HUAWEI MU509-65 HSDPA LGA Module
Hardware Guide
Description of the Application Interfaces
Issue 01 (2016-04-08)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
24
Table 3-3
Coin cell characteristics
Parameter
Specifications
HB-414
ML-series
Nominal voltage
3 V
3 V
Nominal capacity
0.3 mAh
3.4 mAh
Continuous standard
load
5 mA
10 mA
Operating temperature
–20°C to +60°C
–20°C to +60°C
Diameter
4.8 mm
6.8 mm
Height
1.4 mm
1.45 mm
Weight
0.07 g
0.17 g
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 MU509-65 is normal, the coin cell is charged
from VBAT. The MU509-65 reads the coin cell voltage and monitors the charging.
During normal operation, the VCOIN pin voltage will stay above 2.2 V, even when the
coin cell charger is turned off. Figure 3-4 shows the reference RTC circuit.
Figure 3-4
VCOIN interface circuit
3.3.3 Output Power Supply Interface
Output power supply interface includes VCC_EXT1, VCC_EXT2 and USIM_VCC.
Table 3-4
Output power supply interfaces
Pin Name
Typ. (V)
Typ. (mA)
VCC_EXT1
1.8
20
