Eurotech Appliances zeus pxa270 Manuel D’Utilisation

 

© 2007 Eurotech Ltd    Issue D 

An on-board non-rechargeable coin cell battery (CR2032) provides a 3V battery 

backup supply for the ISL1208 RTC, external SRAM and the supply supervisor, when 

there is no +5V supply to the board. The ZEUS is normally shipped with battery 

disconnected. See 

, page 

, for details. 

The table below shows the typical and maximum current load on the backup battery: 

SRAM 0.3 

3 

ISL1208 RTC (with Clock Out Off) 

0.4 

0.95 

Supply Supervisor 

0.5 

0.5 

 

 

An onboard Schottky diode drops 13mV from VBAT at +25°C (+77°F). At -40°C 

(-40°F) this may increase to 170mV and at +85°C (+185°F) it may decrease 

below 10mV. The SRAM and ISL1208 minimum voltages are 1.5V and 1.8V 

respectively. Reliable operation below these minimum voltages cannot be 

guaranteed.