MOD54415 Real-Time Clock (RTC) Battery questions
Posted: Wed Mar 20, 2013 3:22 pm
I'm looking at using the RTC on the Mod54415. I've got some questions on implementing this.
1. In some applications I won't need the RTC and would rather leave the battery out because I'll be in a high ambient temp, etc.. Can I just leave the battery out and VSTBY floating or will I need to put a jumper or something to tie it to 3.3v?
2. What is the behavior when the battery dies or starts getting low? Will the varying conditions on VSTBY cause any operational issues (other than flaky RTC times)? I've seen too many products that when the standby battery goes the product stops booting properly altogether or becomes very erratic.
3. Is the current draw on VSTBY (ISTBY) in the Netburner Core Module any greater than what is published for the chip itself by Freescale? (i.e. 17uA).
4. Any recommendations on battery? I'm looking for a non-rechargable battery that will ideally have 5+ year life with a pretty reasonable price. Ideal battery would be under $5 in qty and would love to have a large enough capacity for it to get close to the rated shelf life of the battery.
Thanks!
Scott
1. In some applications I won't need the RTC and would rather leave the battery out because I'll be in a high ambient temp, etc.. Can I just leave the battery out and VSTBY floating or will I need to put a jumper or something to tie it to 3.3v?
2. What is the behavior when the battery dies or starts getting low? Will the varying conditions on VSTBY cause any operational issues (other than flaky RTC times)? I've seen too many products that when the standby battery goes the product stops booting properly altogether or becomes very erratic.
3. Is the current draw on VSTBY (ISTBY) in the Netburner Core Module any greater than what is published for the chip itself by Freescale? (i.e. 17uA).
4. Any recommendations on battery? I'm looking for a non-rechargable battery that will ideally have 5+ year life with a pretty reasonable price. Ideal battery would be under $5 in qty and would love to have a large enough capacity for it to get close to the rated shelf life of the battery.
Thanks!
Scott