LX1701CLQ MICROSEMI [Microsemi Corporation], LX1701CLQ Datasheet - Page 16

• Manufacturer Part Number: LX1701CLQ
• Description: 2W Filterless Mono Class-D Audio Amplifier
• Manufacturer: MICROSEMI [Microsemi Corporation]

Copyright © 2004
Rev. 1.0a, 2004-07-09
PCB D
One of the key efforts in implementing the MLP package
on a pc board is the design of the land pattern. The MLP
has rectangular metallized terminals exposed on the bottom
surface of the package body. Electrical and mechanical
connection between the component and the pc board is
made by screen printing solder paste on the pc board and
reflowing the paste after placement. To guarantee reliable
solder joints it is essential to design the land pattern to the
MLP terminal pattern, exposed PAD and Thermal PAD via.
There are two basic designs for PCB land pads for the
MLP: Copper Defined style (also known as Non Solder
Mask Defined (NSMD)) and the Solder Mask Defined style
(SMD). The industry has had some debate of the merits of
both styles of land pads, and although we recommend the
Copper Defined style land pad (NSMD), both styles are
acceptable for use with the MLP package. NSMD pads are
recommended over SMD pads due to the tighter tolerance
on copper etching than solder masking. NSDM by
definition also provides a larger copper pad area and allows
the solder to anchor to the edges of the copper pads thus
providing improved solder joint reliability.
D
T
As a general rule, the PCB lead finger pad (Y) should be
designed 0.2-0.5mm longer than the package terminal
length for good filleting. The pad length should extended
0.05mm towards the centerline of the package. The pad
width (X) should be a minimum 0.05mm wider than the
package terminal width (0.025mm per side), refer to figure
5. However, the pad width is reduced to the width of the
component terminal for lead pitches below 0.65mm. This is
done to minimize the risk of solder bridging.
ERMINALS
ESIGN
Figure 5 – PC Board Land Pattern Geometry for MLP Terminals
TM
ESIGN
0.05mm
Y2
OF
G
PCB L
UIDELINES
11861 Western Avenue, Garden Grove CA. 92841 714-898-8121, FAX [phone]
AND
0.20mm
Part
Part Lead
Solder
PCB Pad
PCB
Y1
P
ATTERN
P C B D E S I G N G U I D E L I N E S
FOR
Integrated Products Division
P
(X1) Min: 0.025mm
Per side for lead
pitches > 0.65mm
®
ACKAGE
Microsemi
E
The construction of the Exposed Pad MLP enables
enhanced thermal and electrical characteristics. In order to
take full advantage of this feature the exposed pad must be
physically connected to the PCB substrate with solder.
The thermal pad (D2th) should be greater than D2 of the
MLP whenever possible, however adequate clearance (Cpl
> 0.15mm) must be met to prevent solder bridging. If this
clearance cannot be met, then D2th should be reduced in
area. The formula would be: D2TH >D2 only if D2TH <
Gmin - (2 x Cpl).
Zmin= D + aaa + 2(0.2)
(where pkg body tolerance aaa=0.15)
(where 0.2 is outer pad extension)
Gmin= D-2(Lmax)-2(0.05)
(where 0.05 is inner pad extension)
(Lmax=0.50 for this example)
D2th max = Gmin-2(CpL)
(where CpL=0.2)
2.5mm Max
XPOSED
D2th
2W Filterless Mono Class-D Audio Amplifier
P
Figure 6 – Land Pattern for LQ16 (4x4mm)
AD
P
RODUCTION
PCB D
ESIGN
D
ATA
S
HEET
2.9mm
Gmin
LX1701
4.55mm
Zmin
Page 16