Rainbow Electronics DS14287 User Manual

Page 22

DS14285/DS14287

22 of 25

NOTES:

1. All voltages are referenced to ground.
2. All outputs are open.
3. The MOT pin has an internal pull-down of 20 k

Ω

4. The

CEI

pin has an internal pull-up of 50 k

Ω

5. Applies to the AD0-AD7 pins, the

IRQ

pin, and the SQW pin when each is in the high impedance

state.

6. The

IRQ

pin is open drain. The interrupt and the internal clock continue to run regardless of the level

of VCC. However, it is important to insure that the pullup resistor used with the interrupt pin is never
pulled up to a value which is greater than VCC + 0.3V. As VCC falls below approximately 3.0 volts,
a power switching circuit turns the lithium energy source on to maintain the clock and timer data
functionality.

7. I

CCO

=100 mA, V

> V

BAT

8. I

CCO

=100

A, V

< V

BAT

9. Measured with a load as shown in Figure 5.
10. Expected data retention is based on using an external SRAM with a data retention current of less than

A at 25

11. Z

is an average input-to-output impedance as the input is swept from ground to V

CCI

and less than 4

mA is forced through Z

12. Real-Time Clock Modules such as the DS14287 can be successfully processed through conventional

wave-soldering techniques as long as temperature exposure to the lithium energy source contained
within does not exceed +85

C. Post-solder cleaning with water washing techniques is acceptable,

provided that ultrasonic vibration is not used.