Integrated circuits are gaining popularity as designers of hand-held consumer products find that their time to market can be reduced by eliminating the efforts needed to design stabilize discrete circuits. Although the discrete circuits claim high efficiency and low cost, they are difficult and time consuming to stabilize. GaAsTek's RF IC power amplifiers offer the alternative of high levels of functional integration with high degrees of ruggedness and stability, while other companies find that they do not have the time or resources to design discrete solutions. RF IC power amplifier products offer significant savings over hybrid modules and have been selected for many cost reduction redesigns.
These RF ICs are manufactured using a 0.6 mm, self-aligned, refractory gate, GaAs MESFET process named MSAG-Lite. Using simple, silicon MOSFET-like structure on GaAs, the MSAG family of processes permit the incorporation of enhancement/depletion mode FET logic, low noise transistors, and power transistors onto a single IC. By designing the MSAG-Lite process specifically for the RF IC market and low cost plastic packaging, GaASTek is able to compete cost effectively against silicon solutions for many RF front end applications. The MSAG-Lite technology is unique in its ability to provide 65% efficiency with a single, positive supply of 3V.
ITT's GaAsTek testing division is responsible for testing its own RF IC power amplifier products that serve a broad base of OEMs in the wireless personal market. These OEMs include manufacturers of cellular telephones, cordless telephones, cellular digital packet data devices, two-way pagers, narrowband PCS, and other wireless voice and data products.
GaAsTek's testing division employs the HP 84000 RFIC Testers to automate the testing process. The 84000 series is integrated with the Exatron's IC Handler which is designed specifically for testing power amplifier IC's. It also uses the high-performance workstation to keep processing time to a minimum. Operator can configure the system to meet the testing needs of power amplifiers going into cellular phones with any of the worldwide standard like CDMA, GSM, PHS and others.
The software interface allows the operator to enter device information and to select the appropriate test plans with the use of a mouse. Once the operator activates the process, the software provides continuous, run-time feedback to the him or her with a choice of simple pass/fail statistics or more detailed information for quick assessment of the test process status. This information allows the operator to stop a test run at the earliest possible moment if problems are detected, rather than waiting until the entire lot is finished. The followings are testing parameters for a typical GaAsTek's Amplifier for N-PCS applications.
| Characteristic | Typical |
Unit |
| Frequency Range | 900 to 942 |
MHz |
| Output Power | 1.2 |
W |
| Power Gain | 30.8 |
dB |
| Power Added Efficiency | 45 |
% |
| Second Harmonics Third Harmonics |
-36 -54 |
dBc dBc |
| Input VSWR | 1.4:1 |
- |
| Thermal Resistance | 33 |
Celsius/W |
| Rating | Value |
Unit |
| DC Supply Voltage | 5 |
Vdc |
| RF Input Power | 4 |
mW |
| Junction Temperature | 150 |
Celsius |
| Storage Temperature Range | -40 to 150 |
Celsius |
The handlers that GaAsTek utilizes are Exatron's 50800 series. Testing devices are loaded into the top of the handler. Typical loading methods are directly from tubes placed in the Input Tube Holder or from other unique methods. The devices are then indexed to a test contact mechanism. Among the standard choices, the customer may select special SMD (Surface Mount Device) test sites which plunge the Device Under Test (DUT) up to 1.5 inches past the back of the handler to a load board. Programming and testing takes place here, using any of several types of programmers and testers. After testing, failed devices are sorted into reject tubes. Devices which pass the test stage are sorted to the designated output for retrieval by the operator. Completed "Passed" devices can be returned to shipping tubes, passed onto tape & reel machines or bulk binned.
The handler's operation is constantly monitored by its STD Bus CPU. Once a device enters the handler, it is tracked by sensors as it passes through every step until it is positively placed in the correct output tube. If a device jam should occur, an appropriate error message will be displayed on the handler controller's front panel micro terminal. Most jams may be cleared by pressing the Run or Clear buttons on the front panel.
The handler may be operated in either of two modes: AUTO or MANUAL. MANUAL operation allows for Handler Diagnostics sequences to be run, Handler Set-Up changes to be entered, and mechanical adjustments to be made at the operator's convenience before, during, and after automatic Handler operation.
AUTO operation continuously cycles devices through the handler. The handler will stop when empty but re-start automatically when more devices are loaded. Each output tube may be filled to any pre-set amount, with individual counters keeping track of quantities in all outputs. When an output tube fills, the handler automatically begins to fill any other unfilled tube assigned to the sort signal received from the tester. When all output tubes are filled, the handler will stop and a message will be displayed, such as "ALL OUTPUTS FULL." The tube counter is automatically reset by removing the full tube and re-inserting an empty tube. The handler will not cycle devices to outputs which have no tubes or which are full. Additionally, a continuous subtotal count in maintained for each output, up to a total of 999,999 devices.
Sorting is accomplished by use of a stepper motor and a solenoid released shuttle. Dual positive binning sensors keep tack of the shuttle's position at all times. In the event of a sorting problem, a message will be displayed on the handler's front panel, and the devices will not be binned until the problem is corrected. The handler is guaranteed to properly bin every device even during "power down" conditions.
All Exatron Handlers are designed to permit direct docking with test heads to ensure that programmed test signal integrity is maintained. GaAsTek employs the Exatron's handlers which are designed to have a clean back surface to allow direct mounting of test heads on manipulators. The handlers equip with a tilting frame which allows setting to any angle from nearly vertical to nearly horizontal.
All handlers accommodate and use "plunge-to-board" test sites. That is, the handler places the DUT right onto the printed circuit board which carries the test site. This may be a large-scale tester ring board, or the direct tester electronics. Typically, the plunger can go as far as 1.5 inches past the back of the handler. Advantages can be gained from the use of plunge-to-board technology. First, lead lengths are reduced. This can be especially critical for RF test applications. Second, in conjunction with Particalization Process contractors, plunge-to-board allows placement of a DUT directly in the final application circuitry for a real in-circuit test.
Exatron Model 50800 used in GaAsTek
GaAsTek employs the Ismeca's automated Tape & Reel machine to handle its IC packaging process. With the increased use of high pin-count fine pitch devices, damaged leads have become one of the prime causes of failures in electronics IC manufacturing. So GaAsTek has to equip the machine with capability to inspect and recondition all types of integrated circuits. Every part of a IC is 100% vision inspected by the integrated vision system to ensure product quality in exceeding EIA standards.
The lead inspection system consists of a camera viewing from the top, a fibre optic light with two light guides and a simple I/O configuration. Picture is taken from each chip when it passes through the optical head. Defective IC chips are automatically sorted out to a separate bin.
Software interface of the vision system
All defective-proof components are then taped to the EIA Standard reels.
The Tape & Reel system must maintain the same quality standards to properly package
these devices by eliminating humidity, lead damage, and ensuring proper orientation.