
Component Location
Trace Width
www.ti.com ................................................................................................................................................................................................ SLOS562 – AUGUST 2008
Table 1. Land Pattern Dimensions
SOLDER PAD
SOLDER MASK
COPPER
STENCIL
COPPER PAD
DEFINITIONS
OPENING
THICKNESS
OPENING
THICKNESS
Nonsolder mask
275
m
375
m
275
m x 275 m Sq.
1 oz max (32
m)
125
m thick
defined (NSMD)
(0.0, –25
m)
(0.0, –25
m)
(rounded corners)
NOTES:
1. Circuit traces from NSMD defined PWB lands should be 75
m to 100 m wide in the exposed area inside
the solder mask opening. Wider trace widths reduce device stand off and impact reliability.
2. Recommended solder paste is Type 3 or Type 4.
3. Best reliability results are achieved when the PWB laminate glass transition temperature is above the
operating range of the intended application.
4. For a PWB using a Ni/Au surface finish, the gold thickness should be less 0.5
m to avoid a reduction in
thermal fatigue performance.
5. Solder mask thickness should be less than 20
m on top of the copper circuit pattern.
6. Best solder stencil performance is achieved using laser-cut stencils with electro polishing. Use of chemically
etched stencils results in inferior solder paste volume control.
7. Trace routing away from WCSP device should be balanced in X and Y directions to avoid unintentional
component movement due to solder wetting forces.
Place all the external components very close to the TPA2035D1. Placing the decoupling capacitor, CS, close to
the TPA2035D1 is important for the efficiency of the class-D amplifier. Any resistance or inductance in the trace
between the device and the capacitor can cause a loss in efficiency.
Recommended trace width at the solder balls is 75
m to 100 m to prevent solder wicking onto wider PCB
traces.
Figure 33 shows the layout of the TPA2035D1 evaluation module (EVM).
For high current pins (VDD, GND VO+, and VO-) of the TPA2035D1, use 100-m trace widths at the solder balls
and at least 500-
m PCB traces to ensure proper performance and output power for the device.
For input pins (IN–, IN+, and SHUTDOWN) of the TPA2035D1, use 75-
m to 100-m trace widths at the solder
balls. IN– and IN+ traces need to run side-by-side to maximize common-mode noise cancellation.
Copyright 2008, Texas Instruments Incorporated
13