Five points let you quickly understand the RF radio frequency chip test socket

“The conventional pin of the RF radio frequency test socket still uses the corresponding pogo pin probe, but because the radio frequency transmission signal requires a special medium, the corresponding connector part is also very special. Our more common radio frequency coaxial connector (RF COAXIAL CONNECTOR ) Is one of them. This component will be embedded in the test socket for radio frequency conduction during testing.

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1. Definition of RF test socket

The RF radio frequency test socket is composed of several parts, the first is the test socket shell + the test socket conventional probe + RF radio frequency coaxial connector.

The RF test socket picture comes from the Internet

In the RF test socket, most of the structure is similar to the ordinary test socket, except for the coaxial connector.

Regarding the part of the test seat, the design ideas have also been discussed before.

Now mainly talk about RF connectors.

The RF connector is the radio frequency coaxial connector, which mainly plays the role of communication radio frequency. Through the joint efforts of the global communications industry, the RF connector has formed a professional system and international standards, and it is also an indispensable part of the connector.

2. The working principle of the RF test socket

The conventional pin of the RF radio frequency test socket still uses the corresponding pogo pin probe, but because the radio frequency transmission signal requires a special medium, the corresponding connector part is also very special. Our more common radio frequency coaxial connector (RF COAXIAL CONNECTOR ) Is one of them. This component will be embedded in the test socket for radio frequency conduction during testing.

Corresponding to the design selection of the RF connector in the corresponding test socket, you can refer to the following (not limited to the following interfaces). At the same time, when customizing the test socket, you also need to propose the insertion loss and return loss requirements of your own chip to the supplier (ie S12/S21 And S11), but also need to put forward their own contact impedance requirements:

BNC is a bayonet type, which is mostly used for radio frequency connections below 4GHz, and is widely used for instrumentation and computer interconnection.

TNC is a threaded connection, similar in size and other aspects to BNC, the working frequency can reach 11GHz, and the threaded type is suitable for vibration environments.

SMA is a threaded connection and is the most widely used. There are two impedances of 50 and 75 ohms. When 50 ohms are used, the frequency of use of flexible cables is lower than 12.4Ghz, and the maximum frequency of semi-rigid cables is 26.5GHz.

SMB is smaller in size than SMA. It is inserted into a self-locking structure and is used for fast connection. It is often used for digital communication. It is a replacement of L9, 50 ohms can reach 4GHz, and 75 ohms can reach 2GHz.

SMC is a threaded connection. Others are similar to SMB, with a wider frequency range, and are often used in military or high-vibration environments.

The N-type connector is a threaded type, uses air as an insulating material, has a low cost, and has a frequency of up to 11GHz. It is often used in testing instruments and has two types of 50 and 75 ohms.

MCX and MMCX connectors are small in size and are used for dense connections.

BMA is used for blind plug connection of low-power microwave systems with frequencies up to 18 GHz.

RF test pictures, pictures from the Internet

3. Application of RF test socket

With the current upgrade of high-speed communication standards such as 5G and WIFI6, new RF chips are widely used in mobile phones, tablets and other mobile devices, communication base stations and other communication platforms. The demand for RF test sockets is increasing and higher. At present, the main RF chips will use aging test, functional test, and special tests under extreme environments. Therefore, RF test sockets are also proposed. High testing requirements.

Fourth, the production method of RF radio frequency test socket:

Product design needs to rely on data, including chip size (length, width and thickness), chip spacing, chip shape, the frequency at which the chip needs to operate in the chip test, and the corresponding insertion loss, return loss and other data. Some RF chips have high power and may need to provide over-current requirements. As we all know, the over-current capability of the pogo pin of the test socket is less than 1A, so the over-current capability of the power pin of the chip also needs to be considered, otherwise it will affect the firepower of the chip. Open the test data.

Namely Socket + RF coaxial connector (Isolation also needs to be considered)

5. Maintenance of RF test socket:

The RF test socket needs regular maintenance. It is best to check the contact probe or RF connector with a microscope every 5000 times. Check whether there is dirt on the top of the needle and the wear of the needle to ensure that the test socket is always in good condition. Test status. If there is dirt, it is recommended to use ultrasonic cleaning equipment, put in high-purity alcohol for ultrasonic cleaning, and then use an air gun to do the final cleaning to ensure that the test seat is in a dry state, to ensure the service life and test performance of the product. If there is slight abrasion, it will not affect the test (that is, the test data does not have a big error), and you can continue to use it after cleaning. If the damage is serious, you need to replace the probe and the RF connector before you can continue to use it.