The THS3470 package is designed for a top-side heat sink to help dissipate heat under high-power load conditions. Many types of heat sinks can be used with the device, but the THS3470REBEVM includes the FSP40-25M31-0M06 by Alpha Novatech, Inc. This is a 40 by 40mm aluminum heat sink with 25mm tall fins and included 30 by 30mm 10,000 rpm 12V fan. All heat sinks must also include a low thermal resistance interface material between the heat sink and top-side thermal pad of the THS3470. The EVM includes a standard 3-pin header J9 to connect the heat sink fan to a power supply. The supply voltage for the fan must be provided externally using test point TP12. For the included heat sink the fan power supply voltage is 12V.

When using a heat sink that is larger than the area of the THS3470 device, any additional components under the area of the heat sink must have a height less than 1mm so that the components do not interfere with the contact between the heat sink and THS3470 package. Additionally, if the heat sink is not electrically insulative, put an electrically insulative covering on the bottom of the heat sink in all areas that do not contact the THS3470. The additional insluative coating is to protect against any accidental contact with heat sink or other component causing an electrical connection to the top-side thermal pad of the THS3470, which is biased to the negative supply voltage. A simple insulative coating can be achieved using Kapton® tape to cover the bottom of the heat sink where the heat sink does not contact the THS3470.