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When it comes to monolithically integrating functionality, a new benchmark has been set by M/A-COM Tech Asia with the introduction of an X-band, 8.5 to 11 GHz GaAs MMIC core chip for transmit/receive (T/R) modules. This multi-function chip, the XZ1002-BD, consists of fully integrated transmit/receive switches, a low noise amplifier (LNA), a 6-bit phase shifter, a 5-bit attenuator and an output driver amplifier. The core chip also integrates CMOS-compatible digital control circuitry and compensated on-chip gate bias.
Figure 1 XZ1002-BD block diagram.
The block diagram of the highly integrated XZ1002-BD shows the functionality of the device (see Figure 1). The core chip can be operated in either transmit or receive mode by means of the digital control circuit; this circuit also controls the phase and attenuation states in either mode.
Figure 2 Measured large signal performance sample (Ta = 35°C).
Figure 3 Attenuator performance in receive mode (Ta = 35°C).
The XZ1002-BD delivers high performance across a broad spectrum of parameters. In receive mode, the XZ1002-BD achieves 5.2 dB noise figure, 21 dB gain and +28 dBm OIP3. In transmit mode, the chip has a gain of 22 dB and +23 dBm Psat, with excellent input and output match (see Figure 2). The 5-bit attenuator in receive mode achieves 28.5 dB attenuation in 32 states. At 10 GHz, the RMS amplitude error of the attenuator is 0.3 dB (see Figure 3); the RMS phase error of the phase shifter is 1.5 degrees (see Figure 4). The 6-bit phase shifter achieves 360 degree range in 64 states.
Figure 4 Phase shifter performance in receive mode (Ta = 35°C).
Figure 5 X-band chipset for complete T/R module.
This highly integrated, unique core chip provides a high degree of functionality and greatly simplifies the design task for transmit and receive modules (see Figure 5), offering many features and benefits for users. The major benefits of this technology include a simpler design, fewer components, smaller board space, lower cost, higher reliability and better control performance.
The XZ1002-BD core chip combines up to 10 functions on one device and makes a three-chip phased-array radar T/R module a reality when matched with the XP1006 10 W power amplifier and the best-in-class XL5017 LNA. With these three devices, active X-band phased array and T/R module manufacturers can add an accurate, fast and inexpensive solution to their toolkit.
For additional T/R module options, M/A-COM Tech Asia is also developing a high power amplifier, the XP5006-BD, with power added efficiency (PAE) of 40 percent. Circulators and limiters from M/A-COM Technology Solutions are available to complete the system design if needed. In order to ease and speed up development time, a digitally controlled evaluation board for this core chip is available. The evaluation board can run on a PC with a USB connection.
The XZ1002-BD is designed for applications operating in the 8.5 to 11 GHz range and is well suited for both military and weather phased-array radar applications and satellite communications systems. The integrated on-chip bias greatly simplifies bias circuitry and overall board complexity, making the design engineer's task much simpler. Furthermore, the careful balance of performance between the 6-bit phase shifter and 5-bit attenuator enables optimized system level performance without increasing the digital processing complexity.
M/A-COM Tech Asia performs 100 percent on-wafer RF, DC and output power testing on the XZ1002-BD, as well as 100 percent visual inspection to MIL-STD-883 method 2010. The chip has surface passivation to protect and provide a rugged part with backside via holes and gold metallization to allow either a conductive epoxy or eutectic solder die attach process.
In summary, M/A-COM Tech Asia's highly integrated core chip, the XZ1002-BD, provides a high degree of functionality and greatly simplifies the design task for T/R modules. The core chip integrates a phase shifter, attenuator, transmit/receive switches, an LNA, a medium power amplifier, digital logic control and on-chip bias circuitry all onto a single GaAs MMIC. The major benefits of this technology include a simpler design, fewer components, smaller board space, lower cost, higher reliability and better control performance. In addition to the X-band XZ1002-BD core chip, M/A-COM Tech Asia offers an S-band chip, the XZ1001-BD. These core chips are ideally suited for phased-array radar applications.
M/A-COM Tech Asia,
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