Module manufacturers take note: NEC/CEL has a way for you to maintain a small footprint and use a GaAs MMIC surface-mount switch instead of dealing with die. The UPG2151T5K's 6-pin TSON package footprint measures a surprisingly small 1 x 1 mm, with a maximum height of 0.40 mm.
"NEC is trying to make the packages so small that OEMs can use them instead of chips," confirms Joe Grimm, Business Development Manager for California Eastern Laboratories, NEC's US arm.
NEC/CEL has been involved in the switch market for the past 5 or so years, and has seen its market share take off recently, and now estimates that it is one of the top five switch suppliers in the world. With an established line of switches, the company wanted to improve its competitive position by shrinking its designs even further.
So, how'd they do that? Grimm took a conservative approach to answer this question, "The process has to be improved so that everything can be much more confined on the device." Generally speaking, he credits advances in process technology, etching accuracy, and physics with the improvement.
While able to handle the 2.4-GHz frequency applications, such as Bluetooth and ZigBee, the switch is a great fit for products operating in the 902 to 928 MHz ISM band, including applications such as short range wireless, RFID, medical, security, and remote monitoring. It draws a 0.2 uA typical switch control current when powered by a +3-VDC supply.
"We are targeting people who are making modules or space-constrained products such as PCM/PCMIA cards that slide into computers or portable devices," says Grimm. These products continue to get thinner, so it is necessary to have very small components with very low profiles.
Although optimized for size, NEC ensured that the uPG2151T5K offers good performance for the most important switch specifications: low loss (0.30 dB typical at 0.5 to 1GHz), good isolation (25 dB typical at 0.5 to 1 GHz), and good switching speed (10 ns typical).
The company is committed to this small design, and plans to roll three or four more Pb-free switches in this same package over the coming months. For instance, the UPG2151T5K is a 1/2 W device, but a 1 W switch is in the works. Another version will have higher isolation for higher frequencies. Also in development is a single-control switch, which means that you will only need to send one signal to the switch, instead of two. "NEC is a leader in single-control switches, and we are seeing a lot of requests for this."
When module makers are sizing up their switch choices, the UPG2151T5K beats other surface-mount switches for size, and it is becoming competitive with chips, which measure about 0.5mm x 0.5 mm. One thing CEL wants you to keep in mind when considering chips is, "It's hard to RF test chips," explains Grimm, "and customers end up paying more money for a chip that is RF tested. If one chip turns out to be bad, you need to throw away an entire module. Our devices are 100% tested and guaranteed."
