m28333-3x Mindspeed Technologies, m28333-3x Datasheet - Page 59

• Manufacturer Part Number: m28333-3x
• Description: Single/dual/triple E3/ds3/sts-1 Line Interface Unit
• Manufacturer: Mindspeed Technologies

M28331/M28332/M28333 (–3x)
Single/Dual/Triple E3/DS3/STS-1 Line Interface Unit
B.2.1 Heat Removal Path
B.2.2 Thermal Lands
Figure B-2. Package and PCB Land Configuration
28333-DSH-003-A
B
Metalization Pattern
Comp Side
A
B.2 Package Thermal Characterization
The internal heat removal path is designed to transfer heat from the top surface of
the die to the die pad and then directly to the Printed Circuit Board (PCB) through
a center solder pad. The PCB must have features designed to remove heat from
the package efficiently. At a minimum, there must be an area of solder-tinned
copper underneath the ETQFP, called a thermal land. Heat is transferred from the
thermal land to the environment through thermal vias designed within the PCB
structure.
A thermal land is required on the surface of the PCB directly under the body of
the exposed package. During normal surface mount reflow, the exposed pad on
the underside of the package will be soldered to this thermal land creating an
efficient thermal path. The size of the thermal path is as large as needed to
dissipate the required heat.
used to remove heat.
required solder mask and thermal land pattern for an EQTFP. The designer may
consider external means of heat conduction, such as attaching the copper planes
to a convenient chassis member or other hardware convection.
For double-sided PCBs having no internal layers, the surface layers must be
Mindspeed Technologies
PCB Center Pad = Body Size - 2.0 mm
Thermal Via x N,
0.33 mm Dia.
D
C
E
Figure B-2
Solder Mask
Comp Side
Appendix B: Exposed Thin Quad Flat (ETQFP) Pack
illustrates a sample package detail, including the
Via Dia. + 0.1 mm
™
Mask Opening, F sq.
B.2 Package Thermal Characterization
100998_024
B-3