SIM802 Hardware Design
Figure 18: Seiko TS621 Charge Characteristic
z
Capacitor backup
Some suitable coin cells are the coin-type capacitors available from SEIKO (XH414H-IV01E), or
from SHOEI (PAS414HR-VG1). They have a small physical size (4.8 mm diameter) and give
hours of backup time.
The specification of XH414H-IV01E is shown in following table.
Table 12: Specification of XH414H-IV01E
Parameter
Min
Type
Max
Unit
Operation temperature
-25
70
°C
Rated operation voltage
3.3
V
Charging voltage
3.3
V
Nominal capacity
( discharge capacity,3.3V to 2.0V)
0.015
mAh
Nominal capacity
( electrostatic capacity,3.3V to 0.0V)
0.07
F
Internal impedance
70
Ω
Nominal dimension (diameter)
4.8
mm
Nominal dimension (height)
1.4
mm
Note:
Gold-capacitance backup
Some suitable coin cells are the electric double layer capacitors available from Seiko (XC621),
or from Panasonic (EECEM0E204A). They have a small physical size (6.8 mm diameter) and a
nominal capacity of 0.2 F to 0.3 F, giving hours of backup time.
SIM802_HD_V2.01
12.01.2010
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