wirelessZONE Products for the week of September 15, 2008
Avago Technologies Says…
ALM-1612: First High Gain GPS Low Noise Amplifier with Integrated FBAR Filter
Low Noise Figure/High Linearity Delivers Superior GPS Sensitivity in Ultra-Compact Size
Avago Technologies announced the availability of its next-generation high-gain GPS low noise amplifier (LNA) with integrated filter. The company is a leading supplier of analog interface components for communications, industrial and consumer applications. Under typical operating conditions of 2.7 V and 6 mA, Avago’s highly integrated ALM-1612 LNA/filter module delivers exceptional performance levels, including a 0.9 dB noise figure, 18 dB gain, +2 dBm input third order intercept point and more than 65 dBc of cell/PCS-band rejection. Designed for the 1.575 GHz frequency band, the ALM-1612 targets GPS handset, recreational, in-vehicle navigation and antenna markets.
Packaged in a 3.3 x 2.1 x 1.0 mm miniature MCOB package, the ALM-1612 is integrated with Avago’s industry leading FBAR filter for superior rejection at cell/PCS band frequencies, which is particularly critical for simultaneous GPS operation in handsets and other mobile applications. The ALM-1612 provides a CMOS-compatible shutdown pin to turn the LNA on/off or to adjust the variable current. A built-in shunt indicator at the RF input pin of the LNA enhances its ESD protection. Leveraging the company’s innovative 0.25 um enhancement-mode pHEMT fabrication technology, Avago’s ALM-1612 can also operate at low voltages of 1.8 V and still achieve very low noise figures and high gain, making it ideal for use in low-power GPS applications, such as handsets and portable GPS navigation devices.
EN-Genius Says…
We like FBAR technology here! When we reviewed the ACMD-7403 duplexer in January 2008 we referred back to the initial FBAR product we reviewed:
“We first wrote about FBAR when reviewing the first, then Agilent, filter using this MEMS technology. In May 2002, we said: “The ACPF-7001 has winner all over it and you should expect to see almost universal adoption in PCS-band handsets. No doubt there are other duplexers/filters in the offing and we should certainly expect to see a duplexer combined with a power module in the near future.” Certainly, from that point on, anybody who invested in SAW filter technology (how do you spell TriQuint?) would have had to have been blind. We never did get the combined RF amplifier and duplexer, which is a shame, but Agilent did get a Product of The Year Award from us.”
Well now we do have a combined amplifier/FBAR product, but it is on the receive side rather than the transmit side that we expected!
The ALM-1612 is a GPS band LNA with integrated FBAR bandpass filter for the 1.575 GHz GPS channels, an entirely logical application for the process. What surprised me was that in the architecture used, the filter followed the amplifier rather than the other way around – not a normal RF scenario. As it happens, though, the potential interferers are extremely unlikely to produce any products in the tight GPS band.
The amplifier is preceded by 50 Ω matching giving an S11 of about –9 dB.
The part is characterized fairly completely at both 1.8 V (the lowest operating voltage) and at 2.7 V. The parameters at the lower rail are a little poorer than the ones we quote here for 2.7 V.
Gain is a typical 18.2 dB with an incredible noise figure of 0.95 dB, a number that other purveyors of GaAs processes don’t seem to approach. And Avago doesn’t achieve the noise number at any real current cost, with a quiescent of 6 mA (shutdown is a typical 500 nA).
Input 1 dB compressed power is –8 dBm with IIP3 at +2 dBm (±2.5 MHz). The output return loss (S22) is a typical –14 dB, and reverse isolation (S21) is 27 dB.
The filter really does its work. Apart from UWB, which is an interfering modulation technology that the jury is still out on, the rejection of cells at 827.5 MHz is better than 69 dBc (cf output signal level) and 67 dB at 1.885 GHz for PCS.
Implementation of the ALM-1612 requires 3 external inductors, 2 resistors, and 3 decoupling capacitors requiring a very small amount of real estate.
This is going to be a huge volume product, a total no-brainer for the GPS front-ends of receivers in whatever format they are: portable standalones, in-vehicles, and within cell phones. The pricing is also extremely attractive.
The ALM-1612 is in production in MCOB-12 and is priced at $1.31 in 10-k piece lots.
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