LMH6554

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SNOSB30P – OCTOBER 2008 – REVISED JANUARY 2015

11 Layout

11.1 Layout Guidelines

The LMH6554 is a high speed, high performance amplifier. In order to get maximum benefit from the differential

circuit architecture board layout and component selection is very critical. The circuit board should have a low

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 or 4 mm of the amplifier as

should the supply bypass capacitors. Refer to Power Supply Bypassing for recommendations on bypass circuit

layout. Evaluation boards are available through the product folder on ti.com.

By design, the LMH6554 is relatively insensitive to parasitic capacitance at its inputs. Nonetheless, ground and

power plane metal should be removed from beneath the amplifier and from beneath RF and RG for best

performance at high frequency.

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

distortion and balance errors.

11.2 Layout Example

Figure 38. Layout Schematic

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