Dual-Band PADs for Next-Gen Mobile Devices
As next-generation mobile devices evolve, designers of smartphones, tablets and other handheld wireless products face daunting challenges. The seemingly insatiable demand for anytime, anywhere connectivity and high-speed data communications is driving a dramatic increase in front-end radio content. As new LTE networks deploy, many next-generation smart phones will contain up to 14 frequency bands for quad-band 2G roaming, quad-band 3G voice & data, dual- or tri-band 4G data, dual-band Wi-Fi, receive diversity, Bluetooth, GPS and FM radio. How do design engineers squeeze more RF content into small handheld devices without sacrificing performance and battery life?
Two PADs Replace 24 Discretes for Quad-Band Optimization
To help them accomplish this feat, TriQuint leverages its broad technology portfolio and integration expertise to combine active and passive components into compact modules, shrinking the precious PCB real estate occupied by RF components. To address the interference issues that arise with more radios, the modules match efficient power amplifiers (PA) with advanced filter technology to achieve lower insertion loss with higher noise rejection.
These small yet powerful integrated solutions deliver compelling advantages over discrete parts. An integrated power amplifier-duplexer module (PAD) or transmit module (TXM) can replace a handful of discrete parts with a far smaller footprint, while delivering greater efficiency, lower power consumption and better value.
Mobile device manufacturers have embraced these streamlined, high-performance solutions, and the combined PAD TXM architecture has become the chosen solution for some wireless communications designs. During the past three years alone, TriQuint shipped more than half a billion PADs and nearly 150 million TXMs. This trend toward integration is expected to continue as new LTE networks drive band count even higher.
Driving RF Integration
Taking integration to new levels, TriQuint recently introduced what is reported to be the industry's first family of dual-band PADs for next-generation 3G and 4G smartphones, tablets and other mobile devices. The ultra-small TRITIUM Duo modules combine two high-performance PADs in the space of one. At 6 × 4.5 mm, TriQuint's new dual-band modules fit into a slightly smaller space than a standard single-band PAD of 7 × 4 mm (i.e., 27 mm2 compared to 28 mm2).
The industry's first 2-in-1 PADs integrate two band-specific power amplifiers and duplexers, voltage regulation circuits and an RF output detector — replacing up to 12 discrete components. A quad-band solution with two TRITIUM Duos is about 50 mm2, half the footprint of a comparable discrete solution as shown in Figure 1. By reducing design and assembly complexity, the modules speed time-to-market, a critical factor for mobile device manufacturers as product lifecycles become ever shorter in today's highly competitive global market. A lower BOM also can produce significant savings in inventory, qualification and manufacturing.
The 2-in-1 TRITIUM Duo modules optimize the PA and duplexer match to deliver greater overall system efficiency, optimal RF front-end performance and longer battery life. Unlike discrete parts, TriQuint's dual-band PADs do not need to match circuits between the interstage filter and power amplifier, or between the amplifier output and the duplexer input. This removes production variations that can result from the need to manually match discrete components on a phone board for every band and vendor combination.
The TRITIUM Duo's PAs are mated to the duplexers using only a single-section matching network, reducing loss by 1 dB and current consumption by 20 percent. For battery-powered devices, this is a significant benefit. In addition, the balanced Rx outputs make these modules ideal for use with the latest RF transceivers without the need for an external balun.
Mix-and-Match Bands for Design Flexibility
TriQuint's TRITIUM Duo product family includes three distinct modules, each integrating two commonly used bands in one small footprint, as shown in Table 1. The band pairs offered in the three products provide global coverage for regional variations across mobile device platforms. Designers can combine the integrated 2-in-1 TRITIUM Duo PADs to add or remove bands as needed to meet the needs of a specific wireless carrier.
The dual-band modules provide a scalable, mix-and-match solution. All three TRITIUM Duo modules share a common 6 × 4.5 mm size, giving designers the flexibility to use a similar, ultra-small footprint to support multi-band, multi-mode operations across multiple mobile product platforms. Mobile device manufacturers can capitalize on the dramatic size reductions to include more features or larger batteries in thinner, lighter form factors with all the performance needed for CDMA, 3G and 4G networks.
Paired with TriQuint's QUANTUM Tx™ family of transmit modules, the dual-band PADs form a complete RF front-end solution for multi-band, multi-mode smartphones and other mobile devices (see Figure 2). Using its integration expertise to reduce PCB space requirements even further, TriQuint recently introduced two new QUANTUM Tx transmit modules that are 40 percent smaller than the previous generation, enabling more PCB layout flexibility.
Dual-Band PAD Benefits
TriQuint's TRITIUM Duo family provides several key benefits to mobile device vendors:
Smallest Size, Highly Integrated
- Two PAs and two duplexers in a module smaller than a single-band PAD
- A quad-band solution (two TRITIUM Duos) is ~ 50 mm2, half the footprint of a comparable discrete solution
- Common family footprint simplifies design, speeds overall time to market
- Mix & match popular band combinations across platforms
Lower Parts Count
- Replace up to 12 discrete parts with 1 PAD
- Reduce BOMs: improve manufacturing & supply chain efficiency
- Optimized for each of its two bands, no switching is required after amplification – unlike configurable architectures
The dual-band TRITIUM Duo implements proprietary TriQuint CuFlip™ technology to replace wire bonds with copper bumps. This reduces PCB real estate and enables superior system performance by eliminating noise-radiating wires. The copper bumps also dissipate heat better than traditional interconnect techniques. The integrated CuFlip BiHEMT power amplifier die achieves low current consumption to provide maximum talk-time and thermal efficiency critical for smartphone applications (see Figure 3).
The new TRITIUM Duo also employs a wafer level packaging (WLP) technique that eliminates bulky ceramic packages, significantly reducing size and increasing performance. The filter die is encapsulated within a polymer seal to create a protective air cavity around the filter area. This permits high-frequency operation and provides mechanical protection for the filter, enhancing performance. The approach also eliminates the ceramic cavity that would normally be needed around the duplexer, reducing overall size.
The dual-band modules feature two output power modes (high power mode/mid power mode), and low off and standby currents. This means longer talk times in portable applications, even without a DC/DC converter. The 2-in-1 PADs operate from a nominal battery voltage of 3 to 4.2 V. All control inputs are fully CMOS compatible and will interface easily with any modern baseband processor.
The TRITIUM Duo family is slated for production in September 2012.