Tony Testa continues his Wi-Fi Tech and Trends series with practical advice on overcoming thermal challenges in today’s smaller, sleeker, mesh network devices.

What kind of Wi-Fi thermal challenges are RF front-end designers experiencing?

We see two main design challenges.
 
First – there is an increase in demand for smaller, more sleeker routers, access points and wireless speakers that must be aesthetically and visually pleasing. Also, the consumer is migrating away from one wireless router per home toward a mesh network home, driving the need for a smaller and less obtrusive product. Additionally, Wi-Fi is designed into set-top-boxes, speakers, and voice assistant devices that are also becoming smaller and sleeker. Smaller and more pleasing to the eye is good for the consumer, but it creates additional pressure on the design as the devices inside have less area to properly dissipate the heat they create.

Second – in the enterprise space, the source of power for Wi-Fi products is in the Ethernet connection. This power source distributed over the Ethernet (POE) connection is limited. Thus, the challenge for product designers is to maximize the RF output power of the RF front-end with a limited POE power source. Therefore, efficient power dissipation (P_diss) is a must.

Power dissipation is defined as the amount of power consumed and converted to heat. Electronic devices produce heat, as an unwanted byproduct, which is a waste of energy. The desired state of any RF circuit is to reduce this wasteful heat and provide extensive RF output power, system efficiency and RF signal range.

This means RF front-end designers must create products that function using a low power source but produce high RF output power. And they also need to ensure their products remove heat efficiently to maximize RF output and reduce unwanted cooling fans or bulky heat-sinks. It is these heat-sinks or fans that hinder the manufacturer’s ability to meet the aesthetically pleasing product criteria.

 

Qorvo set out on an innovative design path to provide 2.4 and 5 GHz products that addressed both Wi-Fi 5 and Wi-Fi 6 solutions with multiple RF streams and voltage requirements. These products address the thermal and power dissipation challenge, but they also meet the small form factor requirement. The RF Front-End (RFFE) products Qorvo developed help enable a broad range of end-products and market sectors, such as retail, operator, enterprise and consumer. Qorvo was able to develop these RFFEs while shrinking the form factor acceptable to customer requirements.

 

What specific products does Qorvo suggest or use to address application thermal issues?

Heat can degrade overall system performance, impacting throughput, range and the ability to prevent interference. So, when designing Wi-Fi systems, it’s important to choose RFFE components that mitigate heat-related problems. Product designers should consider using a fully optimized, integrated front-end module (FEM) instead of discrete front-end components. This reduces line lengths and the need for additional tuning components, which contribute to insertion loss and system heat.

Part Number	Features
QPF4506	Integrates a 5GHz power amplifier (PA), regulator, single-pole-two-throw switch (SP2T) and low noise amplifier (LNA) with by-pass. Has superior efficient linearity effort vector magnitude (EVM), Pout and 2.4GHz rejection on the receive path. Optimized for 5-volt operation.
QPF4528	Integrates a 5GHz PA, regulator, SP2T switch, LNA with by-pass, coupler and voltage detector. Has superior efficient linearity EVM, Pout and 2.4GHz rejection on the receive path. Optimized for 3.3-volt operation.
QPF4588	Integrates a 5GHz PA, regulator, SP2T switch, LNA with by-pass and a coupler. Has superior efficient linearity EVM, Pout and 2.4GHz rejection on the receive path. Optimized for 5-volt operation.
QPF4800	Integrates a 2.4 and 5GHz power transmit and receive chains - PA, regulator, SP2T switch, bypassable LNA, and diplexer. Optimized for 5V supply voltage.
QPF7219	Integrates a 2.4GHz PA, SP2T switch, bypassable LNA, and bandedge BAW filter. Integrated die level filtering for 2nd and 3rd harmonics as well as 5GHz for DBDC operation are included. Optimized for 5-volt operation.

 

Qorvo’s RFFE products provide a complete solution, as well as meet the stringent thermal and RF range requirements. Because of Qorvo’s broad technology and integration capabilities, by integrating filter, PA, LNA, switch, detector and coupling in one package, we remove the expense and tedious design task of piecing these individual components together. This way, our customers can streamline their design process, reduce cost, certify products faster and meet stringent time-to-market schedules by leveraging our all-in-one RFFE solutions. Our latest products that customers are most excited about are the QPF4588, QPF4528 and QPF4506.

 

Tony's Final Thoughts:

We described several heat-related sources in today’s Wi-Fi products, such as the increase in RF pathways and smaller, sleeker end-product designs. We also noted the RFFE parameters associated with thermal heat, such as power dissipation and efficiency. Qorvo has worked closely with customers to understand Wi-Fi product thermal causes and mitigation. To effectively beat the heat, use Qorvo fully functioning RFFE products. They have been designed to address the latest market trends and design initiatives that increase the end-product heat. Besides the additional advantages that come with using fully functioning RFFEs, you will achieve savings in both design time and time-to-market.