TMS320C6727B, TMS320C6726B, TMS320C6722B, TMS320C6720
Floating-Point Digital Signal Processors
www.ti.com
SPRS370C–SEPTEMBER 2006–REVISED OCTOBER 2007
7 Mechanical Data
7.1 Package Thermal Resistance Characteristics
Table 7-1 and Table 7-2 provide the thermal characteristics for the recommended package types used on the TMS320C672x DSP.
Table 7-1. Thermal Characteristics for GDH/ZDH Package
NO. |
|
|
°C/W |
AIR FLOW |
|
|
(m/s) |
||
|
|
|
|
|
|
|
Two-Signal, Two-Plane, 101.5 x 114.5 x 1.6 mm , 2-oz Cu. EIA/JESD51-9 PCB |
|
|
1 |
RθJA |
Thermal Resistance Junction to Ambient |
25 |
0 |
2 |
RθJB |
Thermal Resistance Junction to Board |
14.5 |
0 |
3 |
RθJC |
Thermal Resistance Junction to Top of Case |
10 |
0 |
4 |
ΨJB |
Thermal Metric Junction to Board |
14 |
0 |
5 |
ΨJT |
Thermal Metric Junction to Top of Case |
0.39 |
0 |
Table 7-2. Thermal Characteristics for RFP Package
|
|
|
THERMAL PAD CONFIGURATION |
|
°C/W |
AIR |
|
NO. |
|
|
TOP |
BOTTOM |
VIA |
FLOW |
|
|
|
|
ARRAY |
|
(m/s) |
||
|
|
Two-Signal, Two-Plane, 76.2 x 76.2 mm PCB(1)(2)(3) |
|
|
|
||
1 |
RθJA |
Thermal Resistance Junction to Ambient |
10.6 x 10.6 mm |
10.6 x 10.6 mm |
6 x 6 |
20 |
0 |
|
|
|
7.5 x 7.5 mm |
7.5 x 7.5 mm |
5 x 5 |
22 |
0 |
2 |
ΨJP |
Thermal Metric Junction to Power Pad |
10.6 x 10.6 mm |
10.6 x 10.6 mm |
6 x 6 |
0.39 |
0 |
|
|
Double-Sided 76.2 x 76.2 mm PCB(1) (2)(4) |
|
|
|
|
|
3 |
RθJA |
Thermal Resistance Junction to Ambient |
10.6 x 10.6 mm |
10.6 x 10.6 mm |
6 x 6 |
49 |
0 |
|
|
|
10.6 x 10.6 mm |
38.1 x 38.1 mm |
6 x 6 |
27 |
0 |
|
|
|
10.6 x 10.6 mm |
57.2 x 57 mm |
6 x 6 |
22 |
0 |
|
|
|
10.6 x 10.6 mm |
76.2 x 76.2 mm |
6 x 6 |
20 |
0 |
4 |
ΨJP |
Thermal Metric Junction to Power Pad |
10.6 x 10.6 mm |
10.6 x 10.6 mm |
6 x 6 |
0.39 |
0 |
(1)PCB modeled with 2 oz/ft2 Top and Bottom Cu.
(2)Package thermal pad must be properly soldered to top layer PCB thermal pad for both thermal and electrical performance. Thermal pad is VSS.
(3)Top layer thermal pad is connected through via array to both bottom layer thermal pad and internal VSS plane.
(4)Top layer thermal pad is connected through via array to bottom layer thermal pad.
108 |
Mechanical Data |
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TMS320C6727B, TMS320C6726B, TMS320C6722B, TMS320C6720
Floating-Point Digital Signal Processors
www.ti.com
SPRS370C–SEPTEMBER 2006–REVISED OCTOBER 2007
7.2 Supplementary Information About the 144-Pin RFP PowerPAD™ Package
7.2.1Standoff Height
This section highlights a few important details about the 144-pin RFP PowerPAD™ package. Texas Instruments' PowerPAD Thermally Enhanced Package Technical Brief (literature number SLMA002) should be consulted before designing a PCB for this device.
As illustrated in Figure 7-1, the standoff height specification for this device (between 0.050 mm and 0.150 mm) is measured from the seating plane established by the three lowest package pins to the lowest point on the package body. Due to warpage, the lowest point on the package body is located in the center of the package at the exposed thermal pad.
Using this definition of standoff height provides the correct result for determining the correct solder paste thickness. According to TI's PowerPAD Thermally Enhanced Package Technical Brief (literature number SLMA002), the recommended range of solder paste thickness for this package is between 0.152 mm and 0.178 mm.
Standoff Height
Figure 7-1. Standoff Height Measurement on 144-Pin RFP Package
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Mechanical Data |
109 |