78P2351-DB/CMI Maxim Integrated Products, 78P2351-DB/CMI Datasheet - Page 2

• Manufacturer Part Number: 78P2351-DB/CMI
• Description: BOARD DEMO 78P2351 COAX CABLE
• Manufacturer: Maxim Integrated Products

Specifications of 78P2351-DB/CMI

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Design Guidelines for TERIDIAN 78P235x LIUs
HINT: If experiencing long term bit errors in a design with isolated grounds, try connecting frame and supply
grounds near the transformer with a strip of low inductance wire.
COPPER VOID
FRAME
COMPONENT
GROUND
GROUND
LIU
Figure 1. Two different ground planes
SUPPLY (VCC) PLANE
As with the component ground plane, the power plane layer should only extend to the LIU side of the transformer.
The outer edge of the power plane should be kept 10 mils short of the ground plane’s outer edge to avoid plane-
to-plane current fringing at the plane edges.
DECOUPLING
Decoupling (bypass) capacitors are used to short high frequency noise and switching transients from supply to
the ground plane. Two decades of caps are recommended, e.g. a mix of 0.1uF and 0.001uF, in order to provide
broader bypass bandwidth.
A 0603 size bypass cap, with via as close as possible to it’s pads will provide a minimal lead inductance, further
enhancing the effectiveness of the bypass. Layout the bypass caps close to the 78P235x, preferably under the
component on the bottom side. Ceramic, low ESR caps are recommended for best frequency response.
Generally X7R dielectric capacitors provide the best price/performance trade-off.
 2008 Teridian Semiconductor Corp.
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