PCB Thermal Management
PCB thermal management refers to a set of techniques that designers can employ to limit the quantity of heat generated by a PCB during normal operation and to decrease the chances of excessive heat generation during abnormal operation.
Thermal management on PCBs reduces the risk of physical damage to components during normal operation and can improve the integrity of signals travelling through circuits. The more power that passes through a PCB, the more thermal management is required to keep it running smoothly. Every PCB, despite of how complex or what it’s for, should have good thermal management.
Typical applications for Thermal Management may include:
PCB Thermal Management- Via Farms & Heat Sink
- Via Farms
- Thermal vias or ‘via farms’ are tightly grouped vias that are patterned and located under heat generating devices.
- The vias can be plated with additional copper thickness (1.5 to 2.5 mils) to enhance thermal conduction of the heat from the device through the board to a secondary heatsink or chassis.
- They are the least efficient for heat removal but are cost effective for devices with low power and heat generation.
- Disadvantage – when attaching component Solder tends to flow through the vias.
- Heat Sinks
- Good thermal dissipation of small devices.
- Improved thermal heat transfer over traditional via farms. Reduced thermal resistance.
- (Ex. Thermal Vias with Rth 1.3K/W can be reduced to Rth 0.05K/W by inserting coins)
- The In-Lay opening can be tightly controlled (drilling process) resulting in good mechanical retention of the coin.
- Good planarity of the coin surface top and bottom can be maintained
- Lower cost (compared to ‘embedded coin’)
- Embedded Coins
- Similar in configuration to press fit, these copper coins are inserted during the lamination process
- The coin is retained in the coin opening by the resin of the PCB material and thus becomes an integral part of the PCB
- Can be drilled and plated as part of the of PCB
- May have ground connection (drilled holes, some thickness restrictions)
- Is bonded to the PCB through prepreg flow of coin openings
- Can be matched for required planarity on chassis side of PCB
- Coin format can vary for most application
PCB Thermal Management- Heavy Copper and PSA
- PSA(Pressure Sensitive Adhesive)
Pressure sensitive adhesive is a lower cost option for attaching pallets/coins or plate-heat sinks to a PCB where electrical conductivity is not required.
Pressure Sensitive Adhesive advantages:
- Does not require a heat source for bonding, thus simplifying the bond process.
- Relatively high Thermal resistance of tape.
- Can meet aerospace and medical requirements.
- Used in high volume in automotive applications (surface attached heatsinks)
- Heavy Copper Outer/Inner Layers
PCB Thermal Management- IMS & Heat Sink Paste
PCB Thermal Management- Embedded Bus Bar
- Increasing current as well as thermal dissipation are driving the need for copper thicker.
- When copper thickness exceeds practical etching technologies embedded busbars become practical.
- Embedded busbars take advantage of the fact tha they can pre-machined with precision prior to board fabrication.
- Once the board is fabricated the bus-bar becomes an integral part of the finished PCB
Cerra Systems is one of the leading PCB manufacturing solutions providers with PCB manufacturing plants located in North America, Asia with certifications for MIL, AS, TS, ISO, & NADCAP. Our products are Rigid, Flex, Rigid-flex, HDI, RF, and hybrid PCBs addressing up to 64 layers and 2 mil technology. Cerra Systems Major PCB Market is Aerospace, defense, Medical, computing, cellular & Industrial. PCB Manufacturer Company in India
For more information, visit- http://cerrasystems.com/