ACT5880
Rev 2, 03-Sep-13
THERMAL ANALYSIS
The package thermal dissipation is not designed to
handle the total heating generated by run every
circuit at its maximum rating, which is an over-killed
situation for true applications. The sum of nominal
LDO maximum current is 2.18A and the total
DC/DC input equivalent current is 0.95A to 1.06A
for battery voltage 3.6V to 4.2V, which are 2.4W to
3.3W power dissipation respectively in the
ACT5880. Those numbers are greater than the
maximum power dissipation for the ACT5880 in FC
FBGA package, what is around 2W at 25°C.
Thermal Budget Allocation during Charging
Reference to the total current in Table 12, what is
over the possible maximum charge current of the
ACT5880. This implies that in worst case there is
no current from adaptor is allocated for charge.
Eventually, the die temperature regulation to charge
current would allocate the thermal budget to other
circuits, to the circuit desired for system operation
firstly.
Typical Operation Condition
The worst case thermal budget analysis against the
typical application is necessary. A sample case is
simultaneous video capture and transmission
operation condition. Table 12 is a reference for
thermal budget analysis with experience data.
Users should use their own data to replace those in
this table for their designs.
Table 12:
The Thermal Condition Analysis.
VOLTAGE CURRENT BUDGE
CHANNEL
LOAD BLOCK
(V)
(mA)
T
OUT1
DC/DC
Out:600
In:190
1.2
1.8
5
0.07
0.07
0.13
COREs
Memory
OUT2
DC/DC
Out:350
In:165
OUT3
DC/DC
Out:300
In:390
4.3’’ Backlight
and OTG
OUT4
OUT5
OUT6
OUT7
OUT8
OUT9
OUT10
OUT11
OUT12
OUT13
2.85
2.85
2.85
3
150
150
50
0.2
RF TxRx
RF digital
TCXO
0.2
0.07
0.24
0.26
0.15
0.04
0.06
0.36
200
150
50
I/O, ROMs
I/O, Memory
PLL
2.5
1.2
3.3
1.8
1.8
2.8
50
CODEC
25
SIM
150
80
Camera digital
0.11 Camera analog
3 OD drivers
Total
0
0
LED
1800
1.96
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