Pumpkin UM-20, User Manual

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Specifications subject to change without notice. All dimensions in inches. © Copyright 2012 The Connor-Winfield Corporation
Application Note AN2093
Page
16
Revision P01
Date
10 May 2013
2111 Comprehensive Drive
Aurora, Illinois 60505
Phone: 630-851-4722
Fax: 630- 851- 5040
www.conwin.com
Multi-Layer Board Design / Thermal Considerations
Figure: 16-01
A small air gap should exist between the OCXO and all the
walls of the cover.
Figure: 16-02
OCXO Pad Layout w/ Top Level Copper pour.
11. To reduce unwanted thermal gains/losses,
open a window in any top level copper pours
under the device. Excessive thermal losses
may result in higher than normal current
consumption or complete device failure. See
Figure 16-03. Excessive thermal gains will
overheat the oven core causing frequency
instability. FIGURE 16-02 illustrates a how to
properly flood a top layer while creating a
“window” under the OCXO.
Figure: 16-03
12. Optionally a thermal “moat” can be created to
prevent thermal energy transfers between the
OCXO and board as seen in Figure 17-01. A
thermal moat is a routed area around the OCXO
and is very effective means to prevent losses
from the oscillator while still allowing a top layer
pour on the board to heat sink cool other
electrical components.
13. Plastic and metal covers can be used to further
reduce small temperature fluctuations in the
system by reducing variable air flow across the
device. An effective cover will should still allow
a small air gap between the OCXO and any wall
of the cover. SEE FIGURE 16-01
14. DO NOT CONNECT ANY ELECTRICAL SIGNALS
TO PINS MARKED DNC. These pins are
reserved for factory use only, and connecting or
monitoring these signals could permanently
damage the device.