Datasheet
www.ti.com
DCGain=1
1/2
OPA2727
C
1
1nF
C
2
330pF
R
2
15.9kW
R
1
1.93kW
2.2nF
C
3
C
4
100pF
R
4
22.3kW
R
3
2.07kW
CutoffFrequency=50kHz
1/2
OPA2727
V
O
DFN PACKAGE LAYOUT GUIDELINES
OPA727 , , OPA2727
OPA4727 , OPA728
SBOS314H – SEPTEMBER 2004 – REVISED APRIL 2007
Note: FilterPro is a low-pass filter design program available for download at no cost from TI’s web site (www.ti.com ). The
program can be used to determine component values for other cutoff frequencies or filter types.
Figure 34. Four-Pole Butterworth Sallen-Key Low-Pass Filter
The OPA727 series uses the DFN-8 (also known as The leadframe die pad should be soldered to a
SON), which is a QFN package with lead contacts on thermal pad on the PCB. A mechanical data sheet
only two sides of the bottom of the package. This showing an example layout is attached at the end of
leadless, near-chip-scale package maximizes board this data sheet. Refinements to this layout may be
space and enhances thermal and electrical required based on assembly process requirements.
characteristics through an exposed pad. Mechanical drawings located at the end of this data
sheet list the physical dimensions for the package
DFN packages are physically small, have a smaller
and pad. The five holes in the landing pattern are
routing area, improved thermal performance, and
optional, and are intended for use with thermal vias
improved electrical parasitics, with a pinout scheme
that connect the leadframe die pad to the heatsink
that is consistent with other commonly-used
area on the PCB.
packages, such as SO and MSOP. Additionally, the
absence of external leads eliminates bent-lead Soldering the exposed pad significantly improves
issues. board-level reliability during temperature cycling, key
push, package shear, and similar board-level tests.
The DFN package can be easily mounted using
Even with applications that have low-power
standard printed circuit board (PCB) assembly
dissipation, the exposed pad must be soldered to the
techniques. See Application Note, QFN/SON PCB
PCB to provide structural integrity and long-term
Attachment (SLUA271 ) and Application Report,
reliability.
Quad Flatpack No-Lead Logic Packages (SCBA017 ),
both available for download at www.ti.com .
The exposed leadframe die pad on the bottom of
the package should be connected to V–.
14
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