803805 Bergquist, 803805 Datasheet - Page 10

• Manufacturer Part Number: 803805
• Description: STRIP LED IMS SEOUL SEMI P7
• Manufacturer: Bergquist
• Series: Thermal Clad® IMS®r
• Type: Thermal Clad Boardr

Specifications of 803805

• Shape: Square
• For Use With/related Products: Seoul Semiconductor Z-Power P7
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8
Dielectric Performance Considerations
Peel Strength
Coefficient of Thermal Expansion
This chart graphs the stability of the bond strength between the dielectric and the circuit layer
during temperature rise. Although bond strength goes down at higher temperatures, it main-
tains at least 3 lbs/inch (0.53 N/mm) even at 175°C.
ThermoMechanical Analysis (TMA) measures the dimensional stability of materials during
temperature changes, monitoring the Coefficient of Thermal Expansion (CTE). Note: In the
application, the CTE of the base material is a dominant contributor to thermal
mechanical stress. See pages 12-13 for base layer selection.
CTE OF IMS BOARDS - The concerns in exceeding T g in standard FR-4 materials from a
mechanical standpoint should be tempered when using Thermal Clad. The ceramic filler in
the polymer matrix of Thermal Clad dielectrics results in considerably lower Z-axis expansion
than in traditional FR-4 materials, while the low thickness of the dielectric means significantly
less strain on plated-through-hole (PTH) connections due to expansion.
Storage Modulus
Dielectric Stability
This chart depicts the storage modulus of the material over a temperature range. All of
our dielectrics are robust, but you will want to choose the one that best suits your operating
temperature environment. See “Assembly Recommendations” on pages 18-19 for additional
information.
Operating Thermal Clad Materials Above T g
Above the T g of the material, mechanical and electrical properties
begin to change. Mechanical changes of note are a reduction of peel
strength of the copper foil, an increase in the CTE, and decreasing
storage modulus.There is a potential benefit of relieving residual stress
on the dielectric interfaces, in solder joints and other interconnects
due to CTE mismatches by choosing a dielectric with T g below the
operating temperature. The dielectric material above T g is in its elas-
tomeric state (much lower storage modulus), allowing some of the
stresses to relax. Changes in electrical properties must also be consid-
ered in operation above T g , although they are typically only important
at frequencies above 1MHz. Effects to consider are changes in the per-
mitivity, dielectric loss and breakdown strength of the material.
Important Note: Many Thermal Clad products have U.L. rating up to
45% higher than their glass transition temperature and are used
extensively in applications above rated T g .
This charts depicts the stability of the dielectric electrical properties over a range of
temperatures. The flatter the line, the more stable. Note the stability of our high
temperature dielectric, HT to a temperature of 175°C.
Permittivity with 3" (76mm) Cu Electrode
1000 Hours at 125°C/480V
Measured at 12 Hz after