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RTC battery issue

vijethahn

Jul 17, 2012
1
Joined
Jul 17, 2012
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Hi,

In a handheld device's design, we used a panasonic lithium RTC battery (BR2330) with RTC chip DS1307 as load. In additin, GPS module (LEA6H) also gets the voltage from the battery just to fix TTFF (Time to first fix).

Now following 2 issues are found. Please give your comments on these issues.

1. In some boards after assembly or after coating the PCB, the Ground point (which is trough hole) for RTC battery connection to the PCB gets disconnected from the PCB ground points. That is, no continuity was found between the RTC GND point and PCB GND point. Whether the excess temperature breaks the link between the hole for RTC GND and the GND layer?

2. In some other boards, I found that the RTC battery got discharged to 0.2V (actual voltage = 3V). The RTC chip takes current in nano amps range. RTC battery capacity 255mAh. The GPS module takes 0.024mA when the GPS is not activated. Still it can supply for atlesat 1 year. But here the battery got discharged by 1 month!

Plz give me your suggestions on these issues.

Regards,
vz
 
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