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PowerPAD PACKAGE

Assembly Process

ADS5542

SBAS308D – MAY 2004 – REVISED FEBRUARY 2007

Applying a RESET signal is absolutely essential to set the internal registers to their default states for normal

operation. If the hardware RESET function is not used in the system, the RESET pin must be tied to ground and

it is necessary to write the default values to the internal registers through the serial programming interface. The

following registers must be written in this order.

Write 9000h (Address 9, Data 000)

Write A000h (Address A, Data 000)

Write B000h (Address B, Data 000)

Write C000h (Address C, Data 000)

Write D000h (Address D, Data 000)

Write E000h (Address E, Data 804)

Write 0000h (Address 0, Data 000)

Write 1000h (Address 1, Data 000)

Write F000h (Address F, Data 000)

NOTE:

This procedure is only required if a RESET pulse is not provided to the device.

The PowerPAD package is a thermally enhanced standard size IC package designed to eliminate the use of

bulky heatsinks and slugs traditionally used in thermal packages. This package can be easily mounted using

standard printed circuit board (PCB) assembly techniques and can be removed and replaced using standard

repair procedures.

The PowerPAD package is designed so that the lead frame die pad (or thermal pad) is exposed on the bottom

of the IC. This provides a low thermal resistance path between the die and the exterior of the package. The

thermal pad on the bottom of the IC can then be soldered directly to the printed circuit board (PCB), using the

PCB as a heatsink.

1. Prepare the PCB top-side etch pattern including etch for the leads as well as the thermal pad as

illustrated in the Mechanical Data section. The recommended thermal pad dimension is 8 mm x 8 mm.

2. Place a 5-by-5 array of thermal vias in the thermal pad area. These holes should be 13 mils in diameter.

The small size prevents wicking of the solder through the holes.

3. It is recommended to place a small number of 25 mil diameter holes under the package, but outside the

thermal pad area to provide an additional heat path.

4. Connect all holes (both those inside and outside the thermal pad area) to an internal copper plane (such

as a ground plane).

5. Do not use the typical web or spoke via connection pattern when connecting the thermal vias to the

ground plane. The spoke pattern increases the thermal resistance to the ground plane.

6. The top-side solder mask should leave exposed the terminals of the package and the thermal pad area.

7. Cover the entire bottom side of the PowerPAD vias to prevent solder wicking.

8. Apply solder paste to the exposed thermal pad area and all of the package terminals.

For more detailed information regarding the PowerPAD package and its thermal properties, see either the

application brief SLMA004B (PowerPAD Made Easy) or technical brief SLMA002 (PowerPAD Thermally

Enhanced Package).

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