By definition the RF front end includes any of the components between an antenna and the baseband device. The purpose of an RF front end semiconductor is to take a baseband signal up convert it to RF for transmission by the antenna or in reverse take an RF signal and convert it to a signal the rest of the system can process. For example, in the receiver portion of a mobile phone an RF signal is the input into the front end circuitry and the output is a down converted analog signal in the intermediate (IF) frequency range. This down converted signal is the input to a baseband device, an analog-to-digital converter (ADC). For the transmit side a digital-to-analog converter (DAC) generates the signal to be up-converted, amplified and then sent to the antenna. Depending on whether the system is a WiFi, GPS or cellular radio will require different characteristics of the front end devices.
Generally RF front end devices fall into the following categories:
- RF Power Amplifiers
- RF filters and switches
- Front End modules (combination of multiple front end functions in a single module)
RF front end devices present some of the most difficult RF test challenges. In General he various types of tests for RF front end device testing include:
- DC Tests
- Power Measurement (CW)
- Power Measurement (Modulated)
- Small Signal Gain
- Servo Output Power
- Adjacent Channel Power
- Peak Detect
Test system capability lies in its ability to test Output Power, ACPR, and EVM efficiently while sourcing complex modulated waveforms. It must also have fast servos to output power and synchronized RF while allowing simultaneous current measure. Furthermore, a tester with universal RF testing ports allow for easy test hardware development and faster time to market. Finally, test system software which allows immediate test development and has the ability to change quickly for developing RF standards allow the user to focus on test results.
While front end devices present some of the toughest RF related test challenges, we are up to the challenge as evidenced by our position in the market as the dominant commercial ATE supplier for these types of devices. The reason is because testing RF front end devices is a core competency of the company and has been for some time. In the early 1980’s LTX was the first company to integrate RF instrumentation into a high volume ATE production solution. Since that time we have continued to innovate both system level RF instrumentation, as well as, test techniques that achieve very high performance RF measurement results and with a test time unmatched by competitive solutions. Add in the capability to test multiple devices in parallel and it becomes evident quickly why we are the market leader.
So what are the solutions we offer for testing RF front end devices?
Our RF test platform is the X-Series. The CX has a large installed base at OSATs throughout Asia. Our X-Series MX product was the next evolution in our RF device test solution portfolio, also has a significant installed based and incorporated the latest and greatest in RF test technology. Our latest solution for the RF front end device market is the PAx-ac. PAx-ac is also an X-Series based tester but is an application specific tester targeted specifically at RF front devices. The PAx-ac is basically the MX system with the infrastructure not required for testing RF front end devices removed. The result is a tester that still provides the latest and greatest in RF instrumentation and test techniques but at a much lower capital cost.
Some of the key features of the PAx-ac include:
- Compact footprint
- Up to 32 Universal RF Ports
- 100MHz IF bandwidth
- Large, correlated modulation library
- Coherent and low noise architecture
- Greater than 90dB Dynamic Range Optional Low Jitter Clock
- RF Source and Measure:
- Full system calibration including RF Auto Calibration kit
Learn more about the PAx-ac.