LMH6554_15 Datasheet, PDF (20/29 Pages) Texas Instruments – LMH6554 2.8-GHz Ultra Linear Fully Differential Amplifier

LMH6554
SNOSB30P – OCTOBER 2008 – REVISED JANUARY 2015
www.ti.com
10 Power Supply Recommendations
The LMH6554 can be used with any combination of positive and negative power supplies as long as the
combined supply voltage is between 4.7 V and 5.25 V. The LMH6554 will provide best performance when the
output voltage is set at the mid supply voltage, and when the total supply voltage is set to 5 V.
Power supply bypassing as shown in Power Supply Bypassing is important and power supply regulation should
be within 5% or better.
10.1 Power Supply Bypassing
The LMH6554 requires supply bypassing capacitors as shown in Figure 36 and Figure 37. The 0.01-μF and 0.1-
μF capacitors should be leadless SMT ceramic capacitors and should be no more than 3 mm from the supply
pins. These capacitors should be star routed with a dedicated ground return plane or trace for best harmonic
distortion performance. Thin traces or small vias will reduce the effectiveness of bypass capacitors. Also shown
in both figures is a capacitor from the VCM and V_EN pins to ground. These inputs are high impedance and can
provide a coupling path into the amplifier for external noise sources, possibly resulting in loss of dynamic range,
degraded CMRR, degraded balance and higher distortion.
V⁺
0.1 2F 0.01 2F
10 2F
V_CM
+IN
-IN
0.1 2F
+
-OUT
LMH6554
-
+OUT
VEN
0.1 2F
V^-
0.1 2F 0.01 2F
10 2F
Figure 36. Split Supply Bypassing Capacitors
V⁺
10 2F
0.1 2F
0.01 2F
+IN
V_CM
-IN
0.1 2F
+
-OUT
LMH6554
-
+OUT
VEN
0.01 2F
Figure 37. Single Supply Bypassing Capacitors
20
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