Tiny LNAs improve GPS receive sensitivity over discrete or integrated receive solutions 


Tiny 1575MHz LNAs provide ultra-low 0.8dB GPS receive sensitivity and outperform discrete or highly integrated RF solutions. LNAs are ideal for GPS-enabled devices like cellular phones and personal navigational devices.

 
SUNNYVALE, CA--December 14, 2009--Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX2657 and MAX2658, which are two tiny, battery-sipping LNAs (low-noise amplifiers) designed for GPS-enabled applications operating in the 1575MHz band. Maxim merges its innovative SiGe BiCMOS process technology and WLP (wafer-level packaging) expertise in these devices, and they improve the performance of GPS receive sensitivity with an ultra-low 0.8dB noise figure. This sensitivity is an improvement over both discrete GaAs and Phempt LNAs or highly integrated RF CMOS solutions. Both devices consume less power than competitive solutions, and the high-linearity MAX2658 offers better in-band and out-of-band rejection than competitive devices. Ideal applications for these devices are cell phones, smartphones, PNDs (personal navigation devices), GPS-enabled fitness equipment like bicycle computers and watches, and GPS receiver modules.

Importance of better receiver performance and a tiny size

Signals for GPS systems originate from low earth-orbit satellites, and are often weak and hard to receive in urban environments or locations where other signals in nearby frequency bands interfere. In addition, today's low-cost single-chip GPS receivers use CMOS technology, which does not always provide the best receive sensitivity for front-end LNAs.

These RF CMOS receivers require an external LNA to boost the GPS signals as much as possible (without adding noise) in order to get a fix on the satellite signals and determine a location. This extra LNA increases both cost and size. Meanwhile, device manufacturers must minimize cost and size without sacrificing performance. It is thus no surprise that manufacturers are demanding a small ("How tiny can you make it?"), low-cost, high-performance LNA that will make a significant difference between a marginally performing GPS path or a high-performance GPS path.

Benefits of low power and high linearity

Customers can expect longer battery life in their GPS end equipment because the MAX2657 uses a low 4mA (typ) operating supply current. The MAX2658 consumes only 7.7mA for high-linearity performance that exceeds the competition. When not in use, the devices have a logic-enabled shutdown mode that reduces supply current to less than 1microamp.

Some customers will want to ensure the highest possible level of receive performance in the presence of in-band and out-of-band signal blockers. For these designs, the high-linearity MAX2658 will outperform other equipment in the area. Receiving the GPS signal in the presence of other blockers, the MAX2658 provides approximately 6dBm better in-band and out-of-band IIP3 for a mere 3.5mA extra supply current. 

Benefits of WLP Go Beyond Space Savings

The MAX2657 and MAX2658 use a space-saving 0.4mm pitch WLP package that requires a mere 1mm2 board space. The WLP is 20% smaller than the current competition. With only three off-the-shelf external components needed to complete the board-level design, these LNAs minimize the total board area required.

There is, finally, another critically important benefit of this tiny packaging. The MAX2657/MAX2658 are so small that either device can be placed extremely close to the antenna. This placement provides the best signal strength before amplifying it to the GPS receiver.

The MAX2657EWT+T and MAX2658EWT+T operate from a 1.6V to 3.3V supply. Specified over the -40 degrees Celsius to +85 degrees Celsius extended temperature range, they are available in an ultra-small 6 pin WLP. Prices start at $0.45 (1000-up, FOB USA). The MAX2657EVKIT and MAX2658EVKIT are also available for bench-level evaluation. Pricing for an EV kit is $50.00 (each, FOB USA). For more information please visit: www.maxim-ic.com/GPS-LNAs.

http://www.maxim-ic.com/MAX2657