MTB20N20E

8

Motorola TMOS Power MOSFET Transistor Device Data

SOLDER STENCIL GUIDELINES

Prior to placing surface mount components onto a printed

circuit board, solder paste must be applied to the pads. Solder

stencils are used to screen the optimum amount. These

stencils are typically 0.008 inches thick and may be made of

brass or stainless steel. For packages such as the SC–59,

SC–70/SOT–323, SOD–123, SOT–23, SOT–143, SOT–223,

SO–8, SO–14, SO–16, and SMB/SMC diode packages, the

stencil opening should be the same as the pad size or a 1:1

registration. This is not the case with the DPAK and D2PAK

packages. If one uses a 1:1 opening to screen solder onto the

drain pad, misalignment and/or “tombstoning” may occur due

to an excess of solder. For these two packages, the opening

in the stencil for the paste should be approximately 50% of the

tab area. The opening for the leads is still a 1:1 registration.

Figure 17 shows a typical stencil for the DPAK and D2PAK

packages. The pattern of the opening in the stencil for the

drain pad is not critical as long as it allows approximately 50%

of the pad to be covered with paste.

Figure 17. Typical Stencil for DPAK and

D2PAK Packages

SOLDER PASTE

OPENINGS

STENCIL

SOLDERING PRECAUTIONS

The melting temperature of solder is higher than the rated

temperature of the device. When the entire device is heated

to a high temperature, failure to complete soldering within a

short time could result in device failure. Therefore, the

following items should always be observed in order to

minimize the thermal stress to which the devices are

subjected.

should be 100

°C or less.*

leads and the case must not exceed the maximum

temperature ratings as shown on the data sheet. When

using infrared heating with the reflow soldering method,

the difference shall be a maximum of 10

°C.

260

°C for more than 10 seconds.

temperature gradient shall be 5

°C or less.

allowed to cool naturally for at least three minutes.

Gradual cooling should be used as the use of forced

cooling will increase the temperature gradient and result

in latent failure due to mechanical stress.

cooling.

* Soldering a device without preheating can cause excessive

thermal shock and stress which can result in damage to the

device.

* Due to shadowing and the inability to set the wave height to

incorporate other surface mount components, the D2PAK is

not recommended for wave soldering.