LMH0384 Datasheet, PDF (21/29 Pages) National Semiconductor (TI) – 3 Gbps HD/SD SDI Extended Reach and Configurable Adaptive Cable Equalizer

www.ti.com
LMH0384
SNLS308G – APRIL 2009 – REVISED JUNE 2015
9 Power Supply Recommendations
Follow these general guidelines when designing the power supply:
1. The power supply should be designed to provide the recommended operating conditions in terms of DC
voltage, and maximum current consumption.
2. The maximum current draw for the LMH0384 is provided in the data sheet. This figure can be used to
calculate the maximum current the supply must provide. Current consumption can be derived from the typical
power consumption specification in the data sheet.
3. The LMH0384 does not require any special power supply filtering, provided the recommended operating
conditions are met. Only standard supply decoupling is required.
10 Layout
10.1 Layout Guidelines
For information on layout and soldering of the WQFN package, please refer to the following application note: AN-
1187 Leadless Leadframe Package (LLP) (SNOA401).
The ST 424, 292, and 259 standards have stringent requirements for the input return loss of receivers, which
essentially specify how closely the input must resemble a 75-Ω network. Any non-idealities in the network
between the BNC and the equalizer will degrade the input return loss. Take care to minimize impedance
discontinuities between the BNC and the equalizer to ensure that the characteristic impedance of this trace is 75
Ω.
Please consider the following PCB recommendations:
• Use surface-mount components, and use the smallest components available. In addition, use the smallest
size component pads.
• Select trace widths that minimize the impedance mismatch between the BNC and the equalizer.
• Select a board stack up that supports both 75-Ω single-ended traces and 100-Ω loosely-coupled differential
traces.
• Place return loss components closest to the equalizer input pins.
• Maintain symmetry on the complementary signals.
• Route 100-Ω traces uniformly (keep trace widths and trace spacing uniform along the trace).
• Avoid sharp bends in the signal path; use 45° or radial bends.
• Place bypass capacitors close to each power pin, and use the shortest path to connect equalizer power and
ground pins to the respective power or ground planes.
Copyright © 2009–2015, Texas Instruments Incorporated
Product Folder Links: LMH0384
Submit Documentation Feedback
21