SLOS510E September 2006 – October 2016 TLC082-Q1 , TLC084-Q1
PRODUCTION DATA.
To achieve the levels of high performance of the TLC08x-Q1, follow proper printed-circuit board (PCB) design techniques. A general set of guidelines is given in the following.
The TLC08x-Q1 is available in a thermally-enhanced PowerPAD family of packages. These packages are constructed using a downset leadframe upon which the die is mounted [see Figure 48(a) and Figure 48(b)]. This arrangement results in the lead frame being exposed as a thermal pad on the underside of the package [see Figure 48(c)]. Because this thermal pad has direct thermal contact with the die, excellent thermal performance can be achieved by providing a good thermal path away from the thermal pad.
The PowerPAD package allows for both assembly and thermal management in one manufacturing operation. During the surface-mount solder operation (when the leads are being soldered), the thermal pad must be soldered to a copper area underneath the package. Through the use of thermal paths within this copper area, heat can be conducted away from the package into either a ground plane or other heat dissipating device.
NOTE
Soldering the thermal pad to the PCB is always required, even with applications that have low power dissipation.
This soldering provides the necessary thermal and mechanical connection between the lead frame die pad and the PCB. Although there are many ways to properly heatsink the PowerPAD package, the following steps list the recommended approach.
The thermal pad must be connected to the most-negative supply voltage (GND pin potential) of the device.
For a given RθJA, use Equation 1 to calculate the maximum power dissipation.
The next consideration is the package constraints. The two sources of heat within an amplifier are quiescent power and output power. The designer should never forget about the quiescent heat generated within the device, especially multi-amplifier devices. Because these devices have linear output stages (class A-B), most of the heat dissipation is at low-output voltages with high-output currents.
The other key factor when dealing with power dissipation is how the devices are mounted on the PCB. The PowerPAD devices are extremely useful for heat dissipation. But, the device should always be soldered to a copper plane to fully use the heat dissipation properties of the thermal pad. The SOIC package, on the other hand, is highly dependent on how it is mounted on the PCB. As more trace and copper area is placed around the device, RθJA decreases and the heat dissipation capability increases. The currents and voltages shown in Typical Characteristics are for the total package. For the dual or quad amplifier packages, the sum of the RMS output currents and voltages should be used to choose the proper package.