40 GHz SOI Switch Beats GaAs Solutions
The UltraCMOS® PE42524 is a high performance, high reliability RF silicon on insulator (SOI) alternative to gallium arsenide (GaAs) switches covering the K- and Ka-Bands up to 40 GHz.
Until now, RF engineers developing high frequency test-and-measurement, microwave backhaul, radar and military communications devices had no viable alternative to GaAs switches. Unfortunately, these GaAs switches require compromises in performance. They are not, for example, able to maintain consistent broad frequency performance. They are not able to provide low frequency power handling while maintaining signal fidelity as the power is transferred. ESD ratings are low, while power consumption is high.
Peregrine’s PE42524 is manufactured on a patented variation of SOI technology on a sapphire substrate, which offers several key benefits that are significant to high frequency design. Sapphire has a loss tangent that is 10 times better than bulk CMOS and three times better than GaAs. As an ultra high-resistivity substrate, sapphire provides high isolation and minimizes parasitic capacitance. The sapphire substrate eliminates many substrate-coupling effects, common in silicon-based substrates, offering RF system engineers exceptional levels of linearity and power-handling performance.
Product Description and Performance
Peregrine’s UltraCMOS PE42524 is a single-pole double-throw (SPDT) RF switch die that supports a wide frequency range from 10 MHz to 40 GHz. It delivers exceptionally high port-to-port isolation, low insertion loss and excellent linearity. The switch exhibits 47 dB isolation and 2.2 dB insertion loss at 30 GHz, as well as 50 dBm IIP3 at 13.5 GHz. It also features high power handling capability, with no degradation in linearity up to its P1dB compression point of 31.5 dBm at 26.5 GHz and 28 dBm at 35 GHz (see Figure 1).
The PE42524 has a fast switching time of 225 nanoseconds, a fast settling time of 840 nanoseconds and a high ESD rating of 2000 V human body model (HBM) on all pins. In addition, the switch maintains excellent performance across temperatures from -40º to +85ºC over the entire frequency range (see Figure 2).
Unlike GaAs solutions, no blocking capacitors are required if DC voltage is not present on the RF ports. The PE42524 is available as a flip-chip die with 500 microns bump pitch, which eliminates high-frequency performance variations due to bond wire length variances.
Because the PE42524 is based on UltraCMOS technology, it features several attributes that GaAs technology cannot match:
- Broad bandwidth that maintains performance across the frequency range and over manufacturing lots
- Low frequency power handling that maintains signal fidelity as the power passes through
- Fast settling time that avoids the gate-lag phenomenon
- High linearity that ensures minimal signal compression
- High ESD rating that offers four times more protection
- Low power consumption that uses less than 50 nA of DC current
These attributes make the PE42524 ideal for test-and-measurement, microwave backhaul, radar and military communications applications.
Test and measurement equipment benefits most from the PE42524’s very constant – nearly flat – insertion loss across a wide frequency range. This performance helps equipment designers minimize any variations within the test system to ensure accurate readings for the device being tested. As with insertion loss, the power handling maintains a very steady performance across the frequency range, offering additional equipment stability. In addition, the switch delivers very broadband measurement capabilities within the test equipment, allowing it to test a wider range of devices.
Peregrine’s PE42524 is also well suited to narrowband applications, including military communications and microwave backhaul. In the case of military communications, the switch offers insertion loss that is competitive to GaAs and other offerings while delivering the best-in-class isolation performance. The frequency range covers L- through X- to Ka-Band, and the switch provides consistent power handling for 0.5 to 1.0 W applications. Peregrine’s switch also addresses the need for greater linearity with signal integrity, which facilitates getting more bits per hertz of bandwidth.
Microwave backhaul equipment is another narrowband application where the PE42524 excels. Rather than creating a different reference design for each region, due to FCC and other regulatory agency restrictions, microwave backhaul engineers now have the flexibility of using a single switch in a number of unique microwave backhaul plans in multiple geographies.
Finally, the PE42524 marks Peregrine Semiconductor’s first step in proving a high-performance RF SOI switch in the radar market. Future enhancements are planned to make this technology available to a broader range of radar applications that require an even faster switching speed. Figure 3 shows that the 90 percent to 10 percent RF fall time of the PE42524 is less than 50 ns, and the corresponding RF rise time is virtually identical.
The UltraCMOS PE42524, the first RF SOI switch to operate up to 40 GHz, offers RF engineers a high-performance, high reliability RF SOI alternative to GaAs switches in K- and Ka- Band. With high port-to-port isolation, low insertion loss, excellent linearity and high power handling capability, the PE42524 is ideal for test and measurement, microwave-backhaul, radar and military communications applications.
San Diego, Calif.