LMH6552 Datasheet, PDF (27/38 Pages) Texas Instruments – 1.5-GHz Fully Differential Amplifier

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Power Supply Bypassing (continued)
10 2F
V⁺
0.1 2F
LMH6552
SNOSAX9I – APRIL 2007 – REVISED JANUARY 2015
+
V_CM
-
0.1 2F
0.01 2F
ENABLE
0.1 2F
10 2F
V^-
0.1 2F
Figure 53. Split Supply Bypassing Capacitors
10 2F
V⁺
0.1 2F
0.01 2F
V_CM
0.1 2F
+
-
ENABLE
0.01 2F
Figure 54. Single Supply Bypassing Capacitors
11 Layout
11.1 Layout Guidelines
The LMH6552 is a very 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 free of charge through the product folder on ti.com.
By design, the LMH6552 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 R_F and R_G 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.
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