.

The crystal stability gives a timing accuracy equivalent to one minute of monthly deviation or better; ideal for most real-time-clock applications and better than a typical desktop PC.

The clock signal is also available on an output-enabled pin.

A flexible serial interface is used, controlled by three or four pins, to reduce pin count allowing easy addition to any microprocessor or ASIC design with either a single bidirectional data pin or individual input and output pins for data transfer.

An SPI compatible microcontroller can also be used.

The RTC9701JE incorporates a nonvolatile 256 x 16bit EEPROM for user memory storage with a minimum of 100,000 program/erase cycles; ideal for storing user parameters during power-down conditions and initialisation routines.

The clock and calendar are also particularly innovative, with registers from seconds to century, all in BCD notation and with automatic adjustment for leap year to the year 2099.

The time alarm is very versatile; for example with the day of the week alarm, multiple days can be set and a dedicated interrupt pin is used for the alarm output.

A variable interval timer allows a programmable interval and duty cycle to output on another dedicated interrupt pin.

Time intervals from 1ms to 120min can be programmed.

A built-in voltage detector pin is available to monitor the main equipment battery and generate an alarm.

The RTC9701JE uses a wide-ranging supply rail of 1.8 to 5.5V and consumes only 0.8mA at 3V.

The operating temperature range is -40 to +85C.