2

VSS

1

VCC

2

+

8

+

6

VSS

5

VOUT-

2

VOUT-

1

VI NN

1

-

2

GND

7

VCC

2

GND

1

VCC

1

VCC

2

GND

2

GND

2

-

1

VI NP

1

-

3

VCC

4

VOUT+

1

+

2

VOUT+

1

VSS

1

VSS

2

LMP8350

SNOSB80C – FEBRUARY 2011 – REVISED OCTOBER 2015

www.ti.com

10 Layout

10.1 Layout Guidelines

While the main signal path frequencies may be fairly low, the ultra low distortion and settling time specifications

rely on wide internal bandwidths. Precautions usually taken for high-speed amplifiers should be followed to

maintain the best settling times and lowest distortion specifications. In order to get maximum benefit from the

differential circuit architecture, board layout and component selection is very critical. The circuit board should

have low a inductance ground plane and well bypassed broad supply lines. External components should be

leadless surface mount types. The feedback network and output matching resistors should be composed of short

traces and precision resistors (0.1%). The output matching resistors should be placed within 3-4 mm of the

amplifier as should the supply bypass capacitors.

The LMP8350 is sensitive to parasitic capacitances on the outputs. Ground and power plane metal should be

removed from beneath the amplifier and from beneath RF and RG.

With any differential signal path symmetry is very important. Even small amounts of asymmetry will contribute to

distortion and balance errors. Special attention should be paid to where the bypass capacitors are grounded, as

this also affects settling and distortion performance.

The LMH730154 evaluation board is an example of good layout techniques. Evaluation boards are available for

purchase through the product folder on TI’s website.

10.2 Layout Example

Figure 38. Layout Example

28

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