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RTC oscillation failed (Read 1761 times)
trashbox
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RTC oscillation failed
Sep 07th, 2010, 8:22pm
 
Hi all,

The RTC circuit is attached and the measurement result shows 50% chip oscillation is failed: probing the PAD on failed chip can make it oscillate successfully.

The post/pre AC simulation shows the gain is about 24dB and the TRAN can also oscillate successfully without considering packaging(BGA) and I/O issues.

Is there any suggestion? Thanks!
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pancho_hideboo
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Re: RTC oscillation failed
Reply #1 - Sep 8th, 2010, 2:07am
 
Evaluate negative impedance of oscillator and compare it with effective resistance of crystal.

See http://www.yoketant.com.tw/yoketant/terms.htm
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