PTD08D210W Datasheet, PDF (9/19 Pages) Texas Instruments – DUAL 10-A OUTPUTS, 4.75-V to 14-V INPUT, NON-ISOLATED, DIGITAL POWERTRAIN™ MODULE

PTD08D210W
www.ti.com
SLTS295B – DECEMBER 2009 – REVISED DECEMBER 2010
APPLICATION INFORMATION
Determining the Safe Operating Area
3.0
V_I = 12 V
f_SW = 750 kHz
2.5
2.0
V_O = 1.8 V
V = 2.5 V
O
1.5
V_O = 3.3 V
1.0
V_O = 1.2 V
0.5
V_O = 0.8 V
0
0
2
4
6
8
10
I_O – Output Current – A
90
400 LFM
80
70
60
200 LFM
50
100 LFM
40
Natural Convection
The Safe Operating Area (SOA) curves for the
PTD08D210W are determined by the total power
dissipation of the module, the maximum ambient
temperature, and the minimum available airflow of the
application. Operation below the application airflow
curve is considered a thermally safe design. For a
given SOA, refer to the Power Dissipation curves for
the same input voltage and switching frequency to
determine each output's power dissipation. Add the
power dissipation of V_OA and V_OB to get the total power
dissipation. The total power dissipation can then be
used to determine the safe operating area for the
application.
For example, consider an application operating from a
12-V input and a 750-kHz switching frequency,
requiring 1.2 V @ 10 A and 3.3 V @ 6 A outputs. In
order to determine the safe operating area the power
dissipation for each of the outputs must first be
determined. Using the V_I = 12 V, f_SW = 750 kHz Power
Dissipation graph, the power dissipation for the 1.2 V
@ 10 A output is 2 W and the power dissipation for the
3.3 V @ 6 A output is 1.5 W. Adding the power
dissipation for both outputs results in a total power
dissipation of 3.5 W. The safe operating area can then
be determined using the V_I = 12V, f_SW = 750 kHz SOA
graph, the amount of airflow of the application and the
3.5-W total power dissipation. At 3.5 W and 400 LFM,
the application can operate up to 85°C, but when no
airflow is available the maximum ambient temperature
is limited to less than 71°C.
30
P
+P
D(VOA) D(VOB)
20
0
1
2
V = 12 V
I
f_SW = 750 kHz
3 3.5 4
5
P – Total Power Dissipation – W
D
NOTE
• Graphs above have been replicated from the Typical Characteristics section for this example
• The maximum output current for either output must not exceed 10 A.
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