StratEdge was contracted by TriQuint Semiconductor, a manufacturer of GaAs MMIC components, for package, assembly and test services for one of their newest devices. The resulting product, a wideband, medium power amplifier (MPA) with automatic gain control (AGC), is currently being offered by TriQuint as a custom part. The packaged part is especially well suited as an AGC amplifier or laser modulator driver amplifier in OC-192 fiber optic systems. The product is an excellent fit to meet 10 Gbps optical requirements by providing 11 dB of gain, ±0.2dB ripple, across the 50 kHz to 8 GHz frequency range.
StratEdge already had standard packages that would meet the high frequency requirements of the TriQuint chips. In particular, the 580286 power amplifier package is optimized for Ku-band electrical performance and specified for DC through 23 GHz applications. However, StratEdge was asked to perform the entire assembly process including trim, labeling, build and test, and provide finished devices for delivery to the end-user. Completed parts were binned (grouped) based on very tight electrical performance specifications. The parts were labeled with the customer name, serial number of the part and bin number, and placed in antistatic bags for shipment. The finished product was then shipped to the end-user as a custom device.
StratEdge was given performance requirements and specifications for the components, and could use the packages they had, but had to supply custom 50 ‡ lines to take up the gap difference in the package so there would be a continuous circuit with no holes or gaps. (In the next phase of the process a custom cavity will be designed and manufactured to specifically fit these components so extra time is not required to fill the gaps and the assembly process can be shortened.) For this application, precise placement of all components inside the package is critical to performance.
The base material for the package is a copper composite with a laminated ceramic substrate of 96 percent Al2 O3 alumina. The packages are first soldered together and then nickel and gold plated. Gold plating on the leads, base and ceramic is 50 microinches minimum with a 100 to 350 microinch nickel underplate.
Assembly of DC through 23 GHz packages requires a class 100 work area and a combination of a eutectic die attach application and conductive epoxy, with the interconnects finally attached with an automated gold wire bonder. After the die is attached, the packages are covered and tested with a HP 8510C network analyzer. The finished product is a ten-lead package with two RF I/Os. Figure 1 shows the MPA package outline. Figure 2 shows the sealed device being placed in a test fixture for performance evaluation.
The final 0.682" x 0.450" amplifier features a 30 kHz to 14 GHz frequency range with 11 dB of small-signal gain and a gain flatness of ±0.2 dB. The amplifier is capable of 6 V peak-to-peak output and a 3 dB noise figure. Nominal bias is 8 V at 88 mA. Figure 3 shows the MPA's wideband gain performance in the completed package.
The product has been offered by TriQuint as a custom device. StratEdge has since been contracted by other customers requiring the design, manufacture, assembly and test of similar packages for a variety of applications. These other applications include devices in this frequency band, a wideband gain block, a post amplifier for receiving systems and others requiring a wideband flat response with medium output power levels.
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Circle No. 302