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HUAWEI MC509 CDMA LGA Module |
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Hardware Guide | Description of the Application Interfaces |
For detailed information about power supply design and printed circuit board (PCB) design, see the HUAWEI Module Power Supply Design Guide and the HUAWEI LGA Module PCB Interconnection Design Guide
3.3.3 VCOIN Interface
VCOIN pin of MC509 module is used as backup power from the 3 V coin cell for SMPL, RTC, and 32 kHz crystal oscillator backup; a capacitor (rather than a coin cell) can be used if only SMPL is supported. Used as an analog output for coin cell or capacitor charging.
Sudden momentary power loss
If the monitored VBAT drops
Table
SMPL timer setting | Capacitor value | Capacitor package |
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0.5 sec | 1.5μF | 0805 |
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1.0 sec | 3.3μF | 0805 |
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1.5 sec | 4.7μF | 0805 |
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2.0 sec | 6.8μF | 1206 |
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If the SMPL counter expires without VBAT returning to its valid range, the MC509 must undergo the normal
Real-time clock
If RTC is used, a
Issue 01 | Huawei Proprietary and Confidential | 24 | |
Copyright © Huawei Technologies Co., Ltd. | |||
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