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HUAWEI MC509 CDMA LGA Module
Hardware Guide
Description of the Application Interfaces
Issue 01 (2011-04-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
25
Table 3-4 Coin cell characteristics
Parameter
Specifications
HB-414
ML-series
Nominal voltage
3V
3V
Nominal capacity
0.3mAh
3.4mAh
Continuous standard
load
5mA
10mA
Operating temperature
-20℃ ~ +60℃
-20℃ ~ +60℃
Diameter
4.8mm
6.8mm
Height
1.4mm
1.45mm
Weight
0.07g
0.17g
An interrupt is generated if the coin cell voltage drops too low (and the main battery is
not present). If this interrupt occurs, the RTC might be corrupted. A different interrupt
is generated if the crystal oscillator stops; this signifies that handset timing is no
longer accurate. Again, the RTC is corrupted.
When the VBAT power supply of the MC509 is normal, the coin cell charging is
powered from VBAT. The MC509 reads the coin cell voltage and monitors the
charging. During normal operation, the VCOIN pin voltage will stay above 2.2V, even
when the coin cell charger is turned off. Figure 3-2 shows the reference RTC circuit.
Figure 3-2 VCOIN interface circuit
Module
(DCE)
R
2.2k
100nF
VCOIN
Coin Cell+
-
3.3.4 Output Power Supply Interface
Output Power Supply Interface includes VCC_EXT1 PIN, VCC_EXT2 PIN and
UIM_VCC PIN.