Page 8

ADVANCED COMMUNICATIONS & SENSING

DATASHEET

SX8124

24 hours timer synchronized on 50/60Hz mains

ACS - Revision 2.4

October 2010

© Semtech Corp.

4Power Modes

4.1

Safe mode

The internal system goes in Safe mode as soon as the VDD voltage is above 0.6-0.7V. In this mode all pins are

set in high impedance and are inactive. This guarantees a safe start-up.

4.2

Low voltage mode

The internal 24h timer and phase detection/synchronization functions are active. All input ( BUTTON, PHASE,

DURATION ) pins functionalities remains active but will not activate the outputs.

All outputs are forced to a default static state as follows:

OUT pin is forced high

NOUT pin is forced low

LED pin is low

4.3

Active mode

The outputs are active and set according to the device internal states:

OUT and NOUT pin active (see “Operating” on page 10)

LED pin sending 250ms bursts (see “LED output” on page 15)

Figure 3. Operating modes vs VDD voltage

IOs ON

VDD

IOs OFF

Timer ON / OFF

Hysteresis

time

SAFE

ACTIVE

SAFE

1.05V

0.95V

0.9V

0.6V

0V

Safe

LOW

VOLTAGE

LOW

VOLTAGE