BUF16821-Q1 Datasheet, PDF (28/38 Pages) Texas Instruments – Programmable Gamma-Voltage Generator

BUF16821-Q1
SBOS712 – MAY 2014
www.ti.com
Layout Guidelines (continued)
5. When connecting these holes to the internal 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 configuration makes the soldering of vias that have plane
connections easier. In this application, however, low thermal resistance is desired for the most efficient heat
transfer. Therefore, the holes under the device PowerPAD package should make their connection to the
internal plane with a complete connection around the entire circumference of the plated-through hole.
6. The top-side solder mask should leave the pins of the package and the thermal pad area with its twelve
holes exposed. The bottom-side solder mask should cover the holes of the thermal pad area. This masking
prevents solder from being pulled away from the thermal pad area during the reflow process.
7. Apply solder paste to the exposed thermal pad area and all device pins.
8. With these preparatory steps in place, simply place the device in position and run the chip through the solder
reflow operation as any standard surface-mount component. This preparation results in a properly installed
part.
For a given R_θJA (listed in the Electrical Characteristics), the maximum power dissipation is shown in Figure 26
and calculated by Equation 2:
( ) ^{P = TMAX - TA}
D
q_JA
where
• P_D = maximum power dissipation (W),
• T_MAX = absolute maximum junction temperature (125°C), and
• T_A = free-ambient air temperature (°C).
(2)
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
-40 -20
0
20
40
60
80
100
T_A, Free-Air Temperature (°C)
Figure 26. Maximum Power Dissipation
vs Free-Air Temperature
(With PowerPAD Soldered Down)
28
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