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For price, delivery, and to place orders, please contact Hittite Microwave Corporation:

20 Alpha Road, Chelmsford, MA 01824 Phone: 978-250-3343 Fax: 978-250-3373

Order On-line at www.hittite.com

Recommended SMT Attachment Technique

Preparation & Handling of the LM1 Microwave Package for Surface Mounting

The HMC LM1 package was designed to be compatible with high volume

surface mount PCB assembly processes.

The LM1 package requires a

specific mounting pattern to allow proper mechanical attachment and to

optimize electrical performance at millimeterwave frequencies. This PCB

layout pattern can be found on each LM1 product data sheet. It can also

be provided as an electronic drawing upon request from Hittite Sales &

Application Engineering.

Follow these precautions to avoid permanent damage:

Cleanliness: Observe proper handling procedures to ensure clean devices

and PCBs. LM1 devices should remain in their original packaging until

component placement to ensure no contamination or damage to RF, DC &

ground contact areas.

Static Sensitivity: Follow ESD precautions to protect against ESD strikes.

General Handling: Handle the LM1 package on the top with a vacuum collet or along the edges with a sharp pair of bent tweezers.

Avoiding damaging the RF, DC, & ground contacts on the package bottom. Do not apply excess pressure to the top of the lid.

Solder Materials & Temperature Profile: Follow the information contained in the application note. Hand soldering is not recommended.

Conductive epoxy attachment is not recommended.

Solder Paste: Solder paste should be selected based on the user’s experience and be compatible with the metallization systems

used. See the LM1 data sheet Outline drawing for pin & ground contact metallization schemes.

Solder Paste Application: Solder paste is generally applied to the PCB using either a stencil printer or dot placement. The volume of

solder paste will be dependent on PCB and component layout and should be controlled to ensure consistent mechanical & electrical

performance. Excess solder may create unwanted electrical parasitics at high frequencies.

Solder Reflow: The soldering process is usually accomplished in a reflow oven but may also use a vapor phase process. A solder

reflow profile is suggested above.

Prior to reflowing product, temperature profiles should be measured using the same mass as the actual assemblies. The thermo-

couple should be moved to various positions on the board to account for edge and corner effects and varying component masses.

The final profile should be determined by mounting the thermocouple to the PCB at the location of the device.

Follow solder paste and oven vendor’s recommendations when developing a solder reflow profile. A standard profile will have a

steady ramp up from room temperature to the pre-heat temperature to avoid damage due to thermal shock. Allow enough time

between reaching pre-heat temperature and reflow for the solvent in the paste to evaporate and the flux to completely activate.

Reflow must then occur prior to the flux being completely driven off. The duration of peak reflow temperature should not exceed

15 seconds. Packages have been qualified to withstand a peak temperature of 235°C for 15 seconds. Verify that the profile will not

expose device to temperatures in excess of 235°C.

Cleaning: A water-based flux wash may be used.

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TIME (min)

HMC441LM1

v01.0907

GaAs PHEMT MMIC MEDIUM

POWER AMPLIFIER, 7 - 15.5 GHz