THS6022_16 Datasheet, PDF (29/44 Pages) Texas Instruments – 250-mA DUAL DIFFERENTIAL LINE DRIVER

THS6022
www.ti.com
SLOS225D – SEPTEMBER 1998 – REVISED JULY 2007
Because of its power dissipation, proper thermal management of the THS6022 is required. Although there are
many ways to properly heatsink this device, the following steps illustrate one recommended approach for a
multilayer PCB with an internal ground plane. See Figure 58 for the following steps.
Thermal pad area = 150 mils x 170 mils (3.81 mm x 4.32 mm) with 6 vias.
Via diameter = 13 mils (0.33 mm).
M0089-01
Figure 58. PowerPAD PCB Etch and Via Pattern Minimum Requirements
1. Place six holes in the area of the thermal pad. These holes should be 13 mils (0.33 mm) in diameter.
They are kept small so that solder wicking through the holes is not a problem during reflow.
2. Additional vias may be placed anywhere along the thermal plane outside of the thermal pad area. This
will help dissipate the heat generated from the THS6022. These additional vias may be larger than the
13-mil (0.33-mm) diameter vias directly under the thermal pad. They can be larger because they are not
in the thermal-pad area to be soldered; therefore, wicking is generally not a problem.
3. Connect all holes to the internal ground plane.
4. When connecting these holes to the ground plane, do not use the typical web or spoke via connection
methodology. Web connections have a high thermal resistance connection that is useful for slowing the
heat transfer during soldering operations. This makes the soldering of vias that have plane connections
easier. However, in this application, low thermal resistance is desired for the most efficient heat transfer.
Therefore, the holes under the THS6022 package should make their connection to the internal ground
plane with a complete connection around the entire circumference of the plated-through hole.
5. The top-side solder mask should leave exposed the terminals of the package and the thermal pad area
with its six holes. The bottom-side solder mask should cover the six holes of the thermal pad area. This
prevents solder from being pulled away from the thermal pad area during the reflow process.
6. Apply solder paste to the exposed thermal pad area and all of the operational amplifier terminals.
7. With these preparatory steps in place, the THS6022 is simply placed in position and run through the
solder reflow operation as any standard surface-mount component. This results in a part that is properly
installed.
The actual thermal performance achieved with the THS6022 in its PowerPAD package depends on the
application. In the example above, if the size of the internal ground plane is approximately 3 inches × 3 inches
(7.62 mm × 7.62 mm), then the expected thermal coefficient, θ_JA, is about 37.5°C/W. For a given θ_JA, the
maximum power dissipation is shown in Figure 60 and is calculated by the following formula:
ǒ Ǔ PD +
TMAX–TA
q_JA
where:
P_D = Maximum power dissipation of THS6022 (watts)
T_MAX = Absolute maximum junction temperature (150°C)
T_A = Ambient free-air temperature (°C)
θ_JA = θ_JC + θ_CA
θ_JC = Thermal coefficient from junction to case (2.07°C/W)
θ_CA = Thermal coefficient from case to ambient air
Submit Documentation Feedback
29