OPA445 is a high-voltage field-effect transistor input operational amplifier 8

General power board layout guide

OPA445 provides a heat enhanced PowerPAD package. This packaging uses a bottom mounted lead frame with a mold installed on top. This arrangement exposes the lead frame underneath the package as a thermal pad. The thermal pad is in direct thermal contact with the mold; Therefore, by providing a good thermal path away from the thermal pad, excellent thermal performance can be achieved.diode

The PowerPAD package allows for simultaneous assembly and thermal management in one manufacturing operation. During the surface mount solder operation (wire bonding), the hot solder pad must be soldered to the copper area below the package. By using a thermal path within this copper region, heat can be conducted from the package to the ground layer or other heat dissipation devices. PowerPAD always needs to be soldered to the PCB, even for low-power applications. Please follow these steps:diode

1. The power board must be connected to the most negative power supply voltage V − on the device.

2. Prepare PCB with top etched pattern. Both the wire and the thermal pad should be etched.diode

3. Place recommended holes in the insulation pad area. Figure 14 shows the hot pad size and hot via pattern of the SO-8 DDA component. The diameter of these holes should be 13 mils. Keep them small so that solder core suction through the holes is not a problem during reflow soldering. The minimum recommended number of holes for SO-8 PowerPAD packaging is 5.

4. Additional through holes can be placed at any position along the thermal plane outside the thermal pad area. These through holes help dissipate the heat generated by the OPA445 integrated circuit. These additional through holes may be larger than the 13 mil diameter through-hole directly beneath the thermal pad. They can be larger because they are not in the hot pad area to be welded; Therefore, suction is not a problem.diode