Datasheet

THERMAL CONSIDERATIONS
DFN LAYOUT GUIDELINES
DFN PACKAGE
OPA211
OPA2211
www.ti.com ...................................................................................................................................................... SBOS377G – OCTOBER 2006 – REVISED MAY 2009
most likely will not operate normally. If the supplies DFN packages are physically small, and have a
are low impedance, then the current through the smaller routing area, improved thermal performance,
steering diodes can become quite high. The current and improved electrical parasitics. Additionally, the
level depends on the ability of the input source to absence of external leads eliminates bent-lead
deliver current, and any resistance in the input path. issues.
The DFN package can be easily mounted using
standard printed circuit board (PCB) assembly
techniques. See Application Note QFN/SON PCB
A primary issue with all semiconductor devices is
Attachment (SLUA271 ) and Application Report Quad
junction temperature (T
J
). The most obvious
Flatpack No-Lead Logic Packages (SCBA017 ), both
consideration is assuring that T
J
never exceeds the
available for download at www.ti.com .
absolute maximum rating specified for the device.
However, addressing device thermal dissipation has
The exposed leadframe die pad on the bottom of
benefits beyond protecting the device from damage.
the package must be connected to V – . Soldering
Even modest increases in junction temperature can
the thermal pad improves heat dissipation and
decrease op amp performance, and
enables specified device performance.
temperature-related errors can accumulate.
Understanding the power generated by the device
within the specific application and assessing the
thermal effects on the error tolerance lead to a better
The exposed leadframe die pad on the DFN package
understanding of system performance and
should be soldered to a thermal pad on the PCB. A
thermal-dissipation needs. For dual-channel products,
mechanical drawing showing an example layout is
the worst-case power resulting from both channels
attached at the end of this data sheet. Refinements to
must be determined. Products with a thermal pad
this layout may be necessary based on assembly
(DFN and PowerPAD devices) provide the best
process requirements. Mechanical drawings located
thermal conduction away from the junction; see the
at the end of this data sheet list the physical
Thermal Resistance from Junction to Pad parameter
dimensions for the package and pad. The five holes
( θ
JP
) in the Electrical Characteristics section. The use
in the landing pattern are optional, and are intended
of packages with a thermal pad improves thermal
for use with thermal vias that connect the leadframe
dissipation. The device achieves its optimal
die pad to the heatsink area on the PCB.
performance through careful board and system
Soldering the exposed pad significantly improves
design that considers characteristics such as board
board-level reliability during temperature cycling, key
thickness, metal layers, component spacing, airflow,
push, package shear, and similar board-level tests.
and board orientation. Refer to these application
Even with applications that have low-power
notes (available for download at www.ti.com ) for
dissipation, the exposed pad must be soldered to the
additional details: SZZA017A , SCBA017 , and
PCB to provide structural integrity and long-term
SPRA953A . For unusual loads and signals, see
reliability.
SBOA022 .
The OPA211 is offered in an DFN-8 package (also
known as SON). The DFN package is a QFN
package with lead contacts on only two sides of the
bottom of the package. This leadless package
maximizes board space and enhances thermal and
electrical characteristics through an exposed pad.
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Product Folder Link(s): OPA211 OPA2211